Removed extra 'an' in ext4 docs. #9

smartinez87 · 2011-09-05T21:37:49Z

There as an extra 'an' in this doc, so I removed it.

jacobh · 2011-09-06T04:04:26Z

thankyou kind sir, your commit will not go unnoticed.

bdonlan · 2011-09-06T13:59:03Z

Please note that pull requests are not the proper procedure to submit patches to the Linux kernel (Linus put the kernel up here because kernel.org's master mirror is down; it seems that he doesn't like the pull request system[1], but github does not allow him to disable it). Please read Documentation/SubmittingPatches - you must write a proper commit message, add a Signed-Off-By line, and submit to the linux kernel mailing list, CCing the affected maintainers (ie, not Linus in most cases).

[1] - http://blueparen.com/node/12

smartinez87 · 2011-09-06T14:21:24Z

can you please point me at some url where I can read that submitting patches documentation? thanks!

snarkyMcSnark · 2011-09-06T14:58:38Z

smartinez87, this is pretty silly stuffs, these stunt-style pull requests that have been coming into this repo lately. Sure it's open source and you want to help fix it, but as bdonlan notes above, there are proper guidelines to be followed to submit patches to be fixed. A simpler solution (lifted wholesale from reddit here btw): someone volunteers to run the "typo in the readme" branch. People send pull requests to them. When that branch has a delta of more than a couple fucking kilobytes, then a reasonable pull request can be sent to the main project.

Also look at this link to the Kernel Janitors site please in the future for things related to code quality guidelines cleaner-uppers in the kernel.

Let's not distract and annoy Linus with such silly trivialities like this, it just makes you look like a jackass.

dovydasm · 2011-09-06T15:02:22Z

Bravo!

smartinez87 · 2011-09-06T15:21:38Z

hey, I just don't care about this, just noticed the typo and wanted the people that can do something about this to know about it and fix it. If no one care about the docs, I care even less.

VM2 · 2011-09-07T04:59:53Z

@snarkyMcSnark is right. @smartinez87 is just unnecessarily trying to create work for a high profile project just to be part of the commit history. His background points to the same. He claims to be a core contributor for the rails project although his entire commit history consists solely of frivolous grammatical and whitespace changes to the documentation. In fact he has no original commits for documentation either just small formatting changes to existing commits. This is entirely true.

@diegoviola, instead of you two trying to fix whitespace issues and unnecessarily trying to police other contributors you should work on something useful. These are all valid arguments and the original committer has a bad history of doing this and 3 people have already pointed that out.

commit fe47ae7 upstream. The lockdep warning below detects a possible A->B/B->A locking dependency of mm->mmap_sem and dcookie_mutex. The order in sync_buffer() is mm->mmap_sem/dcookie_mutex, while in sys_lookup_dcookie() it is vice versa. Fixing it in sys_lookup_dcookie() by unlocking dcookie_mutex before copy_to_user(). oprofiled/4432 is trying to acquire lock: (&mm->mmap_sem){++++++}, at: [<ffffffff810b444b>] might_fault+0x53/0xa3 but task is already holding lock: (dcookie_mutex){+.+.+.}, at: [<ffffffff81124d28>] sys_lookup_dcookie+0x45/0x149 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (dcookie_mutex){+.+.+.}: [<ffffffff8106557f>] lock_acquire+0xf8/0x11e [<ffffffff814634f0>] mutex_lock_nested+0x63/0x309 [<ffffffff81124e5c>] get_dcookie+0x30/0x144 [<ffffffffa0000fba>] sync_buffer+0x196/0x3ec [oprofile] [<ffffffffa0001226>] task_exit_notify+0x16/0x1a [oprofile] [<ffffffff81467b96>] notifier_call_chain+0x37/0x63 [<ffffffff8105803d>] __blocking_notifier_call_chain+0x50/0x67 [<ffffffff81058068>] blocking_notifier_call_chain+0x14/0x16 [<ffffffff8105a718>] profile_task_exit+0x1a/0x1c [<ffffffff81039e8f>] do_exit+0x2a/0x6fc [<ffffffff8103a5e4>] do_group_exit+0x83/0xae [<ffffffff8103a626>] sys_exit_group+0x17/0x1b [<ffffffff8146ad4b>] system_call_fastpath+0x16/0x1b -> #0 (&mm->mmap_sem){++++++}: [<ffffffff81064dfb>] __lock_acquire+0x1085/0x1711 [<ffffffff8106557f>] lock_acquire+0xf8/0x11e [<ffffffff810b4478>] might_fault+0x80/0xa3 [<ffffffff81124de7>] sys_lookup_dcookie+0x104/0x149 [<ffffffff8146ad4b>] system_call_fastpath+0x16/0x1b other info that might help us debug this: 1 lock held by oprofiled/4432: #0: (dcookie_mutex){+.+.+.}, at: [<ffffffff81124d28>] sys_lookup_dcookie+0x45/0x149 stack backtrace: Pid: 4432, comm: oprofiled Not tainted 2.6.39-00008-ge5a450d #9 Call Trace: [<ffffffff81063193>] print_circular_bug+0xae/0xbc [<ffffffff81064dfb>] __lock_acquire+0x1085/0x1711 [<ffffffff8102ef13>] ? get_parent_ip+0x11/0x42 [<ffffffff810b444b>] ? might_fault+0x53/0xa3 [<ffffffff8106557f>] lock_acquire+0xf8/0x11e [<ffffffff810b444b>] ? might_fault+0x53/0xa3 [<ffffffff810d7d54>] ? path_put+0x22/0x27 [<ffffffff810b4478>] might_fault+0x80/0xa3 [<ffffffff810b444b>] ? might_fault+0x53/0xa3 [<ffffffff81124de7>] sys_lookup_dcookie+0x104/0x149 [<ffffffff8146ad4b>] system_call_fastpath+0x16/0x1b References: https://bugzilla.kernel.org/show_bug.cgi?id=13809 Signed-off-by: Robert Richter <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

In commit 5ec094c "nfsd4: extend state lock over seqid replay logic" I modified the exit logic of all the seqid-based procedures except nfsd4_locku(). Fix the oversight. The result of the bug was a double-unlock while handling the LOCKU procedure, and a warning like: [ 142.150014] WARNING: at kernel/mutex-debug.c:78 debug_mutex_unlock+0xda/0xe0() ... [ 142.152927] Pid: 742, comm: nfsd Not tainted 3.1.0-rc1-SLIM+ torvalds#9 [ 142.152927] Call Trace: [ 142.152927] [<ffffffff8105fa4f>] warn_slowpath_common+0x7f/0xc0 [ 142.152927] [<ffffffff8105faaa>] warn_slowpath_null+0x1a/0x20 [ 142.152927] [<ffffffff810960ca>] debug_mutex_unlock+0xda/0xe0 [ 142.152927] [<ffffffff813e4200>] __mutex_unlock_slowpath+0x80/0x140 [ 142.152927] [<ffffffff813e42ce>] mutex_unlock+0xe/0x10 [ 142.152927] [<ffffffffa03bd3f5>] nfs4_lock_state+0x35/0x40 [nfsd] [ 142.152927] [<ffffffffa03b0b71>] nfsd4_proc_compound+0x2a1/0x690 [nfsd] [ 142.152927] [<ffffffffa039f9fb>] nfsd_dispatch+0xeb/0x230 [nfsd] [ 142.152927] [<ffffffffa02b1055>] svc_process_common+0x345/0x690 [sunrpc] [ 142.152927] [<ffffffff81058d10>] ? try_to_wake_up+0x280/0x280 [ 142.152927] [<ffffffffa02b16e2>] svc_process+0x102/0x150 [sunrpc] [ 142.152927] [<ffffffffa039f0bd>] nfsd+0xbd/0x160 [nfsd] [ 142.152927] [<ffffffffa039f000>] ? 0xffffffffa039efff [ 142.152927] [<ffffffff8108230c>] kthread+0x8c/0xa0 [ 142.152927] [<ffffffff813e8694>] kernel_thread_helper+0x4/0x10 [ 142.152927] [<ffffffff81082280>] ? kthread_worker_fn+0x190/0x190 [ 142.152927] [<ffffffff813e8690>] ? gs_change+0x13/0x13 Reported-by: Bryan Schumaker <[email protected]> Tested-by: Bryan Schumaker <[email protected]> Signed-off-by: J. Bruce Fields <[email protected]>

If the pte mapping in generic_perform_write() is unmapped between iov_iter_fault_in_readable() and iov_iter_copy_from_user_atomic(), the "copied" parameter to ->end_write can be zero. ext4 couldn't cope with it with delayed allocations enabled. This skips the i_disksize enlargement logic if copied is zero and no new data was appeneded to the inode. gdb> bt #0 0xffffffff811afe80 in ext4_da_should_update_i_disksize (file=0xffff88003f606a80, mapping=0xffff88001d3824e0, pos=0x1\ 08000, len=0x1000, copied=0x0, page=0xffffea0000d792e8, fsdata=0x0) at fs/ext4/inode.c:2467 #1 ext4_da_write_end (file=0xffff88003f606a80, mapping=0xffff88001d3824e0, pos=0x108000, len=0x1000, copied=0x0, page=0\ xffffea0000d792e8, fsdata=0x0) at fs/ext4/inode.c:2512 #2 0xffffffff810d97f1 in generic_perform_write (iocb=<value optimized out>, iov=<value optimized out>, nr_segs=<value o\ ptimized out>, pos=0x108000, ppos=0xffff88001e26be40, count=<value optimized out>, written=0x0) at mm/filemap.c:2440 #3 generic_file_buffered_write (iocb=<value optimized out>, iov=<value optimized out>, nr_segs=<value optimized out>, p\ os=0x108000, ppos=0xffff88001e26be40, count=<value optimized out>, written=0x0) at mm/filemap.c:2482 #4 0xffffffff810db5d1 in __generic_file_aio_write (iocb=0xffff88001e26bde8, iov=0xffff88001e26bec8, nr_segs=0x1, ppos=0\ xffff88001e26be40) at mm/filemap.c:2600 #5 0xffffffff810db853 in generic_file_aio_write (iocb=0xffff88001e26bde8, iov=0xffff88001e26bec8, nr_segs=<value optimi\ zed out>, pos=<value optimized out>) at mm/filemap.c:2632 #6 0xffffffff811a71aa in ext4_file_write (iocb=0xffff88001e26bde8, iov=0xffff88001e26bec8, nr_segs=0x1, pos=0x108000) a\ t fs/ext4/file.c:136 #7 0xffffffff811375aa in do_sync_write (filp=0xffff88003f606a80, buf=<value optimized out>, len=<value optimized out>, \ ppos=0xffff88001e26bf48) at fs/read_write.c:406 #8 0xffffffff81137e56 in vfs_write (file=0xffff88003f606a80, buf=0x1ec2960 <Address 0x1ec2960 out of bounds>, count=0x4\ 000, pos=0xffff88001e26bf48) at fs/read_write.c:435 #9 0xffffffff8113816c in sys_write (fd=<value optimized out>, buf=0x1ec2960 <Address 0x1ec2960 out of bounds>, count=0x\ 4000) at fs/read_write.c:487 #10 <signal handler called> #11 0x00007f120077a390 in __brk_reservation_fn_dmi_alloc__ () #12 0x0000000000000000 in ?? () gdb> print offset $22 = 0xffffffffffffffff gdb> print idx $23 = 0xffffffff gdb> print inode->i_blkbits $24 = 0xc gdb> up #1 ext4_da_write_end (file=0xffff88003f606a80, mapping=0xffff88001d3824e0, pos=0x108000, len=0x1000, copied=0x0, page=0\ xffffea0000d792e8, fsdata=0x0) at fs/ext4/inode.c:2512 2512 if (ext4_da_should_update_i_disksize(page, end)) { gdb> print start $25 = 0x0 gdb> print end $26 = 0xffffffffffffffff gdb> print pos $27 = 0x108000 gdb> print new_i_size $28 = 0x108000 gdb> print ((struct ext4_inode_info *)((char *)inode-((int)(&((struct ext4_inode_info *)0)->vfs_inode))))->i_disksize $29 = 0xd9000 gdb> down 2467 for (i = 0; i < idx; i++) gdb> print i $30 = 0xd44acbee This is 100% reproducible with some autonuma development code tuned in a very aggressive manner (not normal way even for knumad) which does "exotic" changes to the ptes. It wouldn't normally trigger but I don't see why it can't happen normally if the page is added to swap cache in between the two faults leading to "copied" being zero (which then hangs in ext4). So it should be fixed. Especially possible with lumpy reclaim (albeit disabled if compaction is enabled) as that would ignore the young bits in the ptes. Signed-off-by: Andrea Arcangeli <[email protected]> Signed-off-by: "Theodore Ts'o" <[email protected]> Cc: [email protected]

qeth layer3 recovery invokes its set_multicast_list function, which invokes function __vlan_find_dev_deep requiring rcu_read_lock or rtnl lock. This causes kernel messages: kernel: [ INFO: suspicious rcu_dereference_check() usage. ] kernel: --------------------------------------------------- kernel: net/8021q/vlan_core.c:70 invoked rcu_dereference_check() without protection! kernel: stack backtrace: kernel: CPU: 0 Not tainted 3.1.0 torvalds#9 kernel: Process qeth_recover (pid: 2078, task: 000000007e584680, ksp: 000000007e3e3930) kernel: 000000007e3e3d08 000000007e3e3c88 0000000000000002 0000000000000000 kernel: 000000007e3e3d28 000000007e3e3ca0 000000007e3e3ca0 00000000005e77ce kernel: 0000000000000000 0000000000000001 ffffffffffffffff 0000000000000001 kernel: 000000000000000d 000000000000000c 000000007e3e3cf0 0000000000000000 kernel: 0000000000000000 0000000000100a18 000000007e3e3c88 000000007e3e3cc8 kernel: Call Trace: kernel: ([<0000000000100926>] show_trace+0xee/0x144) kernel: [<00000000005d395c>] __vlan_find_dev_deep+0xb0/0x108 kernel: [<00000000004acd3a>] qeth_l3_set_multicast_list+0x976/0xe38 kernel: [<00000000004ae0f4>] __qeth_l3_set_online+0x75c/0x1498 kernel: [<00000000004aefec>] qeth_l3_recover+0xc4/0x1d0 kernel: [<0000000000185372>] kthread+0xa6/0xb0 kernel: [<00000000005ed4c6>] kernel_thread_starter+0x6/0xc kernel: [<00000000005ed4c0>] kernel_thread_starter+0x0/0xc The patch makes sure the rtnl lock is held once qeth recovery invokes its set_multicast_list function. Signed-off-by: Ursula Braun <[email protected]> Signed-off-by: Frank Blaschka <[email protected]> Signed-off-by: David S. Miller <[email protected]>

commit fe47ae7 upstream. The lockdep warning below detects a possible A->B/B->A locking dependency of mm->mmap_sem and dcookie_mutex. The order in sync_buffer() is mm->mmap_sem/dcookie_mutex, while in sys_lookup_dcookie() it is vice versa. Fixing it in sys_lookup_dcookie() by unlocking dcookie_mutex before copy_to_user(). oprofiled/4432 is trying to acquire lock: (&mm->mmap_sem){++++++}, at: [<ffffffff810b444b>] might_fault+0x53/0xa3 but task is already holding lock: (dcookie_mutex){+.+.+.}, at: [<ffffffff81124d28>] sys_lookup_dcookie+0x45/0x149 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (dcookie_mutex){+.+.+.}: [<ffffffff8106557f>] lock_acquire+0xf8/0x11e [<ffffffff814634f0>] mutex_lock_nested+0x63/0x309 [<ffffffff81124e5c>] get_dcookie+0x30/0x144 [<ffffffffa0000fba>] sync_buffer+0x196/0x3ec [oprofile] [<ffffffffa0001226>] task_exit_notify+0x16/0x1a [oprofile] [<ffffffff81467b96>] notifier_call_chain+0x37/0x63 [<ffffffff8105803d>] __blocking_notifier_call_chain+0x50/0x67 [<ffffffff81058068>] blocking_notifier_call_chain+0x14/0x16 [<ffffffff8105a718>] profile_task_exit+0x1a/0x1c [<ffffffff81039e8f>] do_exit+0x2a/0x6fc [<ffffffff8103a5e4>] do_group_exit+0x83/0xae [<ffffffff8103a626>] sys_exit_group+0x17/0x1b [<ffffffff8146ad4b>] system_call_fastpath+0x16/0x1b -> #0 (&mm->mmap_sem){++++++}: [<ffffffff81064dfb>] __lock_acquire+0x1085/0x1711 [<ffffffff8106557f>] lock_acquire+0xf8/0x11e [<ffffffff810b4478>] might_fault+0x80/0xa3 [<ffffffff81124de7>] sys_lookup_dcookie+0x104/0x149 [<ffffffff8146ad4b>] system_call_fastpath+0x16/0x1b other info that might help us debug this: 1 lock held by oprofiled/4432: #0: (dcookie_mutex){+.+.+.}, at: [<ffffffff81124d28>] sys_lookup_dcookie+0x45/0x149 stack backtrace: Pid: 4432, comm: oprofiled Not tainted 2.6.39-00008-ge5a450d torvalds#9 Call Trace: [<ffffffff81063193>] print_circular_bug+0xae/0xbc [<ffffffff81064dfb>] __lock_acquire+0x1085/0x1711 [<ffffffff8102ef13>] ? get_parent_ip+0x11/0x42 [<ffffffff810b444b>] ? might_fault+0x53/0xa3 [<ffffffff8106557f>] lock_acquire+0xf8/0x11e [<ffffffff810b444b>] ? might_fault+0x53/0xa3 [<ffffffff810d7d54>] ? path_put+0x22/0x27 [<ffffffff810b4478>] might_fault+0x80/0xa3 [<ffffffff810b444b>] ? might_fault+0x53/0xa3 [<ffffffff81124de7>] sys_lookup_dcookie+0x104/0x149 [<ffffffff8146ad4b>] system_call_fastpath+0x16/0x1b References: https://bugzilla.kernel.org/show_bug.cgi?id=13809 Signed-off-by: Robert Richter <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> Signed-off-by: Andi Kleen <[email protected]>

$ wget "http://pkgs.fedoraproject.org/gitweb/?p=kernel.git;a=blob_plain;f=mac80211_offchannel_rework_revert.patch;h=859799714cd85a58450ecde4a1dabc5adffd5100;hb=refs/heads/f16" -O mac80211_offchannel_rework_revert.patch $ patch -p1 --dry-run < mac80211_offchannel_rework_revert.patch patching file net/mac80211/ieee80211_i.h Hunk #1 succeeded at 702 (offset 8 lines). Hunk #2 succeeded at 712 (offset 8 lines). Hunk #3 succeeded at 1143 (offset -57 lines). patching file net/mac80211/main.c patching file net/mac80211/offchannel.c Hunk #1 succeeded at 18 (offset 1 line). Hunk #2 succeeded at 42 (offset 1 line). Hunk #3 succeeded at 78 (offset 1 line). Hunk #4 succeeded at 96 (offset 1 line). Hunk #5 succeeded at 162 (offset 1 line). Hunk torvalds#6 succeeded at 182 (offset 1 line). patching file net/mac80211/rx.c Hunk #1 succeeded at 421 (offset 4 lines). Hunk #2 succeeded at 2864 (offset 87 lines). patching file net/mac80211/scan.c Hunk #1 succeeded at 213 (offset 1 line). Hunk #2 succeeded at 256 (offset 2 lines). Hunk #3 succeeded at 288 (offset 2 lines). Hunk #4 succeeded at 333 (offset 2 lines). Hunk #5 succeeded at 482 (offset 2 lines). Hunk torvalds#6 succeeded at 498 (offset 2 lines). Hunk torvalds#7 succeeded at 516 (offset 2 lines). Hunk torvalds#8 succeeded at 530 (offset 2 lines). Hunk torvalds#9 succeeded at 555 (offset 2 lines). patching file net/mac80211/tx.c Hunk #1 succeeded at 259 (offset 1 line). patching file net/mac80211/work.c Hunk #1 succeeded at 899 (offset -2 lines). Hunk #2 succeeded at 949 (offset -2 lines). Hunk #3 succeeded at 1046 (offset -2 lines). Hunk #4 succeeded at 1054 (offset -2 lines).

If the netdev is already in NETREG_UNREGISTERING/_UNREGISTERED state, do not update the real num tx queues. netdev_queue_update_kobjects() is already called via remove_queue_kobjects() at NETREG_UNREGISTERING time. So, when upper layer driver, e.g., FCoE protocol stack is monitoring the netdev event of NETDEV_UNREGISTER and calls back to LLD ndo_fcoe_disable() to remove extra queues allocated for FCoE, the associated txq sysfs kobjects are already removed, and trying to update the real num queues would cause something like below: ... PID: 25138 TASK: ffff88021e64c440 CPU: 3 COMMAND: "kworker/3:3" #0 [ffff88021f007760] machine_kexec at ffffffff810226d9 #1 [ffff88021f0077d0] crash_kexec at ffffffff81089d2d #2 [ffff88021f0078a0] oops_end at ffffffff813bca78 #3 [ffff88021f0078d0] no_context at ffffffff81029e72 #4 [ffff88021f007920] __bad_area_nosemaphore at ffffffff8102a155 #5 [ffff88021f0079f0] bad_area_nosemaphore at ffffffff8102a23e torvalds#6 [ffff88021f007a00] do_page_fault at ffffffff813bf32e torvalds#7 [ffff88021f007b10] page_fault at ffffffff813bc045 [exception RIP: sysfs_find_dirent+17] RIP: ffffffff81178611 RSP: ffff88021f007bc0 RFLAGS: 00010246 RAX: ffff88021e64c440 RBX: ffffffff8156cc63 RCX: 0000000000000004 RDX: ffffffff8156cc63 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88021f007be0 R8: 0000000000000004 R9: 0000000000000008 R10: ffffffff816fed00 R11: 0000000000000004 R12: 0000000000000000 R13: ffffffff8156cc63 R14: 0000000000000000 R15: ffff8802222a0000 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 torvalds#8 [ffff88021f007be8] sysfs_get_dirent at ffffffff81178c07 torvalds#9 [ffff88021f007c18] sysfs_remove_group at ffffffff8117ac27 torvalds#10 [ffff88021f007c48] netdev_queue_update_kobjects at ffffffff813178f9 torvalds#11 [ffff88021f007c88] netif_set_real_num_tx_queues at ffffffff81303e38 torvalds#12 [ffff88021f007cc8] ixgbe_set_num_queues at ffffffffa0249763 [ixgbe] torvalds#13 [ffff88021f007cf8] ixgbe_init_interrupt_scheme at ffffffffa024ea89 [ixgbe] torvalds#14 [ffff88021f007d48] ixgbe_fcoe_disable at ffffffffa0267113 [ixgbe] torvalds#15 [ffff88021f007d68] vlan_dev_fcoe_disable at ffffffffa014fef5 [8021q] torvalds#16 [ffff88021f007d78] fcoe_interface_cleanup at ffffffffa02b7dfd [fcoe] torvalds#17 [ffff88021f007df8] fcoe_destroy_work at ffffffffa02b7f08 [fcoe] torvalds#18 [ffff88021f007e18] process_one_work at ffffffff8105d7ca torvalds#19 [ffff88021f007e68] worker_thread at ffffffff81060513 torvalds#20 [ffff88021f007ee8] kthread at ffffffff810648b6 torvalds#21 [ffff88021f007f48] kernel_thread_helper at ffffffff813c40f4 Signed-off-by: Yi Zou <[email protected]> Tested-by: Ross Brattain <[email protected]> Tested-by: Stephen Ko <[email protected]> Signed-off-by: Jeff Kirsher <[email protected]>

…S block during isolation for migration commit 0bf380b upstream. When isolating for migration, migration starts at the start of a zone which is not necessarily pageblock aligned. Further, it stops isolating when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally not aligned. This allows isolate_migratepages() to call pfn_to_page() on an invalid PFN which can result in a crash. This was originally reported against a 3.0-based kernel with the following trace in a crash dump. PID: 9902 TASK: d47aecd0 CPU: 0 COMMAND: "memcg_process_s" #0 [d72d3ad0] crash_kexec at c028cfdb #1 [d72d3b24] oops_end at c05c5322 #2 [d72d3b38] __bad_area_nosemaphore at c0227e60 #3 [d72d3bec] bad_area at c0227fb6 #4 [d72d3c00] do_page_fault at c05c72ec #5 [d72d3c80] error_code (via page_fault) at c05c47a4 EAX: 00000000 EBX: 000c0000 ECX: 00000001 EDX: 00000807 EBP: 000c0000 DS: 007b ESI: 00000001 ES: 007b EDI: f3000a80 GS: 6f50 CS: 0060 EIP: c030b15a ERR: ffffffff EFLAGS: 00010002 torvalds#6 [d72d3cb4] isolate_migratepages at c030b15a torvalds#7 [d72d3d1] zone_watermark_ok at c02d26cb torvalds#8 [d72d3d2c] compact_zone at c030b8de torvalds#9 [d72d3d68] compact_zone_order at c030bba1 torvalds#10 [d72d3db4] try_to_compact_pages at c030bc84 torvalds#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7 torvalds#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7 torvalds#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97 torvalds#14 [d72d3eb8] alloc_pages_vma at c030a845 torvalds#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb torvalds#16 [d72d3f00] handle_mm_fault at c02f36c6 torvalds#17 [d72d3f30] do_page_fault at c05c70ed torvalds#18 [d72d3fb0] error_code (via page_fault) at c05c47a4 EAX: b71ff000 EBX: 00000001 ECX: 00001600 EDX: 00000431 DS: 007b ESI: 08048950 ES: 007b EDI: bfaa3788 SS: 007b ESP: bfaa36e0 EBP: bfaa3828 GS: 6f50 CS: 0073 EIP: 080487c8 ERR: ffffffff EFLAGS: 00010202 It was also reported by Herbert van den Bergh against 3.1-based kernel with the following snippet from the console log. BUG: unable to handle kernel paging request at 01c00008 IP: [<c0522399>] isolate_migratepages+0x119/0x390 *pdpt = 000000002f7ce001 *pde = 0000000000000000 It is expected that it also affects 3.2.x and current mainline. The problem is that pfn_valid is only called on the first PFN being checked and that PFN is not necessarily aligned. Lets say we have a case like this H = MAX_ORDER_NR_PAGES boundary | = pageblock boundary m = cc->migrate_pfn f = cc->free_pfn o = memory hole H------|------H------|----m-Hoooooo|ooooooH-f----|------H The migrate_pfn is just below a memory hole and the free scanner is beyond the hole. When isolate_migratepages started, it scans from migrate_pfn to migrate_pfn+pageblock_nr_pages which is now in a memory hole. It checks pfn_valid() on the first PFN but then scans into the hole where there are not necessarily valid struct pages. This patch ensures that isolate_migratepages calls pfn_valid when necessary. Reported-by: Herbert van den Bergh <[email protected]> Tested-by: Herbert van den Bergh <[email protected]> Signed-off-by: Mel Gorman <[email protected]> Acked-by: Michal Nazarewicz <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

…s are not initialised Current ARM local timer code registers CPUFREQ notifiers even in case the twd_timer_setup() isn't called. That seems to be wrong and would eventually lead to kernel crash on the CPU frequency transitions on the SOCs where the local timer doesn't exist or broken because of hardware BUG. Fix it by testing twd_evt and *__this_cpu_ptr(twd_evt). The issue was observed with v3.3-rc3 and building an OMAP2+ kernel on OMAP3 SOC which doesn't have TWD. Below is the dump for reference : Unable to handle kernel paging request at virtual address 007e900 pgd = cdc20000 [007e9000] *pgd=00000000 Internal error: Oops: 5 [#1] SMP Modules linked in: CPU: 0 Not tainted (3.3.0-rc3-pm+debug+initramfs #9) PC is at twd_update_frequency+0x34/0x48 LR is at twd_update_frequency+0x10/0x48 pc : [<c001382c>] lr : [<c0013808>] psr: 60000093 sp : ce311dd8 ip : 00000000 fp : 00000000 r10: 00000000 r9 : 00000001 r8 : ce310000 r7 : c0440458 r6 : c00137f8 r5 : 00000000 r4 : c0947a74 r3 : 00000000 r2 : 007e9000 r1 : 00000000 r0 : 00000000 Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment usr Control: 10c5387d Table: 8dc20019 DAC: 00000015 Process sh (pid: 599, stack limit = 0xce3102f8) Stack: (0xce311dd8 to 0xce312000) 1dc0: 6000c 1de0: 00000001 00000002 00000000 00000000 00000000 00000000 00000 1e00: ffffffff c093d8f0 00000000 ce311ebc 00000001 00000001 ce310 1e20: c001386c c0437c4c c0e95b60 c0e95ba8 00000001 c0e95bf8 ffff4 1e40: 00000000 00000000 c005ef74 ce310000 c0435cf0 ce311ebc 00000 1e60: ce352b40 0007a120 c08d5108 c08ba040 c08ba040 c005f030 00000 1e80: c08bc554 c032fe2c 0007a120 c08d4b64 ce352b40 c08d8618 ffff8 1ea0: c08ba040 c033364c ce311ecc c0433b50 00000002 ffffffea c0330 1ec0: 0007a120 0007a120 22222201 00000000 22222222 00000000 ce357 1ee0: ce3d6000 cdc2aed8 ce352ba0 c0470164 00000002 c032f47c 00034 1f00: c0331cac ce352b40 00000007 c032f6d0 ce352bbc 0003d090 c0930 1f20: c093d8bc c03306a4 00000007 ce311f80 00000007 cdc2aec0 ce358 1f40: ce8d20c0 00000007 b6fe5000 ce311f80 00000007 ce310000 0000c 1f60: c000de74 ce987400 ce8d20c0 b6fe5000 00000000 00000000 0000c 1f80: 00000000 00000000 001fbac8 00000000 00000007 001fbac8 00004 1fa0: c000df04 c000dd60 00000007 001fbac8 00000001 b6fe5000 00000 1fc0: 00000007 001fbac8 00000007 00000004 b6fe5000 00000000 00202 1fe0: 00000000 beb565f8 00101ffc 00008e8c 60000010 00000001 00000 [<c001382c>] (twd_update_frequency+0x34/0x48) from [<c008ac4c>] ) [<c008ac4c>] (smp_call_function_single+0x17c/0x1c8) from [<c0013) [<c0013890>] (twd_cpufreq_transition+0x24/0x30) from [<c0437c4c>) [<c0437c4c>] (notifier_call_chain+0x44/0x84) from [<c005efe4>] () [<c005efe4>] (__srcu_notifier_call_chain+0x70/0xa4) from [<c005f) [<c005f030>] (srcu_notifier_call_chain+0x18/0x20) from [<c032fe2) [<c032fe2c>] (cpufreq_notify_transition+0xc8/0x1b0) from [<c0333) [<c033364c>] (omap_target+0x1b4/0x28c) from [<c032f47c>] (__cpuf) [<c032f47c>] (__cpufreq_driver_target+0x50/0x64) from [<c0331d24) [<c0331d24>] (cpufreq_set+0x78/0x98) from [<c032f6d0>] (store_sc) [<c032f6d0>] (store_scaling_setspeed+0x5c/0x74) from [<c03306a4>) [<c03306a4>] (store+0x58/0x74) from [<c014d868>] (sysfs_write_fi) [<c014d868>] (sysfs_write_file+0x80/0xb4) from [<c00f2c2c>] (vfs) [<c00f2c2c>] (vfs_write+0xa8/0x138) from [<c00f2e9c>] (sys_write) [<c00f2e9c>] (sys_write+0x40/0x6c) from [<c000dd60>] (ret_fast_s) Code: e594300c e792210c e1a01000 e5840004 (e7930002) ---[ end trace 5da3b5167c1ecdda ]--- Reported-by: Kevin Hilman <[email protected]> Acked-by: Marc Zyngier <[email protected]> Tested-by: Kevin Hilman <[email protected]> Signed-off-by: Santosh Shilimkar <[email protected]> Signed-off-by: Russell King <[email protected]>

…S block during isolation for migration commit 0bf380b upstream. When isolating for migration, migration starts at the start of a zone which is not necessarily pageblock aligned. Further, it stops isolating when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally not aligned. This allows isolate_migratepages() to call pfn_to_page() on an invalid PFN which can result in a crash. This was originally reported against a 3.0-based kernel with the following trace in a crash dump. PID: 9902 TASK: d47aecd0 CPU: 0 COMMAND: "memcg_process_s" #0 [d72d3ad0] crash_kexec at c028cfdb #1 [d72d3b24] oops_end at c05c5322 #2 [d72d3b38] __bad_area_nosemaphore at c0227e60 #3 [d72d3bec] bad_area at c0227fb6 #4 [d72d3c00] do_page_fault at c05c72ec #5 [d72d3c80] error_code (via page_fault) at c05c47a4 EAX: 00000000 EBX: 000c0000 ECX: 00000001 EDX: 00000807 EBP: 000c0000 DS: 007b ESI: 00000001 ES: 007b EDI: f3000a80 GS: 6f50 CS: 0060 EIP: c030b15a ERR: ffffffff EFLAGS: 00010002 #6 [d72d3cb4] isolate_migratepages at c030b15a #7 [d72d3d1] zone_watermark_ok at c02d26cb #8 [d72d3d2c] compact_zone at c030b8de #9 [d72d3d68] compact_zone_order at c030bba1 torvalds#10 [d72d3db4] try_to_compact_pages at c030bc84 torvalds#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7 torvalds#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7 torvalds#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97 torvalds#14 [d72d3eb8] alloc_pages_vma at c030a845 torvalds#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb torvalds#16 [d72d3f00] handle_mm_fault at c02f36c6 torvalds#17 [d72d3f30] do_page_fault at c05c70ed torvalds#18 [d72d3fb0] error_code (via page_fault) at c05c47a4 EAX: b71ff000 EBX: 00000001 ECX: 00001600 EDX: 00000431 DS: 007b ESI: 08048950 ES: 007b EDI: bfaa3788 SS: 007b ESP: bfaa36e0 EBP: bfaa3828 GS: 6f50 CS: 0073 EIP: 080487c8 ERR: ffffffff EFLAGS: 00010202 It was also reported by Herbert van den Bergh against 3.1-based kernel with the following snippet from the console log. BUG: unable to handle kernel paging request at 01c00008 IP: [<c0522399>] isolate_migratepages+0x119/0x390 *pdpt = 000000002f7ce001 *pde = 0000000000000000 It is expected that it also affects 3.2.x and current mainline. The problem is that pfn_valid is only called on the first PFN being checked and that PFN is not necessarily aligned. Lets say we have a case like this H = MAX_ORDER_NR_PAGES boundary | = pageblock boundary m = cc->migrate_pfn f = cc->free_pfn o = memory hole H------|------H------|----m-Hoooooo|ooooooH-f----|------H The migrate_pfn is just below a memory hole and the free scanner is beyond the hole. When isolate_migratepages started, it scans from migrate_pfn to migrate_pfn+pageblock_nr_pages which is now in a memory hole. It checks pfn_valid() on the first PFN but then scans into the hole where there are not necessarily valid struct pages. This patch ensures that isolate_migratepages calls pfn_valid when necessary. Reported-by: Herbert van den Bergh <[email protected]> Tested-by: Herbert van den Bergh <[email protected]> Signed-off-by: Mel Gorman <[email protected]> Acked-by: Michal Nazarewicz <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

There is an issue when memcg unregisters events that were attached to the same eventfd: - On the first call mem_cgroup_usage_unregister_event() removes all events attached to a given eventfd, and if there were no events left, thresholds->primary would become NULL; - Since there were several events registered, cgroups core will call mem_cgroup_usage_unregister_event() again, but now kernel will oops, as the function doesn't expect that threshold->primary may be NULL. That's a good question whether mem_cgroup_usage_unregister_event() should actually remove all events in one go, but nowadays it can't do any better as cftype->unregister_event callback doesn't pass any private event-associated cookie. So, let's fix the issue by simply checking for threshold->primary. FWIW, w/o the patch the following oops may be observed: BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 IP: [<ffffffff810be32c>] mem_cgroup_usage_unregister_event+0x9c/0x1f0 Pid: 574, comm: kworker/0:2 Not tainted 3.3.0-rc4+ #9 Bochs Bochs RIP: 0010:[<ffffffff810be32c>] [<ffffffff810be32c>] mem_cgroup_usage_unregister_event+0x9c/0x1f0 RSP: 0018:ffff88001d0b9d60 EFLAGS: 00010246 Process kworker/0:2 (pid: 574, threadinfo ffff88001d0b8000, task ffff88001de91cc0) Call Trace: [<ffffffff8107092b>] cgroup_event_remove+0x2b/0x60 [<ffffffff8103db94>] process_one_work+0x174/0x450 [<ffffffff8103e413>] worker_thread+0x123/0x2d0 Cc: stable <[email protected]> Signed-off-by: Anton Vorontsov <[email protected]> Acked-by: KAMEZAWA Hiroyuki <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Michal Hocko <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

…S block during isolation for migration commit 0bf380b upstream. When isolating for migration, migration starts at the start of a zone which is not necessarily pageblock aligned. Further, it stops isolating when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally not aligned. This allows isolate_migratepages() to call pfn_to_page() on an invalid PFN which can result in a crash. This was originally reported against a 3.0-based kernel with the following trace in a crash dump. PID: 9902 TASK: d47aecd0 CPU: 0 COMMAND: "memcg_process_s" #0 [d72d3ad0] crash_kexec at c028cfdb #1 [d72d3b24] oops_end at c05c5322 #2 [d72d3b38] __bad_area_nosemaphore at c0227e60 #3 [d72d3bec] bad_area at c0227fb6 #4 [d72d3c00] do_page_fault at c05c72ec #5 [d72d3c80] error_code (via page_fault) at c05c47a4 EAX: 00000000 EBX: 000c0000 ECX: 00000001 EDX: 00000807 EBP: 000c0000 DS: 007b ESI: 00000001 ES: 007b EDI: f3000a80 GS: 6f50 CS: 0060 EIP: c030b15a ERR: ffffffff EFLAGS: 00010002 #6 [d72d3cb4] isolate_migratepages at c030b15a #7 [d72d3d1] zone_watermark_ok at c02d26cb #8 [d72d3d2c] compact_zone at c030b8de #9 [d72d3d68] compact_zone_order at c030bba1 torvalds#10 [d72d3db4] try_to_compact_pages at c030bc84 torvalds#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7 torvalds#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7 torvalds#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97 torvalds#14 [d72d3eb8] alloc_pages_vma at c030a845 torvalds#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb torvalds#16 [d72d3f00] handle_mm_fault at c02f36c6 torvalds#17 [d72d3f30] do_page_fault at c05c70ed torvalds#18 [d72d3fb0] error_code (via page_fault) at c05c47a4 EAX: b71ff000 EBX: 00000001 ECX: 00001600 EDX: 00000431 DS: 007b ESI: 08048950 ES: 007b EDI: bfaa3788 SS: 007b ESP: bfaa36e0 EBP: bfaa3828 GS: 6f50 CS: 0073 EIP: 080487c8 ERR: ffffffff EFLAGS: 00010202 It was also reported by Herbert van den Bergh against 3.1-based kernel with the following snippet from the console log. BUG: unable to handle kernel paging request at 01c00008 IP: [<c0522399>] isolate_migratepages+0x119/0x390 *pdpt = 000000002f7ce001 *pde = 0000000000000000 It is expected that it also affects 3.2.x and current mainline. The problem is that pfn_valid is only called on the first PFN being checked and that PFN is not necessarily aligned. Lets say we have a case like this H = MAX_ORDER_NR_PAGES boundary | = pageblock boundary m = cc->migrate_pfn f = cc->free_pfn o = memory hole H------|------H------|----m-Hoooooo|ooooooH-f----|------H The migrate_pfn is just below a memory hole and the free scanner is beyond the hole. When isolate_migratepages started, it scans from migrate_pfn to migrate_pfn+pageblock_nr_pages which is now in a memory hole. It checks pfn_valid() on the first PFN but then scans into the hole where there are not necessarily valid struct pages. This patch ensures that isolate_migratepages calls pfn_valid when necessary. Reported-by: Herbert van den Bergh <[email protected]> Tested-by: Herbert van den Bergh <[email protected]> Signed-off-by: Mel Gorman <[email protected]> Acked-by: Michal Nazarewicz <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

commit 371528c upstream. There is an issue when memcg unregisters events that were attached to the same eventfd: - On the first call mem_cgroup_usage_unregister_event() removes all events attached to a given eventfd, and if there were no events left, thresholds->primary would become NULL; - Since there were several events registered, cgroups core will call mem_cgroup_usage_unregister_event() again, but now kernel will oops, as the function doesn't expect that threshold->primary may be NULL. That's a good question whether mem_cgroup_usage_unregister_event() should actually remove all events in one go, but nowadays it can't do any better as cftype->unregister_event callback doesn't pass any private event-associated cookie. So, let's fix the issue by simply checking for threshold->primary. FWIW, w/o the patch the following oops may be observed: BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 IP: [<ffffffff810be32c>] mem_cgroup_usage_unregister_event+0x9c/0x1f0 Pid: 574, comm: kworker/0:2 Not tainted 3.3.0-rc4+ #9 Bochs Bochs RIP: 0010:[<ffffffff810be32c>] [<ffffffff810be32c>] mem_cgroup_usage_unregister_event+0x9c/0x1f0 RSP: 0018:ffff88001d0b9d60 EFLAGS: 00010246 Process kworker/0:2 (pid: 574, threadinfo ffff88001d0b8000, task ffff88001de91cc0) Call Trace: [<ffffffff8107092b>] cgroup_event_remove+0x2b/0x60 [<ffffffff8103db94>] process_one_work+0x174/0x450 [<ffffffff8103e413>] worker_thread+0x123/0x2d0 Signed-off-by: Anton Vorontsov <[email protected]> Acked-by: KAMEZAWA Hiroyuki <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Michal Hocko <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

…S block during isolation for migration commit 0bf380b upstream. When isolating for migration, migration starts at the start of a zone which is not necessarily pageblock aligned. Further, it stops isolating when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally not aligned. This allows isolate_migratepages() to call pfn_to_page() on an invalid PFN which can result in a crash. This was originally reported against a 3.0-based kernel with the following trace in a crash dump. PID: 9902 TASK: d47aecd0 CPU: 0 COMMAND: "memcg_process_s" #0 [d72d3ad0] crash_kexec at c028cfdb #1 [d72d3b24] oops_end at c05c5322 #2 [d72d3b38] __bad_area_nosemaphore at c0227e60 #3 [d72d3bec] bad_area at c0227fb6 #4 [d72d3c00] do_page_fault at c05c72ec #5 [d72d3c80] error_code (via page_fault) at c05c47a4 EAX: 00000000 EBX: 000c0000 ECX: 00000001 EDX: 00000807 EBP: 000c0000 DS: 007b ESI: 00000001 ES: 007b EDI: f3000a80 GS: 6f50 CS: 0060 EIP: c030b15a ERR: ffffffff EFLAGS: 00010002 #6 [d72d3cb4] isolate_migratepages at c030b15a #7 [d72d3d1] zone_watermark_ok at c02d26cb #8 [d72d3d2c] compact_zone at c030b8de #9 [d72d3d68] compact_zone_order at c030bba1 torvalds#10 [d72d3db4] try_to_compact_pages at c030bc84 torvalds#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7 torvalds#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7 torvalds#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97 torvalds#14 [d72d3eb8] alloc_pages_vma at c030a845 torvalds#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb torvalds#16 [d72d3f00] handle_mm_fault at c02f36c6 torvalds#17 [d72d3f30] do_page_fault at c05c70ed torvalds#18 [d72d3fb0] error_code (via page_fault) at c05c47a4 EAX: b71ff000 EBX: 00000001 ECX: 00001600 EDX: 00000431 DS: 007b ESI: 08048950 ES: 007b EDI: bfaa3788 SS: 007b ESP: bfaa36e0 EBP: bfaa3828 GS: 6f50 CS: 0073 EIP: 080487c8 ERR: ffffffff EFLAGS: 00010202 It was also reported by Herbert van den Bergh against 3.1-based kernel with the following snippet from the console log. BUG: unable to handle kernel paging request at 01c00008 IP: [<c0522399>] isolate_migratepages+0x119/0x390 *pdpt = 000000002f7ce001 *pde = 0000000000000000 It is expected that it also affects 3.2.x and current mainline. The problem is that pfn_valid is only called on the first PFN being checked and that PFN is not necessarily aligned. Lets say we have a case like this H = MAX_ORDER_NR_PAGES boundary | = pageblock boundary m = cc->migrate_pfn f = cc->free_pfn o = memory hole H------|------H------|----m-Hoooooo|ooooooH-f----|------H The migrate_pfn is just below a memory hole and the free scanner is beyond the hole. When isolate_migratepages started, it scans from migrate_pfn to migrate_pfn+pageblock_nr_pages which is now in a memory hole. It checks pfn_valid() on the first PFN but then scans into the hole where there are not necessarily valid struct pages. This patch ensures that isolate_migratepages calls pfn_valid when necessary. Reported-by: Herbert van den Bergh <[email protected]> Tested-by: Herbert van den Bergh <[email protected]> Signed-off-by: Mel Gorman <[email protected]> Acked-by: Michal Nazarewicz <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

commit 371528c upstream. There is an issue when memcg unregisters events that were attached to the same eventfd: - On the first call mem_cgroup_usage_unregister_event() removes all events attached to a given eventfd, and if there were no events left, thresholds->primary would become NULL; - Since there were several events registered, cgroups core will call mem_cgroup_usage_unregister_event() again, but now kernel will oops, as the function doesn't expect that threshold->primary may be NULL. That's a good question whether mem_cgroup_usage_unregister_event() should actually remove all events in one go, but nowadays it can't do any better as cftype->unregister_event callback doesn't pass any private event-associated cookie. So, let's fix the issue by simply checking for threshold->primary. FWIW, w/o the patch the following oops may be observed: BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 IP: [<ffffffff810be32c>] mem_cgroup_usage_unregister_event+0x9c/0x1f0 Pid: 574, comm: kworker/0:2 Not tainted 3.3.0-rc4+ #9 Bochs Bochs RIP: 0010:[<ffffffff810be32c>] [<ffffffff810be32c>] mem_cgroup_usage_unregister_event+0x9c/0x1f0 RSP: 0018:ffff88001d0b9d60 EFLAGS: 00010246 Process kworker/0:2 (pid: 574, threadinfo ffff88001d0b8000, task ffff88001de91cc0) Call Trace: [<ffffffff8107092b>] cgroup_event_remove+0x2b/0x60 [<ffffffff8103db94>] process_one_work+0x174/0x450 [<ffffffff8103e413>] worker_thread+0x123/0x2d0 Signed-off-by: Anton Vorontsov <[email protected]> Acked-by: KAMEZAWA Hiroyuki <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Michal Hocko <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

…S block during isolation for migration commit 0bf380b upstream. When isolating for migration, migration starts at the start of a zone which is not necessarily pageblock aligned. Further, it stops isolating when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally not aligned. This allows isolate_migratepages() to call pfn_to_page() on an invalid PFN which can result in a crash. This was originally reported against a 3.0-based kernel with the following trace in a crash dump. PID: 9902 TASK: d47aecd0 CPU: 0 COMMAND: "memcg_process_s" #0 [d72d3ad0] crash_kexec at c028cfdb #1 [d72d3b24] oops_end at c05c5322 #2 [d72d3b38] __bad_area_nosemaphore at c0227e60 #3 [d72d3bec] bad_area at c0227fb6 #4 [d72d3c00] do_page_fault at c05c72ec #5 [d72d3c80] error_code (via page_fault) at c05c47a4 EAX: 00000000 EBX: 000c0000 ECX: 00000001 EDX: 00000807 EBP: 000c0000 DS: 007b ESI: 00000001 ES: 007b EDI: f3000a80 GS: 6f50 CS: 0060 EIP: c030b15a ERR: ffffffff EFLAGS: 00010002 #6 [d72d3cb4] isolate_migratepages at c030b15a #7 [d72d3d1] zone_watermark_ok at c02d26cb #8 [d72d3d2c] compact_zone at c030b8de #9 [d72d3d68] compact_zone_order at c030bba1 torvalds#10 [d72d3db4] try_to_compact_pages at c030bc84 torvalds#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7 torvalds#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7 torvalds#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97 torvalds#14 [d72d3eb8] alloc_pages_vma at c030a845 torvalds#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb torvalds#16 [d72d3f00] handle_mm_fault at c02f36c6 torvalds#17 [d72d3f30] do_page_fault at c05c70ed torvalds#18 [d72d3fb0] error_code (via page_fault) at c05c47a4 EAX: b71ff000 EBX: 00000001 ECX: 00001600 EDX: 00000431 DS: 007b ESI: 08048950 ES: 007b EDI: bfaa3788 SS: 007b ESP: bfaa36e0 EBP: bfaa3828 GS: 6f50 CS: 0073 EIP: 080487c8 ERR: ffffffff EFLAGS: 00010202 It was also reported by Herbert van den Bergh against 3.1-based kernel with the following snippet from the console log. BUG: unable to handle kernel paging request at 01c00008 IP: [<c0522399>] isolate_migratepages+0x119/0x390 *pdpt = 000000002f7ce001 *pde = 0000000000000000 It is expected that it also affects 3.2.x and current mainline. The problem is that pfn_valid is only called on the first PFN being checked and that PFN is not necessarily aligned. Lets say we have a case like this H = MAX_ORDER_NR_PAGES boundary | = pageblock boundary m = cc->migrate_pfn f = cc->free_pfn o = memory hole H------|------H------|----m-Hoooooo|ooooooH-f----|------H The migrate_pfn is just below a memory hole and the free scanner is beyond the hole. When isolate_migratepages started, it scans from migrate_pfn to migrate_pfn+pageblock_nr_pages which is now in a memory hole. It checks pfn_valid() on the first PFN but then scans into the hole where there are not necessarily valid struct pages. This patch ensures that isolate_migratepages calls pfn_valid when necessary. Reported-by: Herbert van den Bergh <[email protected]> Tested-by: Herbert van den Bergh <[email protected]> Signed-off-by: Mel Gorman <[email protected]> Acked-by: Michal Nazarewicz <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

commit 371528c upstream. There is an issue when memcg unregisters events that were attached to the same eventfd: - On the first call mem_cgroup_usage_unregister_event() removes all events attached to a given eventfd, and if there were no events left, thresholds->primary would become NULL; - Since there were several events registered, cgroups core will call mem_cgroup_usage_unregister_event() again, but now kernel will oops, as the function doesn't expect that threshold->primary may be NULL. That's a good question whether mem_cgroup_usage_unregister_event() should actually remove all events in one go, but nowadays it can't do any better as cftype->unregister_event callback doesn't pass any private event-associated cookie. So, let's fix the issue by simply checking for threshold->primary. FWIW, w/o the patch the following oops may be observed: BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 IP: [<ffffffff810be32c>] mem_cgroup_usage_unregister_event+0x9c/0x1f0 Pid: 574, comm: kworker/0:2 Not tainted 3.3.0-rc4+ #9 Bochs Bochs RIP: 0010:[<ffffffff810be32c>] [<ffffffff810be32c>] mem_cgroup_usage_unregister_event+0x9c/0x1f0 RSP: 0018:ffff88001d0b9d60 EFLAGS: 00010246 Process kworker/0:2 (pid: 574, threadinfo ffff88001d0b8000, task ffff88001de91cc0) Call Trace: [<ffffffff8107092b>] cgroup_event_remove+0x2b/0x60 [<ffffffff8103db94>] process_one_work+0x174/0x450 [<ffffffff8103e413>] worker_thread+0x123/0x2d0 Signed-off-by: Anton Vorontsov <[email protected]> Acked-by: KAMEZAWA Hiroyuki <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Michal Hocko <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

…le_direct_reclaim() commit 6aaced5 upstream. The task sometimes continues looping in throttle_direct_reclaim() because allow_direct_reclaim(pgdat) keeps returning false. #0 [ffff80002cb6f8d0] __switch_to at ffff8000080095ac #1 [ffff80002cb6f900] __schedule at ffff800008abbd1c #2 [ffff80002cb6f990] schedule at ffff800008abc50c #3 [ffff80002cb6f9b0] throttle_direct_reclaim at ffff800008273550 #4 [ffff80002cb6fa20] try_to_free_pages at ffff800008277b68 #5 [ffff80002cb6fae0] __alloc_pages_nodemask at ffff8000082c4660 torvalds#6 [ffff80002cb6fc50] alloc_pages_vma at ffff8000082e4a98 torvalds#7 [ffff80002cb6fca0] do_anonymous_page at ffff80000829f5a8 torvalds#8 [ffff80002cb6fce0] __handle_mm_fault at ffff8000082a5974 torvalds#9 [ffff80002cb6fd90] handle_mm_fault at ffff8000082a5bd4 At this point, the pgdat contains the following two zones: NODE: 4 ZONE: 0 ADDR: ffff00817fffe540 NAME: "DMA32" SIZE: 20480 MIN/LOW/HIGH: 11/28/45 VM_STAT: NR_FREE_PAGES: 359 NR_ZONE_INACTIVE_ANON: 18813 NR_ZONE_ACTIVE_ANON: 0 NR_ZONE_INACTIVE_FILE: 50 NR_ZONE_ACTIVE_FILE: 0 NR_ZONE_UNEVICTABLE: 0 NR_ZONE_WRITE_PENDING: 0 NR_MLOCK: 0 NR_BOUNCE: 0 NR_ZSPAGES: 0 NR_FREE_CMA_PAGES: 0 NODE: 4 ZONE: 1 ADDR: ffff00817fffec00 NAME: "Normal" SIZE: 8454144 PRESENT: 98304 MIN/LOW/HIGH: 68/166/264 VM_STAT: NR_FREE_PAGES: 146 NR_ZONE_INACTIVE_ANON: 94668 NR_ZONE_ACTIVE_ANON: 3 NR_ZONE_INACTIVE_FILE: 735 NR_ZONE_ACTIVE_FILE: 78 NR_ZONE_UNEVICTABLE: 0 NR_ZONE_WRITE_PENDING: 0 NR_MLOCK: 0 NR_BOUNCE: 0 NR_ZSPAGES: 0 NR_FREE_CMA_PAGES: 0 In allow_direct_reclaim(), while processing ZONE_DMA32, the sum of inactive/active file-backed pages calculated in zone_reclaimable_pages() based on the result of zone_page_state_snapshot() is zero. Additionally, since this system lacks swap, the calculation of inactive/ active anonymous pages is skipped. crash> p nr_swap_pages nr_swap_pages = $1937 = { counter = 0 } As a result, ZONE_DMA32 is deemed unreclaimable and skipped, moving on to the processing of the next zone, ZONE_NORMAL, despite ZONE_DMA32 having free pages significantly exceeding the high watermark. The problem is that the pgdat->kswapd_failures hasn't been incremented. crash> px ((struct pglist_data *) 0xffff00817fffe540)->kswapd_failures $1935 = 0x0 This is because the node deemed balanced. The node balancing logic in balance_pgdat() evaluates all zones collectively. If one or more zones (e.g., ZONE_DMA32) have enough free pages to meet their watermarks, the entire node is deemed balanced. This causes balance_pgdat() to exit early before incrementing the kswapd_failures, as it considers the overall memory state acceptable, even though some zones (like ZONE_NORMAL) remain under significant pressure. The patch ensures that zone_reclaimable_pages() includes free pages (NR_FREE_PAGES) in its calculation when no other reclaimable pages are available (e.g., file-backed or anonymous pages). This change prevents zones like ZONE_DMA32, which have sufficient free pages, from being mistakenly deemed unreclaimable. By doing so, the patch ensures proper node balancing, avoids masking pressure on other zones like ZONE_NORMAL, and prevents infinite loops in throttle_direct_reclaim() caused by allow_direct_reclaim(pgdat) repeatedly returning false. The kernel hangs due to a task stuck in throttle_direct_reclaim(), caused by a node being incorrectly deemed balanced despite pressure in certain zones, such as ZONE_NORMAL. This issue arises from zone_reclaimable_pages() returning 0 for zones without reclaimable file- backed or anonymous pages, causing zones like ZONE_DMA32 with sufficient free pages to be skipped. The lack of swap or reclaimable pages results in ZONE_DMA32 being ignored during reclaim, masking pressure in other zones. Consequently, pgdat->kswapd_failures remains 0 in balance_pgdat(), preventing fallback mechanisms in allow_direct_reclaim() from being triggered, leading to an infinite loop in throttle_direct_reclaim(). This patch modifies zone_reclaimable_pages() to account for free pages (NR_FREE_PAGES) when no other reclaimable pages exist. This ensures zones with sufficient free pages are not skipped, enabling proper balancing and reclaim behavior. [[email protected]: coding-style cleanups] Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Fixes: 5a1c84b ("mm: remove reclaim and compaction retry approximations") Signed-off-by: Seiji Nishikawa <[email protected]> Cc: Mel Gorman <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

This fixes the following hard lockup in isolate_lru_folios() during memory reclaim. If the LRU mostly contains ineligible folios this may trigger watchdog. watchdog: Watchdog detected hard LOCKUP on cpu 173 RIP: 0010:native_queued_spin_lock_slowpath+0x255/0x2a0 Call Trace: _raw_spin_lock_irqsave+0x31/0x40 folio_lruvec_lock_irqsave+0x5f/0x90 folio_batch_move_lru+0x91/0x150 lru_add_drain_per_cpu+0x1c/0x40 process_one_work+0x17d/0x350 worker_thread+0x27b/0x3a0 kthread+0xe8/0x120 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1b/0x30 lruvec->lru_lock owner： PID: 2865 TASK: ffff888139214d40 CPU: 40 COMMAND: "kswapd0" #0 [fffffe0000945e60] crash_nmi_callback at ffffffffa567a555 #1 [fffffe0000945e68] nmi_handle at ffffffffa563b171 #2 [fffffe0000945eb0] default_do_nmi at ffffffffa6575920 #3 [fffffe0000945ed0] exc_nmi at ffffffffa6575af4 #4 [fffffe0000945ef0] end_repeat_nmi at ffffffffa6601dde [exception RIP: isolate_lru_folios+403] RIP: ffffffffa597df53 RSP: ffffc90006fb7c28 RFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffc90006fb7c60 RCX: ffffea04a2196f88 RDX: ffffc90006fb7c60 RSI: ffffc90006fb7c60 RDI: ffffea04a2197048 RBP: ffff88812cbd3010 R8: ffffea04a2197008 R9: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea04a2197008 R13: ffffea04a2197048 R14: ffffc90006fb7de8 R15: 0000000003e3e937 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 <NMI exception stack> #5 [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 torvalds#6 [ffffc90006fb7cf8] shrink_active_list at ffffffffa597f788 torvalds#7 [ffffc90006fb7da8] balance_pgdat at ffffffffa5986db0 torvalds#8 [ffffc90006fb7ec0] kswapd at ffffffffa5987354 torvalds#9 [ffffc90006fb7ef8] kthread at ffffffffa5748238 crash> Scenario: User processe are requesting a large amount of memory and keep page active. Then a module continuously requests memory from ZONE_DMA32 area. Memory reclaim will be triggered due to ZONE_DMA32 watermark alarm reached. However pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. Reproduce: Terminal 1: Construct to continuously increase pages active(anon). mkdir /tmp/memory mount -t tmpfs -o size=1024000M tmpfs /tmp/memory dd if=/dev/zero of=/tmp/memory/block bs=4M tail /tmp/memory/block Terminal 2: vmstat -a 1 active will increase. procs ---memory--- ---swap-- ---io---- -system-- ---cpu--- ... r b swpd free inact active si so bi bo 1 0 0 1445623076 45898836 83646008 0 0 0 1 0 0 1445623076 43450228 86094616 0 0 0 1 0 0 1445623076 41003480 88541364 0 0 0 1 0 0 1445623076 38557088 90987756 0 0 0 1 0 0 1445623076 36109688 93435156 0 0 0 1 0 0 1445619552 33663256 95881632 0 0 0 1 0 0 1445619804 31217140 98327792 0 0 0 1 0 0 1445619804 28769988 100774944 0 0 0 1 0 0 1445619804 26322348 103222584 0 0 0 1 0 0 1445619804 23875592 105669340 0 0 0 cat /proc/meminfo | head Active(anon) increase. MemTotal: 1579941036 kB MemFree: 1445618500 kB MemAvailable: 1453013224 kB Buffers: 6516 kB Cached: 128653956 kB SwapCached: 0 kB Active: 118110812 kB Inactive: 11436620 kB Active(anon): 115345744 kB Inactive(anon): 945292 kB When the Active(anon) is 115345744 kB, insmod module triggers the ZONE_DMA32 watermark. perf record -e vmscan:mm_vmscan_lru_isolate -aR perf script isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=2 nr_skipped=2 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=29 nr_skipped=29 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon See nr_scanned=28835844. 28835844 * 4k = 115343376KB approximately equal to 115345744 kB. If increase Active(anon) to 1000G then insmod module triggers the ZONE_DMA32 watermark. hard lockup will occur. In my device nr_scanned = 0000000003e3e937 when hard lockup. Convert to memory size 0x0000000003e3e937 * 4KB = 261072092 KB. [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 ffffc90006fb7c30: 0000000000000020 0000000000000000 ffffc90006fb7c40: ffffc90006fb7d40 ffff88812cbd3000 ffffc90006fb7c50: ffffc90006fb7d30 0000000106fb7de8 ffffc90006fb7c60: ffffea04a2197008 ffffea0006ed4a48 ffffc90006fb7c70: 0000000000000000 0000000000000000 ffffc90006fb7c80: 0000000000000000 0000000000000000 ffffc90006fb7c90: 0000000000000000 0000000000000000 ffffc90006fb7ca0: 0000000000000000 0000000003e3e937 ffffc90006fb7cb0: 0000000000000000 0000000000000000 ffffc90006fb7cc0: 8d7c0b56b7874b00 ffff88812cbd3000 About the Fixes: Why did it take eight years to be discovered? The problem requires the following conditions to occur: 1. The device memory should be large enough. 2. Pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. 3. The memory in ZONE_DMA32 needs to reach the watermark. If the memory is not large enough, or if the usage design of ZONE_DMA32 area memory is reasonable, this problem is difficult to detect. notes: The problem is most likely to occur in ZONE_DMA32 and ZONE_NORMAL, but other suitable scenarios may also trigger the problem. Link: https://lkml.kernel.org/r/[email protected] Fixes: b2e1875 ("mm, vmscan: begin reclaiming pages on a per-node basis") Signed-off-by: liuye <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Yang Shi <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

…le_direct_reclaim() commit 6aaced5 upstream. The task sometimes continues looping in throttle_direct_reclaim() because allow_direct_reclaim(pgdat) keeps returning false. #0 [ffff80002cb6f8d0] __switch_to at ffff8000080095ac #1 [ffff80002cb6f900] __schedule at ffff800008abbd1c #2 [ffff80002cb6f990] schedule at ffff800008abc50c #3 [ffff80002cb6f9b0] throttle_direct_reclaim at ffff800008273550 #4 [ffff80002cb6fa20] try_to_free_pages at ffff800008277b68 #5 [ffff80002cb6fae0] __alloc_pages_nodemask at ffff8000082c4660 torvalds#6 [ffff80002cb6fc50] alloc_pages_vma at ffff8000082e4a98 torvalds#7 [ffff80002cb6fca0] do_anonymous_page at ffff80000829f5a8 torvalds#8 [ffff80002cb6fce0] __handle_mm_fault at ffff8000082a5974 torvalds#9 [ffff80002cb6fd90] handle_mm_fault at ffff8000082a5bd4 At this point, the pgdat contains the following two zones: NODE: 4 ZONE: 0 ADDR: ffff00817fffe540 NAME: "DMA32" SIZE: 20480 MIN/LOW/HIGH: 11/28/45 VM_STAT: NR_FREE_PAGES: 359 NR_ZONE_INACTIVE_ANON: 18813 NR_ZONE_ACTIVE_ANON: 0 NR_ZONE_INACTIVE_FILE: 50 NR_ZONE_ACTIVE_FILE: 0 NR_ZONE_UNEVICTABLE: 0 NR_ZONE_WRITE_PENDING: 0 NR_MLOCK: 0 NR_BOUNCE: 0 NR_ZSPAGES: 0 NR_FREE_CMA_PAGES: 0 NODE: 4 ZONE: 1 ADDR: ffff00817fffec00 NAME: "Normal" SIZE: 8454144 PRESENT: 98304 MIN/LOW/HIGH: 68/166/264 VM_STAT: NR_FREE_PAGES: 146 NR_ZONE_INACTIVE_ANON: 94668 NR_ZONE_ACTIVE_ANON: 3 NR_ZONE_INACTIVE_FILE: 735 NR_ZONE_ACTIVE_FILE: 78 NR_ZONE_UNEVICTABLE: 0 NR_ZONE_WRITE_PENDING: 0 NR_MLOCK: 0 NR_BOUNCE: 0 NR_ZSPAGES: 0 NR_FREE_CMA_PAGES: 0 In allow_direct_reclaim(), while processing ZONE_DMA32, the sum of inactive/active file-backed pages calculated in zone_reclaimable_pages() based on the result of zone_page_state_snapshot() is zero. Additionally, since this system lacks swap, the calculation of inactive/ active anonymous pages is skipped. crash> p nr_swap_pages nr_swap_pages = $1937 = { counter = 0 } As a result, ZONE_DMA32 is deemed unreclaimable and skipped, moving on to the processing of the next zone, ZONE_NORMAL, despite ZONE_DMA32 having free pages significantly exceeding the high watermark. The problem is that the pgdat->kswapd_failures hasn't been incremented. crash> px ((struct pglist_data *) 0xffff00817fffe540)->kswapd_failures $1935 = 0x0 This is because the node deemed balanced. The node balancing logic in balance_pgdat() evaluates all zones collectively. If one or more zones (e.g., ZONE_DMA32) have enough free pages to meet their watermarks, the entire node is deemed balanced. This causes balance_pgdat() to exit early before incrementing the kswapd_failures, as it considers the overall memory state acceptable, even though some zones (like ZONE_NORMAL) remain under significant pressure. The patch ensures that zone_reclaimable_pages() includes free pages (NR_FREE_PAGES) in its calculation when no other reclaimable pages are available (e.g., file-backed or anonymous pages). This change prevents zones like ZONE_DMA32, which have sufficient free pages, from being mistakenly deemed unreclaimable. By doing so, the patch ensures proper node balancing, avoids masking pressure on other zones like ZONE_NORMAL, and prevents infinite loops in throttle_direct_reclaim() caused by allow_direct_reclaim(pgdat) repeatedly returning false. The kernel hangs due to a task stuck in throttle_direct_reclaim(), caused by a node being incorrectly deemed balanced despite pressure in certain zones, such as ZONE_NORMAL. This issue arises from zone_reclaimable_pages() returning 0 for zones without reclaimable file- backed or anonymous pages, causing zones like ZONE_DMA32 with sufficient free pages to be skipped. The lack of swap or reclaimable pages results in ZONE_DMA32 being ignored during reclaim, masking pressure in other zones. Consequently, pgdat->kswapd_failures remains 0 in balance_pgdat(), preventing fallback mechanisms in allow_direct_reclaim() from being triggered, leading to an infinite loop in throttle_direct_reclaim(). This patch modifies zone_reclaimable_pages() to account for free pages (NR_FREE_PAGES) when no other reclaimable pages exist. This ensures zones with sufficient free pages are not skipped, enabling proper balancing and reclaim behavior. [[email protected]: coding-style cleanups] Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Fixes: 5a1c84b ("mm: remove reclaim and compaction retry approximations") Signed-off-by: Seiji Nishikawa <[email protected]> Cc: Mel Gorman <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

This fixes the following hard lockup in isolate_lru_folios() during memory reclaim. If the LRU mostly contains ineligible folios this may trigger watchdog. watchdog: Watchdog detected hard LOCKUP on cpu 173 RIP: 0010:native_queued_spin_lock_slowpath+0x255/0x2a0 Call Trace: _raw_spin_lock_irqsave+0x31/0x40 folio_lruvec_lock_irqsave+0x5f/0x90 folio_batch_move_lru+0x91/0x150 lru_add_drain_per_cpu+0x1c/0x40 process_one_work+0x17d/0x350 worker_thread+0x27b/0x3a0 kthread+0xe8/0x120 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1b/0x30 lruvec->lru_lock owner： PID: 2865 TASK: ffff888139214d40 CPU: 40 COMMAND: "kswapd0" #0 [fffffe0000945e60] crash_nmi_callback at ffffffffa567a555 #1 [fffffe0000945e68] nmi_handle at ffffffffa563b171 #2 [fffffe0000945eb0] default_do_nmi at ffffffffa6575920 #3 [fffffe0000945ed0] exc_nmi at ffffffffa6575af4 #4 [fffffe0000945ef0] end_repeat_nmi at ffffffffa6601dde [exception RIP: isolate_lru_folios+403] RIP: ffffffffa597df53 RSP: ffffc90006fb7c28 RFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffc90006fb7c60 RCX: ffffea04a2196f88 RDX: ffffc90006fb7c60 RSI: ffffc90006fb7c60 RDI: ffffea04a2197048 RBP: ffff88812cbd3010 R8: ffffea04a2197008 R9: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea04a2197008 R13: ffffea04a2197048 R14: ffffc90006fb7de8 R15: 0000000003e3e937 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 <NMI exception stack> #5 [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 torvalds#6 [ffffc90006fb7cf8] shrink_active_list at ffffffffa597f788 torvalds#7 [ffffc90006fb7da8] balance_pgdat at ffffffffa5986db0 torvalds#8 [ffffc90006fb7ec0] kswapd at ffffffffa5987354 torvalds#9 [ffffc90006fb7ef8] kthread at ffffffffa5748238 crash> Scenario: User processe are requesting a large amount of memory and keep page active. Then a module continuously requests memory from ZONE_DMA32 area. Memory reclaim will be triggered due to ZONE_DMA32 watermark alarm reached. However pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. Reproduce: Terminal 1: Construct to continuously increase pages active(anon). mkdir /tmp/memory mount -t tmpfs -o size=1024000M tmpfs /tmp/memory dd if=/dev/zero of=/tmp/memory/block bs=4M tail /tmp/memory/block Terminal 2: vmstat -a 1 active will increase. procs ---memory--- ---swap-- ---io---- -system-- ---cpu--- ... r b swpd free inact active si so bi bo 1 0 0 1445623076 45898836 83646008 0 0 0 1 0 0 1445623076 43450228 86094616 0 0 0 1 0 0 1445623076 41003480 88541364 0 0 0 1 0 0 1445623076 38557088 90987756 0 0 0 1 0 0 1445623076 36109688 93435156 0 0 0 1 0 0 1445619552 33663256 95881632 0 0 0 1 0 0 1445619804 31217140 98327792 0 0 0 1 0 0 1445619804 28769988 100774944 0 0 0 1 0 0 1445619804 26322348 103222584 0 0 0 1 0 0 1445619804 23875592 105669340 0 0 0 cat /proc/meminfo | head Active(anon) increase. MemTotal: 1579941036 kB MemFree: 1445618500 kB MemAvailable: 1453013224 kB Buffers: 6516 kB Cached: 128653956 kB SwapCached: 0 kB Active: 118110812 kB Inactive: 11436620 kB Active(anon): 115345744 kB Inactive(anon): 945292 kB When the Active(anon) is 115345744 kB, insmod module triggers the ZONE_DMA32 watermark. perf record -e vmscan:mm_vmscan_lru_isolate -aR perf script isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=2 nr_skipped=2 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=29 nr_skipped=29 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon See nr_scanned=28835844. 28835844 * 4k = 115343376KB approximately equal to 115345744 kB. If increase Active(anon) to 1000G then insmod module triggers the ZONE_DMA32 watermark. hard lockup will occur. In my device nr_scanned = 0000000003e3e937 when hard lockup. Convert to memory size 0x0000000003e3e937 * 4KB = 261072092 KB. [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 ffffc90006fb7c30: 0000000000000020 0000000000000000 ffffc90006fb7c40: ffffc90006fb7d40 ffff88812cbd3000 ffffc90006fb7c50: ffffc90006fb7d30 0000000106fb7de8 ffffc90006fb7c60: ffffea04a2197008 ffffea0006ed4a48 ffffc90006fb7c70: 0000000000000000 0000000000000000 ffffc90006fb7c80: 0000000000000000 0000000000000000 ffffc90006fb7c90: 0000000000000000 0000000000000000 ffffc90006fb7ca0: 0000000000000000 0000000003e3e937 ffffc90006fb7cb0: 0000000000000000 0000000000000000 ffffc90006fb7cc0: 8d7c0b56b7874b00 ffff88812cbd3000 About the Fixes: Why did it take eight years to be discovered? The problem requires the following conditions to occur: 1. The device memory should be large enough. 2. Pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. 3. The memory in ZONE_DMA32 needs to reach the watermark. If the memory is not large enough, or if the usage design of ZONE_DMA32 area memory is reasonable, this problem is difficult to detect. notes: The problem is most likely to occur in ZONE_DMA32 and ZONE_NORMAL, but other suitable scenarios may also trigger the problem. Link: https://lkml.kernel.org/r/[email protected] Fixes: b2e1875 ("mm, vmscan: begin reclaiming pages on a per-node basis") Signed-off-by: liuye <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Yang Shi <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

…le_direct_reclaim() commit 6aaced5 upstream. The task sometimes continues looping in throttle_direct_reclaim() because allow_direct_reclaim(pgdat) keeps returning false. #0 [ffff80002cb6f8d0] __switch_to at ffff8000080095ac #1 [ffff80002cb6f900] __schedule at ffff800008abbd1c #2 [ffff80002cb6f990] schedule at ffff800008abc50c #3 [ffff80002cb6f9b0] throttle_direct_reclaim at ffff800008273550 #4 [ffff80002cb6fa20] try_to_free_pages at ffff800008277b68 #5 [ffff80002cb6fae0] __alloc_pages_nodemask at ffff8000082c4660 torvalds#6 [ffff80002cb6fc50] alloc_pages_vma at ffff8000082e4a98 torvalds#7 [ffff80002cb6fca0] do_anonymous_page at ffff80000829f5a8 torvalds#8 [ffff80002cb6fce0] __handle_mm_fault at ffff8000082a5974 torvalds#9 [ffff80002cb6fd90] handle_mm_fault at ffff8000082a5bd4 At this point, the pgdat contains the following two zones: NODE: 4 ZONE: 0 ADDR: ffff00817fffe540 NAME: "DMA32" SIZE: 20480 MIN/LOW/HIGH: 11/28/45 VM_STAT: NR_FREE_PAGES: 359 NR_ZONE_INACTIVE_ANON: 18813 NR_ZONE_ACTIVE_ANON: 0 NR_ZONE_INACTIVE_FILE: 50 NR_ZONE_ACTIVE_FILE: 0 NR_ZONE_UNEVICTABLE: 0 NR_ZONE_WRITE_PENDING: 0 NR_MLOCK: 0 NR_BOUNCE: 0 NR_ZSPAGES: 0 NR_FREE_CMA_PAGES: 0 NODE: 4 ZONE: 1 ADDR: ffff00817fffec00 NAME: "Normal" SIZE: 8454144 PRESENT: 98304 MIN/LOW/HIGH: 68/166/264 VM_STAT: NR_FREE_PAGES: 146 NR_ZONE_INACTIVE_ANON: 94668 NR_ZONE_ACTIVE_ANON: 3 NR_ZONE_INACTIVE_FILE: 735 NR_ZONE_ACTIVE_FILE: 78 NR_ZONE_UNEVICTABLE: 0 NR_ZONE_WRITE_PENDING: 0 NR_MLOCK: 0 NR_BOUNCE: 0 NR_ZSPAGES: 0 NR_FREE_CMA_PAGES: 0 In allow_direct_reclaim(), while processing ZONE_DMA32, the sum of inactive/active file-backed pages calculated in zone_reclaimable_pages() based on the result of zone_page_state_snapshot() is zero. Additionally, since this system lacks swap, the calculation of inactive/ active anonymous pages is skipped. crash> p nr_swap_pages nr_swap_pages = $1937 = { counter = 0 } As a result, ZONE_DMA32 is deemed unreclaimable and skipped, moving on to the processing of the next zone, ZONE_NORMAL, despite ZONE_DMA32 having free pages significantly exceeding the high watermark. The problem is that the pgdat->kswapd_failures hasn't been incremented. crash> px ((struct pglist_data *) 0xffff00817fffe540)->kswapd_failures $1935 = 0x0 This is because the node deemed balanced. The node balancing logic in balance_pgdat() evaluates all zones collectively. If one or more zones (e.g., ZONE_DMA32) have enough free pages to meet their watermarks, the entire node is deemed balanced. This causes balance_pgdat() to exit early before incrementing the kswapd_failures, as it considers the overall memory state acceptable, even though some zones (like ZONE_NORMAL) remain under significant pressure. The patch ensures that zone_reclaimable_pages() includes free pages (NR_FREE_PAGES) in its calculation when no other reclaimable pages are available (e.g., file-backed or anonymous pages). This change prevents zones like ZONE_DMA32, which have sufficient free pages, from being mistakenly deemed unreclaimable. By doing so, the patch ensures proper node balancing, avoids masking pressure on other zones like ZONE_NORMAL, and prevents infinite loops in throttle_direct_reclaim() caused by allow_direct_reclaim(pgdat) repeatedly returning false. The kernel hangs due to a task stuck in throttle_direct_reclaim(), caused by a node being incorrectly deemed balanced despite pressure in certain zones, such as ZONE_NORMAL. This issue arises from zone_reclaimable_pages() returning 0 for zones without reclaimable file- backed or anonymous pages, causing zones like ZONE_DMA32 with sufficient free pages to be skipped. The lack of swap or reclaimable pages results in ZONE_DMA32 being ignored during reclaim, masking pressure in other zones. Consequently, pgdat->kswapd_failures remains 0 in balance_pgdat(), preventing fallback mechanisms in allow_direct_reclaim() from being triggered, leading to an infinite loop in throttle_direct_reclaim(). This patch modifies zone_reclaimable_pages() to account for free pages (NR_FREE_PAGES) when no other reclaimable pages exist. This ensures zones with sufficient free pages are not skipped, enabling proper balancing and reclaim behavior. [[email protected]: coding-style cleanups] Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Fixes: 5a1c84b ("mm: remove reclaim and compaction retry approximations") Signed-off-by: Seiji Nishikawa <[email protected]> Cc: Mel Gorman <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

This fixes the following hard lockup in isolate_lru_folios() during memory reclaim. If the LRU mostly contains ineligible folios this may trigger watchdog. watchdog: Watchdog detected hard LOCKUP on cpu 173 RIP: 0010:native_queued_spin_lock_slowpath+0x255/0x2a0 Call Trace: _raw_spin_lock_irqsave+0x31/0x40 folio_lruvec_lock_irqsave+0x5f/0x90 folio_batch_move_lru+0x91/0x150 lru_add_drain_per_cpu+0x1c/0x40 process_one_work+0x17d/0x350 worker_thread+0x27b/0x3a0 kthread+0xe8/0x120 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1b/0x30 lruvec->lru_lock owner： PID: 2865 TASK: ffff888139214d40 CPU: 40 COMMAND: "kswapd0" #0 [fffffe0000945e60] crash_nmi_callback at ffffffffa567a555 #1 [fffffe0000945e68] nmi_handle at ffffffffa563b171 #2 [fffffe0000945eb0] default_do_nmi at ffffffffa6575920 #3 [fffffe0000945ed0] exc_nmi at ffffffffa6575af4 #4 [fffffe0000945ef0] end_repeat_nmi at ffffffffa6601dde [exception RIP: isolate_lru_folios+403] RIP: ffffffffa597df53 RSP: ffffc90006fb7c28 RFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffc90006fb7c60 RCX: ffffea04a2196f88 RDX: ffffc90006fb7c60 RSI: ffffc90006fb7c60 RDI: ffffea04a2197048 RBP: ffff88812cbd3010 R8: ffffea04a2197008 R9: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea04a2197008 R13: ffffea04a2197048 R14: ffffc90006fb7de8 R15: 0000000003e3e937 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 <NMI exception stack> #5 [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 torvalds#6 [ffffc90006fb7cf8] shrink_active_list at ffffffffa597f788 torvalds#7 [ffffc90006fb7da8] balance_pgdat at ffffffffa5986db0 torvalds#8 [ffffc90006fb7ec0] kswapd at ffffffffa5987354 torvalds#9 [ffffc90006fb7ef8] kthread at ffffffffa5748238 crash> Scenario: User processe are requesting a large amount of memory and keep page active. Then a module continuously requests memory from ZONE_DMA32 area. Memory reclaim will be triggered due to ZONE_DMA32 watermark alarm reached. However pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. Reproduce: Terminal 1: Construct to continuously increase pages active(anon). mkdir /tmp/memory mount -t tmpfs -o size=1024000M tmpfs /tmp/memory dd if=/dev/zero of=/tmp/memory/block bs=4M tail /tmp/memory/block Terminal 2: vmstat -a 1 active will increase. procs ---memory--- ---swap-- ---io---- -system-- ---cpu--- ... r b swpd free inact active si so bi bo 1 0 0 1445623076 45898836 83646008 0 0 0 1 0 0 1445623076 43450228 86094616 0 0 0 1 0 0 1445623076 41003480 88541364 0 0 0 1 0 0 1445623076 38557088 90987756 0 0 0 1 0 0 1445623076 36109688 93435156 0 0 0 1 0 0 1445619552 33663256 95881632 0 0 0 1 0 0 1445619804 31217140 98327792 0 0 0 1 0 0 1445619804 28769988 100774944 0 0 0 1 0 0 1445619804 26322348 103222584 0 0 0 1 0 0 1445619804 23875592 105669340 0 0 0 cat /proc/meminfo | head Active(anon) increase. MemTotal: 1579941036 kB MemFree: 1445618500 kB MemAvailable: 1453013224 kB Buffers: 6516 kB Cached: 128653956 kB SwapCached: 0 kB Active: 118110812 kB Inactive: 11436620 kB Active(anon): 115345744 kB Inactive(anon): 945292 kB When the Active(anon) is 115345744 kB, insmod module triggers the ZONE_DMA32 watermark. perf record -e vmscan:mm_vmscan_lru_isolate -aR perf script isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=2 nr_skipped=2 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=29 nr_skipped=29 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon See nr_scanned=28835844. 28835844 * 4k = 115343376KB approximately equal to 115345744 kB. If increase Active(anon) to 1000G then insmod module triggers the ZONE_DMA32 watermark. hard lockup will occur. In my device nr_scanned = 0000000003e3e937 when hard lockup. Convert to memory size 0x0000000003e3e937 * 4KB = 261072092 KB. [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 ffffc90006fb7c30: 0000000000000020 0000000000000000 ffffc90006fb7c40: ffffc90006fb7d40 ffff88812cbd3000 ffffc90006fb7c50: ffffc90006fb7d30 0000000106fb7de8 ffffc90006fb7c60: ffffea04a2197008 ffffea0006ed4a48 ffffc90006fb7c70: 0000000000000000 0000000000000000 ffffc90006fb7c80: 0000000000000000 0000000000000000 ffffc90006fb7c90: 0000000000000000 0000000000000000 ffffc90006fb7ca0: 0000000000000000 0000000003e3e937 ffffc90006fb7cb0: 0000000000000000 0000000000000000 ffffc90006fb7cc0: 8d7c0b56b7874b00 ffff88812cbd3000 About the Fixes: Why did it take eight years to be discovered? The problem requires the following conditions to occur: 1. The device memory should be large enough. 2. Pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. 3. The memory in ZONE_DMA32 needs to reach the watermark. If the memory is not large enough, or if the usage design of ZONE_DMA32 area memory is reasonable, this problem is difficult to detect. notes: The problem is most likely to occur in ZONE_DMA32 and ZONE_NORMAL, but other suitable scenarios may also trigger the problem. Link: https://lkml.kernel.org/r/[email protected] Fixes: b2e1875 ("mm, vmscan: begin reclaiming pages on a per-node basis") Signed-off-by: liuye <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Yang Shi <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Chase reports that their tester complaints about a locking context mismatch: ============================= [ BUG: Invalid wait context ] 6.13.0-rc1-gf137f14b7ccb-dirty torvalds#9 Not tainted ----------------------------- syz.1.25198/182604 is trying to lock: ffff88805e66a358 (&ctx->timeout_lock){-.-.}-{3:3}, at: spin_lock_irq include/linux/spinlock.h:376 [inline] ffff88805e66a358 (&ctx->timeout_lock){-.-.}-{3:3}, at: io_match_task_safe io_uring/io_uring.c:218 [inline] ffff88805e66a358 (&ctx->timeout_lock){-.-.}-{3:3}, at: io_match_task_safe+0x187/0x250 io_uring/io_uring.c:204 other info that might help us debug this: context-{5:5} 1 lock held by syz.1.25198/182604: #0: ffff88802b7d48c0 (&acct->lock){+.+.}-{2:2}, at: io_acct_cancel_pending_work+0x2d/0x6b0 io_uring/io-wq.c:1049 stack backtrace: CPU: 0 UID: 0 PID: 182604 Comm: syz.1.25198 Not tainted 6.13.0-rc1-gf137f14b7ccb-dirty torvalds#9 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x82/0xd0 lib/dump_stack.c:120 print_lock_invalid_wait_context kernel/locking/lockdep.c:4826 [inline] check_wait_context kernel/locking/lockdep.c:4898 [inline] __lock_acquire+0x883/0x3c80 kernel/locking/lockdep.c:5176 lock_acquire.part.0+0x11b/0x370 kernel/locking/lockdep.c:5849 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0x36/0x50 kernel/locking/spinlock.c:170 spin_lock_irq include/linux/spinlock.h:376 [inline] io_match_task_safe io_uring/io_uring.c:218 [inline] io_match_task_safe+0x187/0x250 io_uring/io_uring.c:204 io_acct_cancel_pending_work+0xb8/0x6b0 io_uring/io-wq.c:1052 io_wq_cancel_pending_work io_uring/io-wq.c:1074 [inline] io_wq_cancel_cb+0xb0/0x390 io_uring/io-wq.c:1112 io_uring_try_cancel_requests+0x15e/0xd70 io_uring/io_uring.c:3062 io_uring_cancel_generic+0x6ec/0x8c0 io_uring/io_uring.c:3140 io_uring_files_cancel include/linux/io_uring.h:20 [inline] do_exit+0x494/0x27a0 kernel/exit.c:894 do_group_exit+0xb3/0x250 kernel/exit.c:1087 get_signal+0x1d77/0x1ef0 kernel/signal.c:3017 arch_do_signal_or_restart+0x79/0x5b0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xd8/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f which is because io_uring has ctx->timeout_lock nesting inside the io-wq acct lock, the latter of which is used from inside the scheduler and hence is a raw spinlock, while the former is a "normal" spinlock and can hence be sleeping on PREEMPT_RT. Change ctx->timeout_lock to be a raw spinlock to solve this nesting dependency on PREEMPT_RT=y. Reported-by: chase xd <[email protected]> Signed-off-by: Jens Axboe <[email protected]>

…le_direct_reclaim() The task sometimes continues looping in throttle_direct_reclaim() because allow_direct_reclaim(pgdat) keeps returning false. #0 [ffff80002cb6f8d0] __switch_to at ffff8000080095ac #1 [ffff80002cb6f900] __schedule at ffff800008abbd1c #2 [ffff80002cb6f990] schedule at ffff800008abc50c #3 [ffff80002cb6f9b0] throttle_direct_reclaim at ffff800008273550 #4 [ffff80002cb6fa20] try_to_free_pages at ffff800008277b68 #5 [ffff80002cb6fae0] __alloc_pages_nodemask at ffff8000082c4660 torvalds#6 [ffff80002cb6fc50] alloc_pages_vma at ffff8000082e4a98 torvalds#7 [ffff80002cb6fca0] do_anonymous_page at ffff80000829f5a8 torvalds#8 [ffff80002cb6fce0] __handle_mm_fault at ffff8000082a5974 torvalds#9 [ffff80002cb6fd90] handle_mm_fault at ffff8000082a5bd4 At this point, the pgdat contains the following two zones: NODE: 4 ZONE: 0 ADDR: ffff00817fffe540 NAME: "DMA32" SIZE: 20480 MIN/LOW/HIGH: 11/28/45 VM_STAT: NR_FREE_PAGES: 359 NR_ZONE_INACTIVE_ANON: 18813 NR_ZONE_ACTIVE_ANON: 0 NR_ZONE_INACTIVE_FILE: 50 NR_ZONE_ACTIVE_FILE: 0 NR_ZONE_UNEVICTABLE: 0 NR_ZONE_WRITE_PENDING: 0 NR_MLOCK: 0 NR_BOUNCE: 0 NR_ZSPAGES: 0 NR_FREE_CMA_PAGES: 0 NODE: 4 ZONE: 1 ADDR: ffff00817fffec00 NAME: "Normal" SIZE: 8454144 PRESENT: 98304 MIN/LOW/HIGH: 68/166/264 VM_STAT: NR_FREE_PAGES: 146 NR_ZONE_INACTIVE_ANON: 94668 NR_ZONE_ACTIVE_ANON: 3 NR_ZONE_INACTIVE_FILE: 735 NR_ZONE_ACTIVE_FILE: 78 NR_ZONE_UNEVICTABLE: 0 NR_ZONE_WRITE_PENDING: 0 NR_MLOCK: 0 NR_BOUNCE: 0 NR_ZSPAGES: 0 NR_FREE_CMA_PAGES: 0 In allow_direct_reclaim(), while processing ZONE_DMA32, the sum of inactive/active file-backed pages calculated in zone_reclaimable_pages() based on the result of zone_page_state_snapshot() is zero. Additionally, since this system lacks swap, the calculation of inactive/ active anonymous pages is skipped. crash> p nr_swap_pages nr_swap_pages = $1937 = { counter = 0 } As a result, ZONE_DMA32 is deemed unreclaimable and skipped, moving on to the processing of the next zone, ZONE_NORMAL, despite ZONE_DMA32 having free pages significantly exceeding the high watermark. The problem is that the pgdat->kswapd_failures hasn't been incremented. crash> px ((struct pglist_data *) 0xffff00817fffe540)->kswapd_failures $1935 = 0x0 This is because the node deemed balanced. The node balancing logic in balance_pgdat() evaluates all zones collectively. If one or more zones (e.g., ZONE_DMA32) have enough free pages to meet their watermarks, the entire node is deemed balanced. This causes balance_pgdat() to exit early before incrementing the kswapd_failures, as it considers the overall memory state acceptable, even though some zones (like ZONE_NORMAL) remain under significant pressure. The patch ensures that zone_reclaimable_pages() includes free pages (NR_FREE_PAGES) in its calculation when no other reclaimable pages are available (e.g., file-backed or anonymous pages). This change prevents zones like ZONE_DMA32, which have sufficient free pages, from being mistakenly deemed unreclaimable. By doing so, the patch ensures proper node balancing, avoids masking pressure on other zones like ZONE_NORMAL, and prevents infinite loops in throttle_direct_reclaim() caused by allow_direct_reclaim(pgdat) repeatedly returning false. The kernel hangs due to a task stuck in throttle_direct_reclaim(), caused by a node being incorrectly deemed balanced despite pressure in certain zones, such as ZONE_NORMAL. This issue arises from zone_reclaimable_pages() returning 0 for zones without reclaimable file- backed or anonymous pages, causing zones like ZONE_DMA32 with sufficient free pages to be skipped. The lack of swap or reclaimable pages results in ZONE_DMA32 being ignored during reclaim, masking pressure in other zones. Consequently, pgdat->kswapd_failures remains 0 in balance_pgdat(), preventing fallback mechanisms in allow_direct_reclaim() from being triggered, leading to an infinite loop in throttle_direct_reclaim(). This patch modifies zone_reclaimable_pages() to account for free pages (NR_FREE_PAGES) when no other reclaimable pages exist. This ensures zones with sufficient free pages are not skipped, enabling proper balancing and reclaim behavior. [[email protected]: coding-style cleanups] Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Fixes: 5a1c84b ("mm: remove reclaim and compaction retry approximations") Signed-off-by: Seiji Nishikawa <[email protected]> Cc: Mel Gorman <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Chase reports that their tester complaints about a locking context mismatch: ============================= [ BUG: Invalid wait context ] 6.13.0-rc1-gf137f14b7ccb-dirty torvalds#9 Not tainted ----------------------------- syz.1.25198/182604 is trying to lock: ffff88805e66a358 (&ctx->timeout_lock){-.-.}-{3:3}, at: spin_lock_irq include/linux/spinlock.h:376 [inline] ffff88805e66a358 (&ctx->timeout_lock){-.-.}-{3:3}, at: io_match_task_safe io_uring/io_uring.c:218 [inline] ffff88805e66a358 (&ctx->timeout_lock){-.-.}-{3:3}, at: io_match_task_safe+0x187/0x250 io_uring/io_uring.c:204 other info that might help us debug this: context-{5:5} 1 lock held by syz.1.25198/182604: #0: ffff88802b7d48c0 (&acct->lock){+.+.}-{2:2}, at: io_acct_cancel_pending_work+0x2d/0x6b0 io_uring/io-wq.c:1049 stack backtrace: CPU: 0 UID: 0 PID: 182604 Comm: syz.1.25198 Not tainted 6.13.0-rc1-gf137f14b7ccb-dirty torvalds#9 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x82/0xd0 lib/dump_stack.c:120 print_lock_invalid_wait_context kernel/locking/lockdep.c:4826 [inline] check_wait_context kernel/locking/lockdep.c:4898 [inline] __lock_acquire+0x883/0x3c80 kernel/locking/lockdep.c:5176 lock_acquire.part.0+0x11b/0x370 kernel/locking/lockdep.c:5849 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0x36/0x50 kernel/locking/spinlock.c:170 spin_lock_irq include/linux/spinlock.h:376 [inline] io_match_task_safe io_uring/io_uring.c:218 [inline] io_match_task_safe+0x187/0x250 io_uring/io_uring.c:204 io_acct_cancel_pending_work+0xb8/0x6b0 io_uring/io-wq.c:1052 io_wq_cancel_pending_work io_uring/io-wq.c:1074 [inline] io_wq_cancel_cb+0xb0/0x390 io_uring/io-wq.c:1112 io_uring_try_cancel_requests+0x15e/0xd70 io_uring/io_uring.c:3062 io_uring_cancel_generic+0x6ec/0x8c0 io_uring/io_uring.c:3140 io_uring_files_cancel include/linux/io_uring.h:20 [inline] do_exit+0x494/0x27a0 kernel/exit.c:894 do_group_exit+0xb3/0x250 kernel/exit.c:1087 get_signal+0x1d77/0x1ef0 kernel/signal.c:3017 arch_do_signal_or_restart+0x79/0x5b0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xd8/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f which is because io_uring has ctx->timeout_lock nesting inside the io-wq acct lock, the latter of which is used from inside the scheduler and hence is a raw spinlock, while the former is a "normal" spinlock and can hence be sleeping on PREEMPT_RT. Change ctx->timeout_lock to be a raw spinlock to solve this nesting dependency on PREEMPT_RT=y. Reported-by: chase xd <[email protected]> Signed-off-by: Jens Axboe <[email protected]>

…le_direct_reclaim() The task sometimes continues looping in throttle_direct_reclaim() because allow_direct_reclaim(pgdat) keeps returning false. #0 [ffff80002cb6f8d0] __switch_to at ffff8000080095ac #1 [ffff80002cb6f900] __schedule at ffff800008abbd1c #2 [ffff80002cb6f990] schedule at ffff800008abc50c #3 [ffff80002cb6f9b0] throttle_direct_reclaim at ffff800008273550 #4 [ffff80002cb6fa20] try_to_free_pages at ffff800008277b68 #5 [ffff80002cb6fae0] __alloc_pages_nodemask at ffff8000082c4660 torvalds#6 [ffff80002cb6fc50] alloc_pages_vma at ffff8000082e4a98 torvalds#7 [ffff80002cb6fca0] do_anonymous_page at ffff80000829f5a8 torvalds#8 [ffff80002cb6fce0] __handle_mm_fault at ffff8000082a5974 torvalds#9 [ffff80002cb6fd90] handle_mm_fault at ffff8000082a5bd4 At this point, the pgdat contains the following two zones: NODE: 4 ZONE: 0 ADDR: ffff00817fffe540 NAME: "DMA32" SIZE: 20480 MIN/LOW/HIGH: 11/28/45 VM_STAT: NR_FREE_PAGES: 359 NR_ZONE_INACTIVE_ANON: 18813 NR_ZONE_ACTIVE_ANON: 0 NR_ZONE_INACTIVE_FILE: 50 NR_ZONE_ACTIVE_FILE: 0 NR_ZONE_UNEVICTABLE: 0 NR_ZONE_WRITE_PENDING: 0 NR_MLOCK: 0 NR_BOUNCE: 0 NR_ZSPAGES: 0 NR_FREE_CMA_PAGES: 0 NODE: 4 ZONE: 1 ADDR: ffff00817fffec00 NAME: "Normal" SIZE: 8454144 PRESENT: 98304 MIN/LOW/HIGH: 68/166/264 VM_STAT: NR_FREE_PAGES: 146 NR_ZONE_INACTIVE_ANON: 94668 NR_ZONE_ACTIVE_ANON: 3 NR_ZONE_INACTIVE_FILE: 735 NR_ZONE_ACTIVE_FILE: 78 NR_ZONE_UNEVICTABLE: 0 NR_ZONE_WRITE_PENDING: 0 NR_MLOCK: 0 NR_BOUNCE: 0 NR_ZSPAGES: 0 NR_FREE_CMA_PAGES: 0 In allow_direct_reclaim(), while processing ZONE_DMA32, the sum of inactive/active file-backed pages calculated in zone_reclaimable_pages() based on the result of zone_page_state_snapshot() is zero. Additionally, since this system lacks swap, the calculation of inactive/ active anonymous pages is skipped. crash> p nr_swap_pages nr_swap_pages = $1937 = { counter = 0 } As a result, ZONE_DMA32 is deemed unreclaimable and skipped, moving on to the processing of the next zone, ZONE_NORMAL, despite ZONE_DMA32 having free pages significantly exceeding the high watermark. The problem is that the pgdat->kswapd_failures hasn't been incremented. crash> px ((struct pglist_data *) 0xffff00817fffe540)->kswapd_failures $1935 = 0x0 This is because the node deemed balanced. The node balancing logic in balance_pgdat() evaluates all zones collectively. If one or more zones (e.g., ZONE_DMA32) have enough free pages to meet their watermarks, the entire node is deemed balanced. This causes balance_pgdat() to exit early before incrementing the kswapd_failures, as it considers the overall memory state acceptable, even though some zones (like ZONE_NORMAL) remain under significant pressure. The patch ensures that zone_reclaimable_pages() includes free pages (NR_FREE_PAGES) in its calculation when no other reclaimable pages are available (e.g., file-backed or anonymous pages). This change prevents zones like ZONE_DMA32, which have sufficient free pages, from being mistakenly deemed unreclaimable. By doing so, the patch ensures proper node balancing, avoids masking pressure on other zones like ZONE_NORMAL, and prevents infinite loops in throttle_direct_reclaim() caused by allow_direct_reclaim(pgdat) repeatedly returning false. The kernel hangs due to a task stuck in throttle_direct_reclaim(), caused by a node being incorrectly deemed balanced despite pressure in certain zones, such as ZONE_NORMAL. This issue arises from zone_reclaimable_pages() returning 0 for zones without reclaimable file- backed or anonymous pages, causing zones like ZONE_DMA32 with sufficient free pages to be skipped. The lack of swap or reclaimable pages results in ZONE_DMA32 being ignored during reclaim, masking pressure in other zones. Consequently, pgdat->kswapd_failures remains 0 in balance_pgdat(), preventing fallback mechanisms in allow_direct_reclaim() from being triggered, leading to an infinite loop in throttle_direct_reclaim(). This patch modifies zone_reclaimable_pages() to account for free pages (NR_FREE_PAGES) when no other reclaimable pages exist. This ensures zones with sufficient free pages are not skipped, enabling proper balancing and reclaim behavior. [[email protected]: coding-style cleanups] Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Fixes: 5a1c84b ("mm: remove reclaim and compaction retry approximations") Signed-off-by: Seiji Nishikawa <[email protected]> Cc: Mel Gorman <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

This fixes the following hard lockup in isolate_lru_folios() during memory reclaim. If the LRU mostly contains ineligible folios this may trigger watchdog. watchdog: Watchdog detected hard LOCKUP on cpu 173 RIP: 0010:native_queued_spin_lock_slowpath+0x255/0x2a0 Call Trace: _raw_spin_lock_irqsave+0x31/0x40 folio_lruvec_lock_irqsave+0x5f/0x90 folio_batch_move_lru+0x91/0x150 lru_add_drain_per_cpu+0x1c/0x40 process_one_work+0x17d/0x350 worker_thread+0x27b/0x3a0 kthread+0xe8/0x120 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1b/0x30 lruvec->lru_lock owner： PID: 2865 TASK: ffff888139214d40 CPU: 40 COMMAND: "kswapd0" #0 [fffffe0000945e60] crash_nmi_callback at ffffffffa567a555 #1 [fffffe0000945e68] nmi_handle at ffffffffa563b171 #2 [fffffe0000945eb0] default_do_nmi at ffffffffa6575920 #3 [fffffe0000945ed0] exc_nmi at ffffffffa6575af4 #4 [fffffe0000945ef0] end_repeat_nmi at ffffffffa6601dde [exception RIP: isolate_lru_folios+403] RIP: ffffffffa597df53 RSP: ffffc90006fb7c28 RFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffc90006fb7c60 RCX: ffffea04a2196f88 RDX: ffffc90006fb7c60 RSI: ffffc90006fb7c60 RDI: ffffea04a2197048 RBP: ffff88812cbd3010 R8: ffffea04a2197008 R9: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea04a2197008 R13: ffffea04a2197048 R14: ffffc90006fb7de8 R15: 0000000003e3e937 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 <NMI exception stack> #5 [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 torvalds#6 [ffffc90006fb7cf8] shrink_active_list at ffffffffa597f788 torvalds#7 [ffffc90006fb7da8] balance_pgdat at ffffffffa5986db0 torvalds#8 [ffffc90006fb7ec0] kswapd at ffffffffa5987354 torvalds#9 [ffffc90006fb7ef8] kthread at ffffffffa5748238 crash> Scenario: User processe are requesting a large amount of memory and keep page active. Then a module continuously requests memory from ZONE_DMA32 area. Memory reclaim will be triggered due to ZONE_DMA32 watermark alarm reached. However pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. Reproduce: Terminal 1: Construct to continuously increase pages active(anon). mkdir /tmp/memory mount -t tmpfs -o size=1024000M tmpfs /tmp/memory dd if=/dev/zero of=/tmp/memory/block bs=4M tail /tmp/memory/block Terminal 2: vmstat -a 1 active will increase. procs ---memory--- ---swap-- ---io---- -system-- ---cpu--- ... r b swpd free inact active si so bi bo 1 0 0 1445623076 45898836 83646008 0 0 0 1 0 0 1445623076 43450228 86094616 0 0 0 1 0 0 1445623076 41003480 88541364 0 0 0 1 0 0 1445623076 38557088 90987756 0 0 0 1 0 0 1445623076 36109688 93435156 0 0 0 1 0 0 1445619552 33663256 95881632 0 0 0 1 0 0 1445619804 31217140 98327792 0 0 0 1 0 0 1445619804 28769988 100774944 0 0 0 1 0 0 1445619804 26322348 103222584 0 0 0 1 0 0 1445619804 23875592 105669340 0 0 0 cat /proc/meminfo | head Active(anon) increase. MemTotal: 1579941036 kB MemFree: 1445618500 kB MemAvailable: 1453013224 kB Buffers: 6516 kB Cached: 128653956 kB SwapCached: 0 kB Active: 118110812 kB Inactive: 11436620 kB Active(anon): 115345744 kB Inactive(anon): 945292 kB When the Active(anon) is 115345744 kB, insmod module triggers the ZONE_DMA32 watermark. perf record -e vmscan:mm_vmscan_lru_isolate -aR perf script isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=2 nr_skipped=2 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=29 nr_skipped=29 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon See nr_scanned=28835844. 28835844 * 4k = 115343376KB approximately equal to 115345744 kB. If increase Active(anon) to 1000G then insmod module triggers the ZONE_DMA32 watermark. hard lockup will occur. In my device nr_scanned = 0000000003e3e937 when hard lockup. Convert to memory size 0x0000000003e3e937 * 4KB = 261072092 KB. [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 ffffc90006fb7c30: 0000000000000020 0000000000000000 ffffc90006fb7c40: ffffc90006fb7d40 ffff88812cbd3000 ffffc90006fb7c50: ffffc90006fb7d30 0000000106fb7de8 ffffc90006fb7c60: ffffea04a2197008 ffffea0006ed4a48 ffffc90006fb7c70: 0000000000000000 0000000000000000 ffffc90006fb7c80: 0000000000000000 0000000000000000 ffffc90006fb7c90: 0000000000000000 0000000000000000 ffffc90006fb7ca0: 0000000000000000 0000000003e3e937 ffffc90006fb7cb0: 0000000000000000 0000000000000000 ffffc90006fb7cc0: 8d7c0b56b7874b00 ffff88812cbd3000 About the Fixes: Why did it take eight years to be discovered? The problem requires the following conditions to occur: 1. The device memory should be large enough. 2. Pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. 3. The memory in ZONE_DMA32 needs to reach the watermark. If the memory is not large enough, or if the usage design of ZONE_DMA32 area memory is reasonable, this problem is difficult to detect. notes: The problem is most likely to occur in ZONE_DMA32 and ZONE_NORMAL, but other suitable scenarios may also trigger the problem. Link: https://lkml.kernel.org/r/[email protected] Fixes: b2e1875 ("mm, vmscan: begin reclaiming pages on a per-node basis") Signed-off-by: liuye <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Yang Shi <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Removed extra 'an' in ext4 docs.

81a5f50

smartinez87 closed this Sep 6, 2011

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Removed extra 'an' in ext4 docs. #9

Removed extra 'an' in ext4 docs. #9

smartinez87 commented Sep 5, 2011

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VM2 commented Sep 7, 2011

Removed extra 'an' in ext4 docs. #9

Removed extra 'an' in ext4 docs. #9

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smartinez87 commented Sep 5, 2011

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