UNTESTED AIC driver cleanup/reorg #2

pipcet · 2021-08-11T09:58:35Z

This:

fixes the disable_irq bug @svenpeter42 found
splits FIQ handling into its own file
splits IPI->vIPI translation/funneling into its own file
allows multi-CPU affinities
handles IRQ events one event at a time rather than in a loop

TODO:

FIQ IPIs. We should be prepared for them now, since it seems we still don't have enough IPIs...
skip the vGIC code in the common case to speed up IRQ handling
smarter strategy to decide whether to handle a single event or to loop over IRQ events
handle FIQs one event at a time (using if-then-else) rather than handling all pending FIQs
lots of testing

In a memory pressure situation, I'm seeing the lockdep WARNING below. Actually, this is similar to a known false positive which is already addressed by commit 6dcde60 ("xfs: more lockdep whackamole with kmem_alloc*"). This warning still persists because it's not from kmalloc() itself but from an allocation for kmemleak object. While kmalloc() itself suppress the warning with __GFP_NOLOCKDEP, gfp_kmemleak_mask() is dropping the flag for the kmemleak's allocation. Allow __GFP_NOLOCKDEP to be passed to kmemleak's allocation, so that the warning for it is also suppressed. ====================================================== WARNING: possible circular locking dependency detected 5.14.0-rc7-BTRFS-ZNS+ torvalds#37 Not tainted ------------------------------------------------------ kswapd0/288 is trying to acquire lock: ffff88825ab45df0 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_ilock+0x8a/0x250 but task is already holding lock: ffffffff848cc1e0 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}-{0:0}: fs_reclaim_acquire+0x112/0x160 kmem_cache_alloc+0x48/0x400 create_object.isra.0+0x42/0xb10 kmemleak_alloc+0x48/0x80 __kmalloc+0x228/0x440 kmem_alloc+0xd3/0x2b0 kmem_alloc_large+0x5a/0x1c0 xfs_attr_copy_value+0x112/0x190 xfs_attr_shortform_getvalue+0x1fc/0x300 xfs_attr_get_ilocked+0x125/0x170 xfs_attr_get+0x329/0x450 xfs_get_acl+0x18d/0x430 get_acl.part.0+0xb6/0x1e0 posix_acl_xattr_get+0x13a/0x230 vfs_getxattr+0x21d/0x270 getxattr+0x126/0x310 __x64_sys_fgetxattr+0x1a6/0x2a0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #0 (&xfs_nondir_ilock_class){++++}-{3:3}: __lock_acquire+0x2c0f/0x5a00 lock_acquire+0x1a1/0x4b0 down_read_nested+0x50/0x90 xfs_ilock+0x8a/0x250 xfs_can_free_eofblocks+0x34f/0x570 xfs_inactive+0x411/0x520 xfs_fs_destroy_inode+0x2c8/0x710 destroy_inode+0xc5/0x1a0 evict+0x444/0x620 dispose_list+0xfe/0x1c0 prune_icache_sb+0xdc/0x160 super_cache_scan+0x31e/0x510 do_shrink_slab+0x337/0x8e0 shrink_slab+0x362/0x5c0 shrink_node+0x7a7/0x1a40 balance_pgdat+0x64e/0xfe0 kswapd+0x590/0xa80 kthread+0x38c/0x460 ret_from_fork+0x22/0x30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&xfs_nondir_ilock_class); lock(fs_reclaim); lock(&xfs_nondir_ilock_class); *** DEADLOCK *** 3 locks held by kswapd0/288: #0: ffffffff848cc1e0 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 #1: ffffffff848a08d8 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x269/0x5c0 #2: ffff8881a7a820e8 (&type->s_umount_key#60){++++}-{3:3}, at: super_cache_scan+0x5a/0x510 Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Naohiro Aota <[email protected]> Acked-by: Catalin Marinas <[email protected]> Cc: "Darrick J . Wong" <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

pasid_mutex and dev->iommu->param->lock are held while unbinding mm is flushing IO page fault workqueue and waiting for all page fault works to finish. But an in-flight page fault work also need to hold the two locks while unbinding mm are holding them and waiting for the work to finish. This may cause an ABBA deadlock issue as shown below: idxd 0000:00:0a.0: unbind PASID 2 ====================================================== WARNING: possible circular locking dependency detected 5.14.0-rc7+ torvalds#549 Not tainted [ 186.615245] ---------- dsa_test/898 is trying to acquire lock: ffff888100d854e8 (&param->lock){+.+.}-{3:3}, at: iopf_queue_flush_dev+0x29/0x60 but task is already holding lock: ffffffff82b2f7c8 (pasid_mutex){+.+.}-{3:3}, at: intel_svm_unbind+0x34/0x1e0 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (pasid_mutex){+.+.}-{3:3}: __mutex_lock+0x75/0x730 mutex_lock_nested+0x1b/0x20 intel_svm_page_response+0x8e/0x260 iommu_page_response+0x122/0x200 iopf_handle_group+0x1c2/0x240 process_one_work+0x2a5/0x5a0 worker_thread+0x55/0x400 kthread+0x13b/0x160 ret_from_fork+0x22/0x30 -> #1 (&param->fault_param->lock){+.+.}-{3:3}: __mutex_lock+0x75/0x730 mutex_lock_nested+0x1b/0x20 iommu_report_device_fault+0xc2/0x170 prq_event_thread+0x28a/0x580 irq_thread_fn+0x28/0x60 irq_thread+0xcf/0x180 kthread+0x13b/0x160 ret_from_fork+0x22/0x30 -> #0 (&param->lock){+.+.}-{3:3}: __lock_acquire+0x1134/0x1d60 lock_acquire+0xc6/0x2e0 __mutex_lock+0x75/0x730 mutex_lock_nested+0x1b/0x20 iopf_queue_flush_dev+0x29/0x60 intel_svm_drain_prq+0x127/0x210 intel_svm_unbind+0xc5/0x1e0 iommu_sva_unbind_device+0x62/0x80 idxd_cdev_release+0x15a/0x200 [idxd] __fput+0x9c/0x250 ____fput+0xe/0x10 task_work_run+0x64/0xa0 exit_to_user_mode_prepare+0x227/0x230 syscall_exit_to_user_mode+0x2c/0x60 do_syscall_64+0x48/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Chain exists of: &param->lock --> &param->fault_param->lock --> pasid_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(pasid_mutex); lock(&param->fault_param->lock); lock(pasid_mutex); lock(&param->lock); *** DEADLOCK *** 2 locks held by dsa_test/898: #0: ffff888100cc1cc0 (&group->mutex){+.+.}-{3:3}, at: iommu_sva_unbind_device+0x53/0x80 #1: ffffffff82b2f7c8 (pasid_mutex){+.+.}-{3:3}, at: intel_svm_unbind+0x34/0x1e0 stack backtrace: CPU: 2 PID: 898 Comm: dsa_test Not tainted 5.14.0-rc7+ torvalds#549 Hardware name: Intel Corporation Kabylake Client platform/KBL S DDR4 UD IMM CRB, BIOS KBLSE2R1.R00.X050.P01.1608011715 08/01/2016 Call Trace: dump_stack_lvl+0x5b/0x74 dump_stack+0x10/0x12 print_circular_bug.cold+0x13d/0x142 check_noncircular+0xf1/0x110 __lock_acquire+0x1134/0x1d60 lock_acquire+0xc6/0x2e0 ? iopf_queue_flush_dev+0x29/0x60 ? pci_mmcfg_read+0xde/0x240 __mutex_lock+0x75/0x730 ? iopf_queue_flush_dev+0x29/0x60 ? pci_mmcfg_read+0xfd/0x240 ? iopf_queue_flush_dev+0x29/0x60 mutex_lock_nested+0x1b/0x20 iopf_queue_flush_dev+0x29/0x60 intel_svm_drain_prq+0x127/0x210 ? intel_pasid_tear_down_entry+0x22e/0x240 intel_svm_unbind+0xc5/0x1e0 iommu_sva_unbind_device+0x62/0x80 idxd_cdev_release+0x15a/0x200 pasid_mutex protects pasid and svm data mapping data. It's unnecessary to hold pasid_mutex while flushing the workqueue. To fix the deadlock issue, unlock pasid_pasid during flushing the workqueue to allow the works to be handled. Fixes: d5b9e4b ("iommu/vt-d: Report prq to io-pgfault framework") Reported-and-tested-by: Dave Jiang <[email protected]> Signed-off-by: Fenghua Yu <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Lu Baolu <[email protected]> Link: https://lore.kernel.org/r/[email protected] [joro: Removed timing information from kernel log messages] Signed-off-by: Joerg Roedel <[email protected]>

#2

when turning off a connection, lockdep complains with the following warning (a modprobe has been done but the same happens with a disconnection from NetworkManager, it's enough to trigger a cfg80211_disconnect call): [ 682.855867] ====================================================== [ 682.855877] WARNING: possible circular locking dependency detected [ 682.855887] 5.14.0-rc6+ torvalds#16 Tainted: G C OE [ 682.855898] ------------------------------------------------------ [ 682.855906] modprobe/1770 is trying to acquire lock: [ 682.855916] ffffb6d000332b00 (&pxmitpriv->lock){+.-.}-{2:2}, at: rtw_free_stainfo+0x52/0x4a0 [r8723bs] [ 682.856073] but task is already holding lock: [ 682.856081] ffffb6d0003336a8 (&pstapriv->sta_hash_lock){+.-.}-{2:2}, at: rtw_free_assoc_resources+0x48/0x110 [r8723bs] [ 682.856207] which lock already depends on the new lock. [ 682.856215] the existing dependency chain (in reverse order) is: [ 682.856223] -> #1 (&pstapriv->sta_hash_lock){+.-.}-{2:2}: [ 682.856247] _raw_spin_lock_bh+0x34/0x40 [ 682.856265] rtw_get_stainfo+0x9a/0x110 [r8723bs] [ 682.856389] rtw_xmit_classifier+0x27/0x130 [r8723bs] [ 682.856515] rtw_xmitframe_enqueue+0xa/0x20 [r8723bs] [ 682.856642] rtl8723bs_hal_xmit+0x3b/0xb0 [r8723bs] [ 682.856752] rtw_xmit+0x4ef/0x890 [r8723bs] [ 682.856879] _rtw_xmit_entry+0xba/0x350 [r8723bs] [ 682.856981] dev_hard_start_xmit+0xee/0x320 [ 682.856999] sch_direct_xmit+0x8c/0x330 [ 682.857014] __dev_queue_xmit+0xba5/0xf00 [ 682.857030] packet_sendmsg+0x981/0x1b80 [ 682.857047] sock_sendmsg+0x5b/0x60 [ 682.857060] __sys_sendto+0xf1/0x160 [ 682.857073] __x64_sys_sendto+0x24/0x30 [ 682.857087] do_syscall_64+0x3a/0x80 [ 682.857102] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 682.857117] -> #0 (&pxmitpriv->lock){+.-.}-{2:2}: [ 682.857142] __lock_acquire+0xfd9/0x1b50 [ 682.857158] lock_acquire+0xb4/0x2c0 [ 682.857172] _raw_spin_lock_bh+0x34/0x40 [ 682.857185] rtw_free_stainfo+0x52/0x4a0 [r8723bs] [ 682.857308] rtw_free_assoc_resources+0x53/0x110 [r8723bs] [ 682.857415] cfg80211_rtw_disconnect+0x4b/0x70 [r8723bs] [ 682.857522] cfg80211_disconnect+0x12e/0x2f0 [cfg80211] [ 682.857759] cfg80211_leave+0x2b/0x40 [cfg80211] [ 682.857961] cfg80211_netdev_notifier_call+0xa9/0x560 [cfg80211] [ 682.858163] raw_notifier_call_chain+0x41/0x50 [ 682.858180] __dev_close_many+0x62/0x100 [ 682.858195] dev_close_many+0x7d/0x120 [ 682.858209] unregister_netdevice_many+0x416/0x680 [ 682.858225] unregister_netdevice_queue+0xab/0xf0 [ 682.858240] unregister_netdev+0x18/0x20 [ 682.858255] rtw_unregister_netdevs+0x28/0x40 [r8723bs] [ 682.858360] rtw_dev_remove+0x24/0xd0 [r8723bs] [ 682.858463] sdio_bus_remove+0x31/0xd0 [mmc_core] [ 682.858532] device_release_driver_internal+0xf7/0x1d0 [ 682.858550] driver_detach+0x47/0x90 [ 682.858564] bus_remove_driver+0x77/0xd0 [ 682.858579] rtw_drv_halt+0xc/0x678 [r8723bs] [ 682.858685] __x64_sys_delete_module+0x13f/0x250 [ 682.858699] do_syscall_64+0x3a/0x80 [ 682.858715] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 682.858729] other info that might help us debug this: [ 682.858737] Possible unsafe locking scenario: [ 682.858744] CPU0 CPU1 [ 682.858751] ---- ---- [ 682.858758] lock(&pstapriv->sta_hash_lock); [ 682.858772] lock(&pxmitpriv->lock); [ 682.858786] lock(&pstapriv->sta_hash_lock); [ 682.858799] lock(&pxmitpriv->lock); [ 682.858812] *** DEADLOCK *** [ 682.858820] 5 locks held by modprobe/1770: [ 682.858831] #0: ffff8d870697d980 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0x1a/0x1d0 [ 682.858869] #1: ffffffffbdbbf1c8 (rtnl_mutex){+.+.}-{3:3}, at: unregister_netdev+0xe/0x20 [ 682.858906] #2: ffff8d87054ee5e8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: cfg80211_netdev_notifier_call+0x9e/0x560 [cfg80211] [ 682.859131] #3: ffff8d870f2bc8f0 (&wdev->mtx){+.+.}-{3:3}, at: cfg80211_leave+0x20/0x40 [cfg80211] [ 682.859354] #4: ffffb6d0003336a8 (&pstapriv->sta_hash_lock){+.-.}-{2:2}, at: rtw_free_assoc_resources+0x48/0x110 [r8723bs] [ 682.859482] stack backtrace: [ 682.859491] CPU: 1 PID: 1770 Comm: modprobe Tainted: G C OE 5.14.0-rc6+ torvalds#16 [ 682.859507] Hardware name: LENOVO 80NR/Madrid, BIOS DACN25WW 08/20/2015 [ 682.859517] Call Trace: [ 682.859531] dump_stack_lvl+0x56/0x6f [ 682.859551] check_noncircular+0xdb/0xf0 [ 682.859579] __lock_acquire+0xfd9/0x1b50 [ 682.859606] lock_acquire+0xb4/0x2c0 [ 682.859623] ? rtw_free_stainfo+0x52/0x4a0 [r8723bs] [ 682.859752] ? mark_held_locks+0x48/0x70 [ 682.859769] ? rtw_free_stainfo+0x4a/0x4a0 [r8723bs] [ 682.859898] _raw_spin_lock_bh+0x34/0x40 [ 682.859914] ? rtw_free_stainfo+0x52/0x4a0 [r8723bs] [ 682.860039] rtw_free_stainfo+0x52/0x4a0 [r8723bs] [ 682.860171] rtw_free_assoc_resources+0x53/0x110 [r8723bs] [ 682.860286] cfg80211_rtw_disconnect+0x4b/0x70 [r8723bs] [ 682.860397] cfg80211_disconnect+0x12e/0x2f0 [cfg80211] [ 682.860629] cfg80211_leave+0x2b/0x40 [cfg80211] [ 682.860836] cfg80211_netdev_notifier_call+0xa9/0x560 [cfg80211] [ 682.861048] ? __lock_acquire+0x4dc/0x1b50 [ 682.861070] ? lock_is_held_type+0xa8/0x110 [ 682.861089] ? lock_is_held_type+0xa8/0x110 [ 682.861104] ? find_held_lock+0x2d/0x90 [ 682.861120] ? packet_notifier+0x173/0x300 [ 682.861141] ? lock_release+0xb3/0x250 [ 682.861160] ? packet_notifier+0x192/0x300 [ 682.861184] raw_notifier_call_chain+0x41/0x50 [ 682.861205] __dev_close_many+0x62/0x100 [ 682.861224] dev_close_many+0x7d/0x120 [ 682.861245] unregister_netdevice_many+0x416/0x680 [ 682.861264] ? find_held_lock+0x2d/0x90 [ 682.861284] unregister_netdevice_queue+0xab/0xf0 [ 682.861306] unregister_netdev+0x18/0x20 [ 682.861325] rtw_unregister_netdevs+0x28/0x40 [r8723bs] [ 682.861434] rtw_dev_remove+0x24/0xd0 [r8723bs] [ 682.861542] sdio_bus_remove+0x31/0xd0 [mmc_core] [ 682.861615] device_release_driver_internal+0xf7/0x1d0 [ 682.861637] driver_detach+0x47/0x90 [ 682.861656] bus_remove_driver+0x77/0xd0 [ 682.861674] rtw_drv_halt+0xc/0x678 [r8723bs] [ 682.861782] __x64_sys_delete_module+0x13f/0x250 [ 682.861801] ? lockdep_hardirqs_on_prepare+0xf3/0x170 [ 682.861817] ? syscall_enter_from_user_mode+0x20/0x70 [ 682.861836] do_syscall_64+0x3a/0x80 [ 682.861855] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 682.861873] RIP: 0033:0x7f6dbe85400b [ 682.861890] Code: 73 01 c3 48 8b 0d 6d 1e 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 3d 1e 0c 00 f7 d8 64 89 01 48 [ 682.861906] RSP: 002b:00007ffe7a82f538 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 [ 682.861923] RAX: ffffffffffffffda RBX: 000055a64693bd20 RCX: 00007f6dbe85400b [ 682.861935] RDX: 0000000000000000 RSI: 0000000000000800 RDI: 000055a64693bd88 [ 682.861946] RBP: 000055a64693bd20 R08: 0000000000000000 R09: 0000000000000000 [ 682.861957] R10: 00007f6dbe8c7ac0 R11: 0000000000000206 R12: 000055a64693bd88 [ 682.861967] R13: 0000000000000000 R14: 000055a64693bd88 R15: 00007ffe7a831848 This happens because when we enqueue a frame for transmission we do it under xmit_priv lock, then calling rtw_get_stainfo (needed for enqueuing) takes sta_hash_lock and this leads to the following lock dependency: xmit_priv->lock -> sta_hash_lock Turning off a connection will bring to call rtw_free_assoc_resources which will set up the inverse dependency: sta_hash_lock -> xmit_priv_lock This could lead to a deadlock as lockdep complains. Fix it by removing the xmit_priv->lock around rtw_xmitframe_enqueue call inside rtl8723bs_hal_xmit and put it in a smaller critical section inside rtw_xmit_classifier, the only place where xmit_priv data are actually accessed. Replace spin_{lock,unlock}_bh(pxmitpriv->lock) in other tx paths leading to rtw_xmitframe_enqueue call with spin_{lock,unlock}_bh(psta->sleep_q.lock) - it's not clear why accessing a sleep_q was protected by a spinlock on xmitpriv->lock. This way is avoided the same faulty lock nesting order. CC: Larry Finger <[email protected]> Tested-on: Lenovo Ideapad MiiX 300-10IBY Signed-off-by: Fabio Aiuto <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>

We got the following lockdep splat while running xfstests (specifically btrfs/003 and btrfs/020 in a row) with the new rc. This was uncovered by 87579e9 ("loop: use worker per cgroup instead of kworker") which converted loop to using workqueues, which comes with lockdep annotations that don't exist with kworkers. The lockdep splat is as follows ====================================================== WARNING: possible circular locking dependency detected 5.14.0-rc2-custom+ torvalds#34 Not tainted ------------------------------------------------------ losetup/156417 is trying to acquire lock: ffff9c7645b02d38 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x84/0x600 but task is already holding lock: ffff9c7647395468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x650 [loop] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&lo->lo_mutex){+.+.}-{3:3}: __mutex_lock+0xba/0x7c0 lo_open+0x28/0x60 [loop] blkdev_get_whole+0x28/0xf0 blkdev_get_by_dev.part.0+0x168/0x3c0 blkdev_open+0xd2/0xe0 do_dentry_open+0x163/0x3a0 path_openat+0x74d/0xa40 do_filp_open+0x9c/0x140 do_sys_openat2+0xb1/0x170 __x64_sys_openat+0x54/0x90 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #4 (&disk->open_mutex){+.+.}-{3:3}: __mutex_lock+0xba/0x7c0 blkdev_get_by_dev.part.0+0xd1/0x3c0 blkdev_get_by_path+0xc0/0xd0 btrfs_scan_one_device+0x52/0x1f0 [btrfs] btrfs_control_ioctl+0xac/0x170 [btrfs] __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #3 (uuid_mutex){+.+.}-{3:3}: __mutex_lock+0xba/0x7c0 btrfs_rm_device+0x48/0x6a0 [btrfs] btrfs_ioctl+0x2d1c/0x3110 [btrfs] __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #2 (sb_writers#11){.+.+}-{0:0}: lo_write_bvec+0x112/0x290 [loop] loop_process_work+0x25f/0xcb0 [loop] process_one_work+0x28f/0x5d0 worker_thread+0x55/0x3c0 kthread+0x140/0x170 ret_from_fork+0x22/0x30 -> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}: process_one_work+0x266/0x5d0 worker_thread+0x55/0x3c0 kthread+0x140/0x170 ret_from_fork+0x22/0x30 -> #0 ((wq_completion)loop0){+.+.}-{0:0}: __lock_acquire+0x1130/0x1dc0 lock_acquire+0xf5/0x320 flush_workqueue+0xae/0x600 drain_workqueue+0xa0/0x110 destroy_workqueue+0x36/0x250 __loop_clr_fd+0x9a/0x650 [loop] lo_ioctl+0x29d/0x780 [loop] block_ioctl+0x3f/0x50 __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Chain exists of: (wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&lo->lo_mutex); lock(&disk->open_mutex); lock(&lo->lo_mutex); lock((wq_completion)loop0); *** DEADLOCK *** 1 lock held by losetup/156417: #0: ffff9c7647395468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x650 [loop] stack backtrace: CPU: 8 PID: 156417 Comm: losetup Not tainted 5.14.0-rc2-custom+ torvalds#34 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: dump_stack_lvl+0x57/0x72 check_noncircular+0x10a/0x120 __lock_acquire+0x1130/0x1dc0 lock_acquire+0xf5/0x320 ? flush_workqueue+0x84/0x600 flush_workqueue+0xae/0x600 ? flush_workqueue+0x84/0x600 drain_workqueue+0xa0/0x110 destroy_workqueue+0x36/0x250 __loop_clr_fd+0x9a/0x650 [loop] lo_ioctl+0x29d/0x780 [loop] ? __lock_acquire+0x3a0/0x1dc0 ? update_dl_rq_load_avg+0x152/0x360 ? lock_is_held_type+0xa5/0x120 ? find_held_lock.constprop.0+0x2b/0x80 block_ioctl+0x3f/0x50 __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f645884de6b Usually the uuid_mutex exists to protect the fs_devices that map together all of the devices that match a specific uuid. In rm_device we're messing with the uuid of a device, so it makes sense to protect that here. However in doing that it pulls in a whole host of lockdep dependencies, as we call mnt_may_write() on the sb before we grab the uuid_mutex, thus we end up with the dependency chain under the uuid_mutex being added under the normal sb write dependency chain, which causes problems with loop devices. We don't need the uuid mutex here however. If we call btrfs_scan_one_device() before we scratch the super block we will find the fs_devices and not find the device itself and return EBUSY because the fs_devices is open. If we call it after the scratch happens it will not appear to be a valid btrfs file system. We do not need to worry about other fs_devices modifying operations here because we're protected by the exclusive operations locking. So drop the uuid_mutex here in order to fix the lockdep splat. Signed-off-by: Josef Bacik <[email protected]> Signed-off-by: David Sterba <[email protected]>

For device removal and replace we call btrfs_find_device_by_devspec, which if we give it a device path and nothing else will call btrfs_find_device_by_path, which opens the block device and reads the super block and then looks up our device based on that. However this is completely unnecessary because we have the path stored in our device on our fsdevices. All we need to do if we're given a path is look through the fs_devices on our file system and use that device if we find it, reading the super block is just silly. This fixes the case where we end up with our sb write "lock" getting the dependency of the block device ->open_mutex, which resulted in the following lockdep splat ====================================================== WARNING: possible circular locking dependency detected 5.14.0-rc2+ torvalds#405 Not tainted ------------------------------------------------------ losetup/11576 is trying to acquire lock: ffff9bbe8cded938 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x67/0x5e0 but task is already holding lock: ffff9bbe88e4fc68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&lo->lo_mutex){+.+.}-{3:3}: __mutex_lock+0x7d/0x750 lo_open+0x28/0x60 [loop] blkdev_get_whole+0x25/0xf0 blkdev_get_by_dev.part.0+0x168/0x3c0 blkdev_open+0xd2/0xe0 do_dentry_open+0x161/0x390 path_openat+0x3cc/0xa20 do_filp_open+0x96/0x120 do_sys_openat2+0x7b/0x130 __x64_sys_openat+0x46/0x70 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #3 (&disk->open_mutex){+.+.}-{3:3}: __mutex_lock+0x7d/0x750 blkdev_get_by_dev.part.0+0x56/0x3c0 blkdev_get_by_path+0x98/0xa0 btrfs_get_bdev_and_sb+0x1b/0xb0 btrfs_find_device_by_devspec+0x12b/0x1c0 btrfs_rm_device+0x127/0x610 btrfs_ioctl+0x2a31/0x2e70 __x64_sys_ioctl+0x80/0xb0 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #2 (sb_writers#12){.+.+}-{0:0}: lo_write_bvec+0xc2/0x240 [loop] loop_process_work+0x238/0xd00 [loop] process_one_work+0x26b/0x560 worker_thread+0x55/0x3c0 kthread+0x140/0x160 ret_from_fork+0x1f/0x30 -> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}: process_one_work+0x245/0x560 worker_thread+0x55/0x3c0 kthread+0x140/0x160 ret_from_fork+0x1f/0x30 -> #0 ((wq_completion)loop0){+.+.}-{0:0}: __lock_acquire+0x10ea/0x1d90 lock_acquire+0xb5/0x2b0 flush_workqueue+0x91/0x5e0 drain_workqueue+0xa0/0x110 destroy_workqueue+0x36/0x250 __loop_clr_fd+0x9a/0x660 [loop] block_ioctl+0x3f/0x50 __x64_sys_ioctl+0x80/0xb0 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Chain exists of: (wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&lo->lo_mutex); lock(&disk->open_mutex); lock(&lo->lo_mutex); lock((wq_completion)loop0); *** DEADLOCK *** 1 lock held by losetup/11576: #0: ffff9bbe88e4fc68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop] stack backtrace: CPU: 0 PID: 11576 Comm: losetup Not tainted 5.14.0-rc2+ torvalds#405 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 Call Trace: dump_stack_lvl+0x57/0x72 check_noncircular+0xcf/0xf0 ? stack_trace_save+0x3b/0x50 __lock_acquire+0x10ea/0x1d90 lock_acquire+0xb5/0x2b0 ? flush_workqueue+0x67/0x5e0 ? lockdep_init_map_type+0x47/0x220 flush_workqueue+0x91/0x5e0 ? flush_workqueue+0x67/0x5e0 ? verify_cpu+0xf0/0x100 drain_workqueue+0xa0/0x110 destroy_workqueue+0x36/0x250 __loop_clr_fd+0x9a/0x660 [loop] ? blkdev_ioctl+0x8d/0x2a0 block_ioctl+0x3f/0x50 __x64_sys_ioctl+0x80/0xb0 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f31b02404cb Signed-off-by: Josef Bacik <[email protected]> Signed-off-by: David Sterba <[email protected]>

#2

As previously noted in commit 66e4f4a ("rtc: cmos: Use spin_lock_irqsave() in cmos_interrupt()"): <4>[ 254.192378] WARNING: inconsistent lock state <4>[ 254.192384] 5.12.0-rc1-CI-CI_DRM_9834+ #1 Not tainted <4>[ 254.192396] -------------------------------- <4>[ 254.192400] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. <4>[ 254.192409] rtcwake/5309 [HC0[0]:SC0[0]:HE1:SE1] takes: <4>[ 254.192429] ffffffff8263c5f8 (rtc_lock){?...}-{2:2}, at: cmos_interrupt+0x18/0x100 <4>[ 254.192481] {IN-HARDIRQ-W} state was registered at: <4>[ 254.192488] lock_acquire+0xd1/0x3d0 <4>[ 254.192504] _raw_spin_lock+0x2a/0x40 <4>[ 254.192519] cmos_interrupt+0x18/0x100 <4>[ 254.192536] rtc_handler+0x1f/0xc0 <4>[ 254.192553] acpi_ev_fixed_event_detect+0x109/0x13c <4>[ 254.192574] acpi_ev_sci_xrupt_handler+0xb/0x28 <4>[ 254.192596] acpi_irq+0x13/0x30 <4>[ 254.192620] __handle_irq_event_percpu+0x43/0x2c0 <4>[ 254.192641] handle_irq_event_percpu+0x2b/0x70 <4>[ 254.192661] handle_irq_event+0x2f/0x50 <4>[ 254.192680] handle_fasteoi_irq+0x9e/0x150 <4>[ 254.192693] __common_interrupt+0x76/0x140 <4>[ 254.192715] common_interrupt+0x96/0xc0 <4>[ 254.192732] asm_common_interrupt+0x1e/0x40 <4>[ 254.192750] _raw_spin_unlock_irqrestore+0x38/0x60 <4>[ 254.192767] resume_irqs+0xba/0xf0 <4>[ 254.192786] dpm_resume_noirq+0x245/0x3d0 <4>[ 254.192811] suspend_devices_and_enter+0x230/0xaa0 <4>[ 254.192835] pm_suspend.cold.8+0x301/0x34a <4>[ 254.192859] state_store+0x7b/0xe0 <4>[ 254.192879] kernfs_fop_write_iter+0x11d/0x1c0 <4>[ 254.192899] new_sync_write+0x11d/0x1b0 <4>[ 254.192916] vfs_write+0x265/0x390 <4>[ 254.192933] ksys_write+0x5a/0xd0 <4>[ 254.192949] do_syscall_64+0x33/0x80 <4>[ 254.192965] entry_SYSCALL_64_after_hwframe+0x44/0xae <4>[ 254.192986] irq event stamp: 43775 <4>[ 254.192994] hardirqs last enabled at (43775): [<ffffffff81c00c42>] asm_sysvec_apic_timer_interrupt+0x12/0x20 <4>[ 254.193023] hardirqs last disabled at (43774): [<ffffffff81aa691a>] sysvec_apic_timer_interrupt+0xa/0xb0 <4>[ 254.193049] softirqs last enabled at (42548): [<ffffffff81e00342>] __do_softirq+0x342/0x48e <4>[ 254.193074] softirqs last disabled at (42543): [<ffffffff810b45fd>] irq_exit_rcu+0xad/0xd0 <4>[ 254.193101] other info that might help us debug this: <4>[ 254.193107] Possible unsafe locking scenario: <4>[ 254.193112] CPU0 <4>[ 254.193117] ---- <4>[ 254.193121] lock(rtc_lock); <4>[ 254.193137] <Interrupt> <4>[ 254.193142] lock(rtc_lock); <4>[ 254.193156] *** DEADLOCK *** <4>[ 254.193161] 6 locks held by rtcwake/5309: <4>[ 254.193174] #0: ffff888104861430 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0x5a/0xd0 <4>[ 254.193232] #1: ffff88810f823288 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0xe7/0x1c0 <4>[ 254.193282] #2: ffff888100cef3c0 (kn->active#285 <7>[ 254.192706] i915 0000:00:02.0: [drm:intel_modeset_setup_hw_state [i915]] [CRTC:51:pipe A] hw state readout: disabled <4>[ 254.193307] ){.+.+}-{0:0}, at: kernfs_fop_write_iter+0xf0/0x1c0 <4>[ 254.193333] #3: ffffffff82649fa8 (system_transition_mutex){+.+.}-{3:3}, at: pm_suspend.cold.8+0xce/0x34a <4>[ 254.193387] #4: ffffffff827a2108 (acpi_scan_lock){+.+.}-{3:3}, at: acpi_suspend_begin+0x47/0x70 <4>[ 254.193433] #5: ffff8881019ea178 (&dev->mutex){....}-{3:3}, at: device_resume+0x68/0x1e0 <4>[ 254.193485] stack backtrace: <4>[ 254.193492] CPU: 1 PID: 5309 Comm: rtcwake Not tainted 5.12.0-rc1-CI-CI_DRM_9834+ #1 <4>[ 254.193514] Hardware name: Google Soraka/Soraka, BIOS MrChromebox-4.10 08/25/2019 <4>[ 254.193524] Call Trace: <4>[ 254.193536] dump_stack+0x7f/0xad <4>[ 254.193567] mark_lock.part.47+0x8ca/0xce0 <4>[ 254.193604] __lock_acquire+0x39b/0x2590 <4>[ 254.193626] ? asm_sysvec_apic_timer_interrupt+0x12/0x20 <4>[ 254.193660] lock_acquire+0xd1/0x3d0 <4>[ 254.193677] ? cmos_interrupt+0x18/0x100 <4>[ 254.193716] _raw_spin_lock+0x2a/0x40 <4>[ 254.193735] ? cmos_interrupt+0x18/0x100 <4>[ 254.193758] cmos_interrupt+0x18/0x100 <4>[ 254.193785] cmos_resume+0x2ac/0x2d0 <4>[ 254.193813] ? acpi_pm_set_device_wakeup+0x1f/0x110 <4>[ 254.193842] ? pnp_bus_suspend+0x10/0x10 <4>[ 254.193864] pnp_bus_resume+0x5e/0x90 <4>[ 254.193885] dpm_run_callback+0x5f/0x240 <4>[ 254.193914] device_resume+0xb2/0x1e0 <4>[ 254.193942] ? pm_dev_err+0x25/0x25 <4>[ 254.193974] dpm_resume+0xea/0x3f0 <4>[ 254.194005] dpm_resume_end+0x8/0x10 <4>[ 254.194030] suspend_devices_and_enter+0x29b/0xaa0 <4>[ 254.194066] pm_suspend.cold.8+0x301/0x34a <4>[ 254.194094] state_store+0x7b/0xe0 <4>[ 254.194124] kernfs_fop_write_iter+0x11d/0x1c0 <4>[ 254.194151] new_sync_write+0x11d/0x1b0 <4>[ 254.194183] vfs_write+0x265/0x390 <4>[ 254.194207] ksys_write+0x5a/0xd0 <4>[ 254.194232] do_syscall_64+0x33/0x80 <4>[ 254.194251] entry_SYSCALL_64_after_hwframe+0x44/0xae <4>[ 254.194274] RIP: 0033:0x7f07d79691e7 <4>[ 254.194293] Code: 64 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24 <4>[ 254.194312] RSP: 002b:00007ffd9cc2c768 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 <4>[ 254.194337] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f07d79691e7 <4>[ 254.194352] RDX: 0000000000000004 RSI: 0000556ebfc63590 RDI: 000000000000000b <4>[ 254.194366] RBP: 0000556ebfc63590 R08: 0000000000000000 R09: 0000000000000004 <4>[ 254.194379] R10: 0000556ebf0ec2a6 R11: 0000000000000246 R12: 0000000000000004 which breaks S3-resume on fi-kbl-soraka presumably as that's slow enough to trigger the alarm during the suspend. Fixes: 6950d04 ("rtc: cmos: Replace spin_lock_irqsave with spin_lock in hard IRQ") References: 66e4f4a ("rtc: cmos: Use spin_lock_irqsave() in cmos_interrupt()"): Signed-off-by: Chris Wilson <[email protected]> Cc: Xiaofei Tan <[email protected]> Cc: Alexandre Belloni <[email protected]> Cc: Alessandro Zummo <[email protected]> Cc: Ville Syrjälä <[email protected]> Reviewed-by: Ville Syrjälä <[email protected]> Signed-off-by: Alexandre Belloni <[email protected]> Link: https://lore.kernel.org/r/[email protected]

Variable mm->total_vm could be accessed concurrently during mmaping and system accounting as noticed by KCSAN, BUG: KCSAN: data-race in __acct_update_integrals / mmap_region read-write to 0xffffa40267bd14c8 of 8 bytes by task 15609 on cpu 3: mmap_region+0x6dc/0x1400 do_mmap+0x794/0xca0 vm_mmap_pgoff+0xdf/0x150 ksys_mmap_pgoff+0xe1/0x380 do_syscall_64+0x37/0x50 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffffa40267bd14c8 of 8 bytes by interrupt on cpu 2: __acct_update_integrals+0x187/0x1d0 acct_account_cputime+0x3c/0x40 update_process_times+0x5c/0x150 tick_sched_timer+0x184/0x210 __run_hrtimer+0x119/0x3b0 hrtimer_interrupt+0x350/0xaa0 __sysvec_apic_timer_interrupt+0x7b/0x220 asm_call_irq_on_stack+0x12/0x20 sysvec_apic_timer_interrupt+0x4d/0x80 asm_sysvec_apic_timer_interrupt+0x12/0x20 smp_call_function_single+0x192/0x2b0 perf_install_in_context+0x29b/0x4a0 __se_sys_perf_event_open+0x1a98/0x2550 __x64_sys_perf_event_open+0x63/0x70 do_syscall_64+0x37/0x50 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 2 PID: 15610 Comm: syz-executor.3 Not tainted 5.10.0+ #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 In vm_stat_account which called by mmap_region, increase total_vm, and __acct_update_integrals may read total_vm at the same time. This will cause a data race which lead to undefined behaviour. To avoid potential bad read/write, volatile property and barrier are both used to avoid undefined behaviour. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Peng Liu <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Stephen Rothwell <[email protected]>

KCSAN reports a data-race on v5.10 which also exists on mainline: ================================================================== BUG: KCSAN: data-race in extfrag_for_order+0x33/0x2d0 race at unknown origin, with read to 0xffff9ee9bfffab48 of 8 bytes by task 34 on cpu 1: extfrag_for_order+0x33/0x2d0 kcompactd+0x5f0/0xce0 kthread+0x1f9/0x220 ret_from_fork+0x22/0x30 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 34 Comm: kcompactd0 Not tainted 5.10.0+ #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 ================================================================== Access to zone->free_area[order].nr_free in extfrag_for_order()/frag_show_print() is lockless. That's intentional and the stats are a rough estimate anyway. Annotate them with data_race(). Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Liu Shixin <[email protected]> Cc: "Paul E . McKenney" <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Stephen Rothwell <[email protected]>

#2

Coverity warns uf an unused value: CID 44865 (#2 of 2): Unused value (UNUSED_VALUE) assigned_value: Assigning value -14 to ret here, but that stored value is overwritten before it can be used. 2006 int ret = -EFAULT; ... value_overwrite: Overwriting previous write to ret with value from drbg_seed(drbg, &addtl, false). 2052 ret = drbg_seed(drbg, &addtl, false); Fix this by removing the variable initializer. Cc: Herbert Xu <[email protected]> Cc: "David S. Miller" <[email protected]> Cc: [email protected] Cc: [email protected] Signed-off-by: Tim Gardner <[email protected]> Signed-off-by: Herbert Xu <[email protected]>

i915 will soon gain an eviction path that trylock a whole lot of locks for eviction, getting dmesg failures like below: BUG: MAX_LOCK_DEPTH too low! turning off the locking correctness validator. depth: 48 max: 48! 48 locks held by i915_selftest/5776: #0: ffff888101a79240 (&dev->mutex){....}-{3:3}, at: __driver_attach+0x88/0x160 #1: ffffc900009778c0 (reservation_ww_class_acquire){+.+.}-{0:0}, at: i915_vma_pin.constprop.63+0x39/0x1b0 [i915] #2: ffff88800cf74de8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_vma_pin.constprop.63+0x5f/0x1b0 [i915] #3: ffff88810c7f9e38 (&vm->mutex/1){+.+.}-{3:3}, at: i915_vma_pin_ww+0x1c4/0x9d0 [i915] #4: ffff88810bad5768 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915] #5: ffff88810bad60e8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915] ... torvalds#46: ffff88811964d768 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915] torvalds#47: ffff88811964e0e8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915] INFO: lockdep is turned off. Fixing eviction to nest into ww_class_acquire is a high priority, but it requires a rework of the entire driver, which can only be done one step at a time. As an intermediate solution, add an acquire context to ww_mutex_trylock, which allows us to do proper nesting annotations on the trylocks, making the above lockdep splat disappear. This is also useful in regulator_lock_nested, which may avoid dropping regulator_nesting_mutex in the uncontended path, so use it there. TTM may be another user for this, where we could lock a buffer in a fastpath with list locks held, without dropping all locks we hold. [peterz: rework actual ww_mutex_trylock() implementations] Signed-off-by: Maarten Lankhorst <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Link: https://lkml.kernel.org/r/[email protected]

It's later supposed to be either a correct address or NULL. Without the initialization, it may contain an undefined value which results in the following segmentation fault: # perf top --sort comm -g --ignore-callees=do_idle terminates with: #0 0x00007ffff56b7685 in __strlen_avx2 () from /lib64/libc.so.6 #1 0x00007ffff55e3802 in strdup () from /lib64/libc.so.6 #2 0x00005555558cb139 in hist_entry__init (callchain_size=<optimized out>, sample_self=true, template=0x7fffde7fb110, he=0x7fffd801c250) at util/hist.c:489 #3 hist_entry__new (template=template@entry=0x7fffde7fb110, sample_self=sample_self@entry=true) at util/hist.c:564 #4 0x00005555558cb4ba in hists__findnew_entry (hists=hists@entry=0x5555561d9e38, entry=entry@entry=0x7fffde7fb110, al=al@entry=0x7fffde7fb420, sample_self=sample_self@entry=true) at util/hist.c:657 #5 0x00005555558cba1b in __hists__add_entry (hists=hists@entry=0x5555561d9e38, al=0x7fffde7fb420, sym_parent=<optimized out>, bi=bi@entry=0x0, mi=mi@entry=0x0, sample=sample@entry=0x7fffde7fb4b0, sample_self=true, ops=0x0, block_info=0x0) at util/hist.c:288 torvalds#6 0x00005555558cbb70 in hists__add_entry (sample_self=true, sample=0x7fffde7fb4b0, mi=0x0, bi=0x0, sym_parent=<optimized out>, al=<optimized out>, hists=0x5555561d9e38) at util/hist.c:1056 torvalds#7 iter_add_single_cumulative_entry (iter=0x7fffde7fb460, al=<optimized out>) at util/hist.c:1056 torvalds#8 0x00005555558cc8a4 in hist_entry_iter__add (iter=iter@entry=0x7fffde7fb460, al=al@entry=0x7fffde7fb420, max_stack_depth=<optimized out>, arg=arg@entry=0x7fffffff7db0) at util/hist.c:1231 torvalds#9 0x00005555557cdc9a in perf_event__process_sample (machine=<optimized out>, sample=0x7fffde7fb4b0, evsel=<optimized out>, event=<optimized out>, tool=0x7fffffff7db0) at builtin-top.c:842 torvalds#10 deliver_event (qe=<optimized out>, qevent=<optimized out>) at builtin-top.c:1202 torvalds#11 0x00005555558a9318 in do_flush (show_progress=false, oe=0x7fffffff80e0) at util/ordered-events.c:244 torvalds#12 __ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP, timestamp=timestamp@entry=0) at util/ordered-events.c:323 torvalds#13 0x00005555558a9789 in __ordered_events__flush (timestamp=<optimized out>, how=<optimized out>, oe=<optimized out>) at util/ordered-events.c:339 torvalds#14 ordered_events__flush (how=OE_FLUSH__TOP, oe=0x7fffffff80e0) at util/ordered-events.c:341 torvalds#15 ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP) at util/ordered-events.c:339 torvalds#16 0x00005555557cd631 in process_thread (arg=0x7fffffff7db0) at builtin-top.c:1114 torvalds#17 0x00007ffff7bb817a in start_thread () from /lib64/libpthread.so.0 torvalds#18 0x00007ffff5656dc3 in clone () from /lib64/libc.so.6 If you look at the frame #2, the code is: 488 if (he->srcline) { 489 he->srcline = strdup(he->srcline); 490 if (he->srcline == NULL) 491 goto err_rawdata; 492 } If he->srcline is not NULL (it is not NULL if it is uninitialized rubbish), it gets strdupped and strdupping a rubbish random string causes the problem. Also, if you look at the commit 1fb7d06, it adds the srcline property into the struct, but not initializing it everywhere needed. Committer notes: Now I see, when using --ignore-callees=do_idle we end up here at line 2189 in add_callchain_ip(): 2181 if (al.sym != NULL) { 2182 if (perf_hpp_list.parent && !*parent && 2183 symbol__match_regex(al.sym, &parent_regex)) 2184 *parent = al.sym; 2185 else if (have_ignore_callees && root_al && 2186 symbol__match_regex(al.sym, &ignore_callees_regex)) { 2187 /* Treat this symbol as the root, 2188 forgetting its callees. */ 2189 *root_al = al; 2190 callchain_cursor_reset(cursor); 2191 } 2192 } And the al that doesn't have the ->srcline field initialized will be copied to the root_al, so then, back to: 1211 int hist_entry_iter__add(struct hist_entry_iter *iter, struct addr_location *al, 1212 int max_stack_depth, void *arg) 1213 { 1214 int err, err2; 1215 struct map *alm = NULL; 1216 1217 if (al) 1218 alm = map__get(al->map); 1219 1220 err = sample__resolve_callchain(iter->sample, &callchain_cursor, &iter->parent, 1221 iter->evsel, al, max_stack_depth); 1222 if (err) { 1223 map__put(alm); 1224 return err; 1225 } 1226 1227 err = iter->ops->prepare_entry(iter, al); 1228 if (err) 1229 goto out; 1230 1231 err = iter->ops->add_single_entry(iter, al); 1232 if (err) 1233 goto out; 1234 That al at line 1221 is what hist_entry_iter__add() (called from sample__resolve_callchain()) saw as 'root_al', and then: iter->ops->add_single_entry(iter, al); will go on with al->srcline with a bogus value, I'll add the above sequence to the cset and apply, thanks! Signed-off-by: Michael Petlan <[email protected]> CC: Milian Wolff <[email protected]> Cc: Jiri Olsa <[email protected]> Fixes: 1fb7d06 ("perf report Use srcline from callchain for hist entries") Link: https //lore.kernel.org/r/[email protected] Reported-by: Juri Lelli <[email protected]> Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

FD uses xyarray__entry that may return NULL if an index is out of bounds. If NULL is returned then a segv happens as FD unconditionally dereferences the pointer. This was happening in a case of with perf iostat as shown below. The fix is to make FD an "int*" rather than an int and handle the NULL case as either invalid input or a closed fd. $ sudo gdb --args perf stat --iostat list ... Breakpoint 1, perf_evsel__alloc_fd (evsel=0x5555560951a0, ncpus=1, nthreads=1) at evsel.c:50 50 { (gdb) bt #0 perf_evsel__alloc_fd (evsel=0x5555560951a0, ncpus=1, nthreads=1) at evsel.c:50 #1 0x000055555585c188 in evsel__open_cpu (evsel=0x5555560951a0, cpus=0x555556093410, threads=0x555556086fb0, start_cpu=0, end_cpu=1) at util/evsel.c:1792 #2 0x000055555585cfb2 in evsel__open (evsel=0x5555560951a0, cpus=0x0, threads=0x555556086fb0) at util/evsel.c:2045 #3 0x000055555585d0db in evsel__open_per_thread (evsel=0x5555560951a0, threads=0x555556086fb0) at util/evsel.c:2065 #4 0x00005555558ece64 in create_perf_stat_counter (evsel=0x5555560951a0, config=0x555555c34700 <stat_config>, target=0x555555c2f1c0 <target>, cpu=0) at util/stat.c:590 #5 0x000055555578e927 in __run_perf_stat (argc=1, argv=0x7fffffffe4a0, run_idx=0) at builtin-stat.c:833 torvalds#6 0x000055555578f3c6 in run_perf_stat (argc=1, argv=0x7fffffffe4a0, run_idx=0) at builtin-stat.c:1048 torvalds#7 0x0000555555792ee5 in cmd_stat (argc=1, argv=0x7fffffffe4a0) at builtin-stat.c:2534 torvalds#8 0x0000555555835ed3 in run_builtin (p=0x555555c3f540 <commands+288>, argc=3, argv=0x7fffffffe4a0) at perf.c:313 torvalds#9 0x0000555555836154 in handle_internal_command (argc=3, argv=0x7fffffffe4a0) at perf.c:365 torvalds#10 0x000055555583629f in run_argv (argcp=0x7fffffffe2ec, argv=0x7fffffffe2e0) at perf.c:409 torvalds#11 0x0000555555836692 in main (argc=3, argv=0x7fffffffe4a0) at perf.c:539 ... (gdb) c Continuing. Error: The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (uncore_iio_0/event=0x83,umask=0x04,ch_mask=0xF,fc_mask=0x07/). /bin/dmesg | grep -i perf may provide additional information. Program received signal SIGSEGV, Segmentation fault. 0x00005555559b03ea in perf_evsel__close_fd_cpu (evsel=0x5555560951a0, cpu=1) at evsel.c:166 166 if (FD(evsel, cpu, thread) >= 0) v3. fixes a bug in perf_evsel__run_ioctl where the sense of a branch was backward. Signed-off-by: Ian Rogers <[email protected]> Acked-by: Jiri Olsa <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Stephane Eranian <[email protected]> Link: http://lore.kernel.org/lkml/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

#2

Implement an alternative to using the netfslib-base I/O API so that we can move forwards on getting rid of the old API. Note that this API is should not be used by new filesystems as it still uses the backing filesystem to track unfilled holes in the backing file, though using SEEK_DATA/SEEK_HOLE rather than bmap(). This is dangerous and can lead to corrupted data as the backing filesystem cannot be relied on not to fill in holes with blocks of zeros in order to optimise an extent list[1]. It may also punch out blocks of zeros to create holes for the same reason, but this is less of a problem. Also adjust the macros that must be defined to indicate which API is to be used: (*) FSCACHE_USE_OLD_IO_API - Use the current upstream API. This will be deleted. (*) FSCACHE_USE_FALLBACK_IO_API - Use the API added here. (*) FSCACHE_USE_NEW_IO_API - Use the new API or netfs API. Changes ======= ver #2: - Changed "deprecated" to "fallback" in the new function names[2]. - Need to define FSCACHE_USE_FALLBACK_IO_API in fscache/io.c to enable the prototypes of the functions[3]. - Removed a couple of unused variables[3]. - Make netfs/read_helpers.c use NETFS_READ_HOLE_*. Signed-off-by: David Howells <[email protected]> Tested-by: Dave Wysochanski <[email protected]> cc: [email protected] Link: https://lore.kernel.org/r/[email protected]/ [1] Link: https://lore.kernel.org/r/CAHk-=wiVK+1CyEjW8u71zVPK8msea=qPpznX35gnX+s8sXnJTg@mail.gmail.com/ [2] Link: https://lore.kernel.org/r/[email protected]/ [3] Link: https://lore.kernel.org/r/163162770137.438332.13788466444753625553.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/163189107352.2509237.759630157032861275.stgit@warthog.procyon.org.uk/ # rfc v2

Move NFS to using the alternate fallback fscache I/O API instead of the old upstream I/O API as that is about to be deleted. The alternate API will also be deleted at some point in the future as it's dangerous (as is the old API) and can lead to data corruption if the backing filesystem can insert/remove bridging blocks of zeros into its extent list[1]. The alternate API reads and writes pages synchronously, with the intention of allowing removal of the operation management framework and thence the object management framework from fscache. The preferred change would be to use the netfs lib, but the new I/O API can be used directly. It's just that as the cache now needs to track data for itself, caching blocks may exceed page size... Changes ======= ver #2: - Changed "deprecated" to "fallback" in the new function names[2]. Signed-off-by: David Howells <[email protected]> Tested-by: Dave Wysochanski <[email protected]> cc: Trond Myklebust <[email protected]> cc: Anna Schumaker <[email protected]> cc: [email protected] cc: [email protected] Link: https://lore.kernel.org/r/[email protected] [1] Link: https://lore.kernel.org/r/CAHk-=wiVK+1CyEjW8u71zVPK8msea=qPpznX35gnX+s8sXnJTg@mail.gmail.com/ [2] Link: https://lore.kernel.org/r/163162771421.438332.11563297618174948818.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/163189108292.2509237.12615909591150927232.stgit@warthog.procyon.org.uk/ # rfc v2

Move cifs/smb to using the alternate fallback fscache I/O API instead of the old upstream I/O API as that is about to be deleted. The alternate API will also be deleted at some point in the future as it's dangerous (as is the old API) and can lead to data corruption if the backing filesystem can insert/remove bridging blocks of zeros into its extent list[1]. The alternate API reads and writes pages synchronously, with the intention of allowing removal of the operation management framework and thence the object management framework from fscache. The preferred change would be to use the netfs lib, but the new I/O API can be used directly. It's just that as the cache now needs to track data for itself, caching blocks may exceed page size... Changes ======= ver #2: - Changed "deprecated" to "fallback" in the new function names[2]. Signed-off-by: David Howells <[email protected]> cc: Steve French <[email protected]> cc: Shyam Prasad N <[email protected]> cc: [email protected] cc: [email protected] Link: https://lore.kernel.org/r/[email protected] [1] Link: https://lore.kernel.org/r/CAHk-=wiVK+1CyEjW8u71zVPK8msea=qPpznX35gnX+s8sXnJTg@mail.gmail.com/ [2] Link: https://lore.kernel.org/r/163162773867.438332.3585429891151112562.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/163189112708.2509237.17528578040344723638.stgit@warthog.procyon.org.uk/ # rfc v2

Update the fscache documentation to remove the old I/O API bits and to note the new fallback API. Changes ======= ver #2: - Changed "deprecated" to "fallback" in the new function names[1]. Signed-off-by: David Howells <[email protected]> cc: [email protected] Link: https://lore.kernel.org/r/CAHk-=wiVK+1CyEjW8u71zVPK8msea=qPpznX35gnX+s8sXnJTg@mail.gmail.com/ [1] Link: https://lore.kernel.org/r/163162778200.438332.1918683687532006409.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/163189115518.2509237.6454712882112339524.stgit@warthog.procyon.org.uk/ # rfc v2

Variable mm->total_vm could be accessed concurrently during mmaping and system accounting as noticed by KCSAN, BUG: KCSAN: data-race in __acct_update_integrals / mmap_region read-write to 0xffffa40267bd14c8 of 8 bytes by task 15609 on cpu 3: mmap_region+0x6dc/0x1400 do_mmap+0x794/0xca0 vm_mmap_pgoff+0xdf/0x150 ksys_mmap_pgoff+0xe1/0x380 do_syscall_64+0x37/0x50 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffffa40267bd14c8 of 8 bytes by interrupt on cpu 2: __acct_update_integrals+0x187/0x1d0 acct_account_cputime+0x3c/0x40 update_process_times+0x5c/0x150 tick_sched_timer+0x184/0x210 __run_hrtimer+0x119/0x3b0 hrtimer_interrupt+0x350/0xaa0 __sysvec_apic_timer_interrupt+0x7b/0x220 asm_call_irq_on_stack+0x12/0x20 sysvec_apic_timer_interrupt+0x4d/0x80 asm_sysvec_apic_timer_interrupt+0x12/0x20 smp_call_function_single+0x192/0x2b0 perf_install_in_context+0x29b/0x4a0 __se_sys_perf_event_open+0x1a98/0x2550 __x64_sys_perf_event_open+0x63/0x70 do_syscall_64+0x37/0x50 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 2 PID: 15610 Comm: syz-executor.3 Not tainted 5.10.0+ #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 In vm_stat_account which called by mmap_region, increase total_vm, and __acct_update_integrals may read total_vm at the same time. This will cause a data race which lead to undefined behaviour. To avoid potential bad read/write, volatile property and barrier are both used to avoid undefined behaviour. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Peng Liu <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Stephen Rothwell <[email protected]>

KCSAN reports a data-race on v5.10 which also exists on mainline: ================================================================== BUG: KCSAN: data-race in extfrag_for_order+0x33/0x2d0 race at unknown origin, with read to 0xffff9ee9bfffab48 of 8 bytes by task 34 on cpu 1: extfrag_for_order+0x33/0x2d0 kcompactd+0x5f0/0xce0 kthread+0x1f9/0x220 ret_from_fork+0x22/0x30 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 34 Comm: kcompactd0 Not tainted 5.10.0+ #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 ================================================================== Access to zone->free_area[order].nr_free in extfrag_for_order()/frag_show_print() is lockless. That's intentional and the stats are a rough estimate anyway. Annotate them with data_race(). Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Liu Shixin <[email protected]> Cc: "Paul E . McKenney" <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Stephen Rothwell <[email protected]>

Andrii Nakryiko says: ==================== Implement libbpf support for attaching uprobes/uretprobes using legacy tracefs interfaces. This is a logical complement to recently landed legacy kprobe support ([0]). This patch refactors existing legacy kprobe code to be more uniform with uprobe code as well, making the logic easier to compare and follow. This patch set also fixes two bugs recently found by Coverity in legacy kprobe handling code, and thus subsumes previously submitted two patches ([1]): original patch #1 is kept as is, while original patch #2 was dropped because patch #3 of the current series refactors and fixes affected code. [0] https://patchwork.kernel.org/project/netdevbpf/patch/[email protected]/ [1] https://patchwork.kernel.org/project/netdevbpf/list/?series=549977&state=* v1->v2: - drop 'legacy = true' debug left-over and explain legacy check (Alexei). ==================== Signed-off-by: Alexei Starovoitov <[email protected]>

Ido Schimmel says: ==================== mlxsw: Alter trap adjacency entry allocation scheme In commit 0c3cbbf ("mlxsw: Add specific trap for packets routed via invalid nexthops"), mlxsw started allocating a new adjacency entry during driver initialization, to trap packets routed via invalid nexthops. This behavior was later altered in commit 983db61 ("mlxsw: spectrum_router: Allocate discard adjacency entry when needed") to only allocate the entry upon the first route that requires it. The motivation for the change is explained in the commit message. The problem with the current behavior is that the entry shows up as a "leak" in a new BPF resource monitoring tool [1]. This is caused by the asymmetry of the allocation/free scheme. While the entry is allocated upon the first route that requires it, it is only freed during de-initialization of the driver. Instead, this patchset tracks the number of active nexthop groups and allocates the adjacency entry upon the creation of the first group. The entry is freed when the number of active groups reaches zero. Patch #1 adds the new entry. Patch #2 converts mlxsw to start using the new entry and removes the old one. ==================== Signed-off-by: David S. Miller <[email protected]>

#2

pipcet added 30 commits August 10, 2021 15:03

duplicate AIC driver as irq-apple-fiq.c

cc475e5

delete IRQ stuff from FIQ driver

99e3e01

delete FIQ stuff from IRQ driver

5d69304

remove more IRQ stuff from FIQ driver

5e3e99a

remove more IRQ stuff from FIQ driver

77896b2

remove more IRQ stuff from FIQ driver

911a0b3

FIQ cleanup

4be2189

TEMPORARY hack to build FIQ driver

8b437d3

compilation fixes

e76788d

TEMPORARY DT entries

ae64c3e

minor things

566b0ba

TEMPORARY hack since FIQs aren't masked properly yet.

58d1214

initialize CPUs properly

de52b6b

undo temporary hack

1dabd80

rm inappropriate message

1df1de8

fix the bug @svenpeter42 found.

8332d9f

duplicate code

c47660c

prepare the funneling driver

4820a22

still hoping for a negative diffstat

db0fca9

remove the vIPI implementation

c7a8013

minor

051e9f7

comments

605c9f7

comments

7235b1b

whitespace

88c6ef9

rename ipi-funnel to vipi

7ccd8ec

rename ipi-funnel to vipi

8f33c22

more renaming

6ada2b7

cleanup

be45284

allow multi-CPU affinities

93edc61

handle only a single IRQ event at a time

7a7bfa9

pipcet added a commit that referenced this pull request Sep 13, 2021

arch/arm64/kernel/head.S: {cpuinit} arch/arm64/kernel/head.S:

6a41c30

#2

pipcet added a commit that referenced this pull request Sep 13, 2021

arch/arm64/kernel/Makefile: {cpustart} arch/arm64/kernel/Makefile:

ac6bde1

#2

pipcet added a commit that referenced this pull request Sep 15, 2021

arch/arm64/kernel/head.S: {cpuinit} arch/arm64/kernel/head.S:

9279407

#2

pipcet added a commit that referenced this pull request Sep 15, 2021

arch/arm64/kernel/Makefile: {cpustart} arch/arm64/kernel/Makefile:

da0b628

#2

pipcet added a commit that referenced this pull request Sep 17, 2021

arch/arm64/kernel/head.S: {cpuinit} arch/arm64/kernel/head.S:

1ca7831

#2

pipcet added a commit that referenced this pull request Sep 17, 2021

arch/arm64/kernel/Makefile: {cpustart} arch/arm64/kernel/Makefile:

a00e4fd

#2

pipcet added a commit that referenced this pull request Sep 20, 2021

arch/arm64/kernel/head.S: {cpuinit} arch/arm64/kernel/head.S:

0399105

#2

pipcet added a commit that referenced this pull request Sep 20, 2021

arch/arm64/kernel/Makefile: {cpustart} arch/arm64/kernel/Makefile:

d2dbfce

#2

pipcet added a commit that referenced this pull request Sep 23, 2021

arch/arm64/kernel/head.S: {cpuinit} arch/arm64/kernel/head.S:

b352b03

#2

pipcet added a commit that referenced this pull request Sep 23, 2021

arch/arm64/kernel/Makefile: {cpustart} arch/arm64/kernel/Makefile:

07f6c8e

#2

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UNTESTED AIC driver cleanup/reorg #2

UNTESTED AIC driver cleanup/reorg #2

pipcet commented Aug 11, 2021

UNTESTED AIC driver cleanup/reorg #2

UNTESTED AIC driver cleanup/reorg #2

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pipcet commented Aug 11, 2021