Doc improvements #35
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Doc improvements #35
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Includes the bit on conditional compilation from [1]. [1] #32 (comment) Signed-off-by: Miguel Ojeda <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
alex
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Nov 28, 2020
ojeda
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Nov 28, 2020
Get and put the reference to the ctrl in the nvme_dev_open() and nvme_dev_release() before and after module get/put for ctrl in char device file operations. Introduce char_dev relase function, get/put the controller and module which allows us to fix the potential Oops which can be easily reproduced with a passthru ctrl (although the problem also exists with pure user access): Entering kdb (current=0xffff8887f8290000, pid 3128) on processor 30 Oops: (null) due to oops @ 0xffffffffa01019ad CPU: 30 PID: 3128 Comm: bash Tainted: G W OE 5.8.0-rc4nvme-5.9+ #35 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.4 RIP: 0010:nvme_free_ctrl+0x234/0x285 [nvme_core] Code: 57 10 a0 e8 73 bf 02 e1 ba 3d 11 00 00 48 c7 c6 98 33 10 a0 48 c7 c7 1d 57 10 a0 e8 5b bf 02 e1 8 RSP: 0018:ffffc90001d63de0 EFLAGS: 00010246 RAX: ffffffffa05c0440 RBX: ffff8888119e45a0 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff8888177e9550 RDI: ffff8888119e43b0 RBP: ffff8887d4768000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffc90001d63c90 R12: ffff8888119e43b0 R13: ffff8888119e5108 R14: dead000000000100 R15: ffff8888119e5108 FS: 00007f1ef27b0740(0000) GS:ffff888817600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffa05c0470 CR3: 00000007f6bee000 CR4: 00000000003406e0 Call Trace: device_release+0x27/0x80 kobject_put+0x98/0x170 nvmet_passthru_ctrl_disable+0x4a/0x70 [nvmet] nvmet_passthru_enable_store+0x4c/0x90 [nvmet] configfs_write_file+0xe6/0x150 vfs_write+0xba/0x1e0 ksys_write+0x5f/0xe0 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f1ef1eb2840 Code: Bad RIP value. RSP: 002b:00007fffdbff0eb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f1ef1eb2840 RDX: 0000000000000002 RSI: 00007f1ef27d2000 RDI: 0000000000000001 RBP: 00007f1ef27d2000 R08: 000000000000000a R09: 00007f1ef27b0740 R10: 0000000000000001 R11: 0000000000000246 R12: 00007f1ef2186400 R13: 0000000000000002 R14: 0000000000000001 R15: 0000000000000000 With this patch fix we take the module ref count in nvme_dev_open() and release that ref count in newly introduced nvme_dev_release(). Signed-off-by: Chaitanya Kulkarni <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]>
ojeda
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Mar 14, 2022
After enabling CONFIG_SCHED_CORE (landed during 5.14 cycle), 2-core 2-thread-per-core interAptiv (CPS-driven) started emitting the following: [ 0.025698] CPU1 revision is: 0001a120 (MIPS interAptiv (multi)) [ 0.048183] ------------[ cut here ]------------ [ 0.048187] WARNING: CPU: 1 PID: 0 at kernel/sched/core.c:6025 sched_core_cpu_starting+0x198/0x240 [ 0.048220] Modules linked in: [ 0.048233] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.17.0-rc3+ #35 b7b319f24073fd9a3c2aa7ad15fb7993eec0b26f [ 0.048247] Stack : 817f0000 00000004 327804c8 810eb050 00000000 00000004 00000000 c314fdd1 [ 0.048278] 830cbd64 819c0000 81800000 817f0000 83070bf4 00000001 830cbd08 00000000 [ 0.048307] 00000000 00000000 815fcbc4 00000000 00000000 00000000 00000000 00000000 [ 0.048334] 00000000 00000000 00000000 00000000 817f0000 00000000 00000000 817f6f34 [ 0.048361] 817f0000 818a3c00 817f0000 00000004 00000000 00000000 4dc33260 0018c933 [ 0.048389] ... [ 0.048396] Call Trace: [ 0.048399] [<8105a7bc>] show_stack+0x3c/0x140 [ 0.048424] [<8131c2a0>] dump_stack_lvl+0x60/0x80 [ 0.048440] [<8108b5c0>] __warn+0xc0/0xf4 [ 0.048454] [<8108b658>] warn_slowpath_fmt+0x64/0x10c [ 0.048467] [<810bd418>] sched_core_cpu_starting+0x198/0x240 [ 0.048483] [<810c6514>] sched_cpu_starting+0x14/0x80 [ 0.048497] [<8108c0f8>] cpuhp_invoke_callback_range+0x78/0x140 [ 0.048510] [<8108d914>] notify_cpu_starting+0x94/0x140 [ 0.048523] [<8106593c>] start_secondary+0xbc/0x280 [ 0.048539] [ 0.048543] ---[ end trace 0000000000000000 ]--- [ 0.048636] Synchronize counters for CPU 1: done. ...for each but CPU 0/boot. Basic debug printks right before the mentioned line say: [ 0.048170] CPU: 1, smt_mask: So smt_mask, which is sibling mask obviously, is empty when entering the function. This is critical, as sched_core_cpu_starting() calculates core-scheduling parameters only once per CPU start, and it's crucial to have all the parameters filled in at that moment (at least it uses cpu_smt_mask() which in fact is `&cpu_sibling_map[cpu]` on MIPS). A bit of debugging led me to that set_cpu_sibling_map() performing the actual map calculation, was being invocated after notify_cpu_start(), and exactly the latter function starts CPU HP callback round (sched_core_cpu_starting() is basically a CPU HP callback). While the flow is same on ARM64 (maps after the notifier, although before calling set_cpu_online()), x86 started calculating sibling maps earlier than starting the CPU HP callbacks in Linux 4.14 (see [0] for the reference). Neither me nor my brief tests couldn't find any potential caveats in calculating the maps right after performing delay calibration, but the WARN splat is now gone. The very same debug prints now yield exactly what I expected from them: [ 0.048433] CPU: 1, smt_mask: 0-1 [0] https://git.kernel.org/pub/scm/linux/kernel/git/mips/linux.git/commit/?id=76ce7cfe35ef Signed-off-by: Alexander Lobakin <[email protected]> Reviewed-by: Philippe Mathieu-Daudé <[email protected]> Signed-off-by: Thomas Bogendoerfer <[email protected]>
Darksonn
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Oct 19, 2022
Inspired by commit 9fb7410("arm64/BUG: Use BRK instruction for generic BUG traps"), do similar for LoongArch to use generic BUG() handler. This patch uses the BREAK software breakpoint instruction to generate a trap instead, similarly to most other arches, with the generic BUG code generating the dmesg boilerplate. This allows bug metadata to be moved to a separate table and reduces the amount of inline code at BUG() and WARN() sites. This also avoids clobbering any registers before they can be dumped. To mitigate the size of the bug table further, this patch makes use of the existing infrastructure for encoding addresses within the bug table as 32-bit relative pointers instead of absolute pointers. (Note: this limits the max kernel size to 2GB.) Before patch: [ 3018.338013] lkdtm: Performing direct entry BUG [ 3018.342445] Kernel bug detected[Rust-for-Linux#5]: [ 3018.345992] CPU: 2 PID: 865 Comm: cat Tainted: G D 6.0.0-rc6+ Rust-for-Linux#35 After patch: [ 125.585985] lkdtm: Performing direct entry BUG [ 125.590433] ------------[ cut here ]------------ [ 125.595020] kernel BUG at drivers/misc/lkdtm/bugs.c:78! [ 125.600211] Oops - BUG[Rust-for-Linux#1]: [ 125.602980] CPU: 3 PID: 410 Comm: cat Not tainted 6.0.0-rc6+ Rust-for-Linux#36 Out-of-line file/line data information obtained compared to before. Signed-off-by: Youling Tang <[email protected]> Signed-off-by: Huacai Chen <[email protected]>
ojeda
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Jul 19, 2023
With some IPv6 Ext Hdr (RPL, SRv6, etc.), we can send a packet that has the link-local address as src and dst IP and will be forwarded to an external IP in the IPv6 Ext Hdr. For example, the script below generates a packet whose src IP is the link-local address and dst is updated to 11::. # for f in $(find /proc/sys/net/ -name *seg6_enabled*); do echo 1 > $f; done # python3 >>> from socket import * >>> from scapy.all import * >>> >>> SRC_ADDR = DST_ADDR = "fe80::5054:ff:fe12:3456" >>> >>> pkt = IPv6(src=SRC_ADDR, dst=DST_ADDR) >>> pkt /= IPv6ExtHdrSegmentRouting(type=4, addresses=["11::", "22::"], segleft=1) >>> >>> sk = socket(AF_INET6, SOCK_RAW, IPPROTO_RAW) >>> sk.sendto(bytes(pkt), (DST_ADDR, 0)) For such a packet, we call ip6_route_input() to look up a route for the next destination in these three functions depending on the header type. * ipv6_rthdr_rcv() * ipv6_rpl_srh_rcv() * ipv6_srh_rcv() If no route is found, ip6_null_entry is set to skb, and the following dst_input(skb) calls ip6_pkt_drop(). Finally, in icmp6_dev(), we dereference skb_rt6_info(skb)->rt6i_idev->dev as the input device is the loopback interface. Then, we have to check if skb_rt6_info(skb)->rt6i_idev is NULL or not to avoid NULL pointer deref for ip6_null_entry. BUG: kernel NULL pointer dereference, address: 0000000000000000 PF: supervisor read access in kernel mode PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 0 PID: 157 Comm: python3 Not tainted 6.4.0-11996-gb121d614371c #35 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 RIP: 0010:icmp6_send (net/ipv6/icmp.c:436 net/ipv6/icmp.c:503) Code: fe ff ff 48 c7 40 30 c0 86 5d 83 e8 c6 44 1c 00 e9 c8 fc ff ff 49 8b 46 58 48 83 e0 fe 0f 84 4a fb ff ff 48 8b 80 d0 00 00 00 <48> 8b 00 44 8b 88 e0 00 00 00 e9 34 fb ff ff 4d 85 ed 0f 85 69 01 RSP: 0018:ffffc90000003c70 EFLAGS: 00000286 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 00000000000000e0 RDX: 0000000000000021 RSI: 0000000000000000 RDI: ffff888006d72a18 RBP: ffffc90000003d80 R08: 0000000000000000 R09: 0000000000000001 R10: ffffc90000003d98 R11: 0000000000000040 R12: ffff888006d72a10 R13: 0000000000000000 R14: ffff8880057fb800 R15: ffffffff835d86c0 FS: 00007f9dc72ee740(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000057b2000 CR4: 00000000007506f0 PKRU: 55555554 Call Trace: <IRQ> ip6_pkt_drop (net/ipv6/route.c:4513) ipv6_rthdr_rcv (net/ipv6/exthdrs.c:640 net/ipv6/exthdrs.c:686) ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:437 (discriminator 5)) ip6_input_finish (./include/linux/rcupdate.h:781 net/ipv6/ip6_input.c:483) __netif_receive_skb_one_core (net/core/dev.c:5455) process_backlog (./include/linux/rcupdate.h:781 net/core/dev.c:5895) __napi_poll (net/core/dev.c:6460) net_rx_action (net/core/dev.c:6529 net/core/dev.c:6660) __do_softirq (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/irq.h:142 kernel/softirq.c:554) do_softirq (kernel/softirq.c:454 kernel/softirq.c:441) </IRQ> <TASK> __local_bh_enable_ip (kernel/softirq.c:381) __dev_queue_xmit (net/core/dev.c:4231) ip6_finish_output2 (./include/net/neighbour.h:544 net/ipv6/ip6_output.c:135) rawv6_sendmsg (./include/net/dst.h:458 ./include/linux/netfilter.h:303 net/ipv6/raw.c:656 net/ipv6/raw.c:914) sock_sendmsg (net/socket.c:725 net/socket.c:748) __sys_sendto (net/socket.c:2134) __x64_sys_sendto (net/socket.c:2146 net/socket.c:2142 net/socket.c:2142) do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) RIP: 0033:0x7f9dc751baea Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 f3 0f 1e fa 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 15 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 7e c3 0f 1f 44 00 00 41 54 48 83 ec 30 44 89 RSP: 002b:00007ffe98712c38 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007ffe98712cf8 RCX: 00007f9dc751baea RDX: 0000000000000060 RSI: 00007f9dc6460b90 RDI: 0000000000000003 RBP: 00007f9dc56e8be0 R08: 00007ffe98712d70 R09: 000000000000001c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: ffffffffc4653600 R14: 0000000000000001 R15: 00007f9dc6af5d1b </TASK> Modules linked in: CR2: 0000000000000000 ---[ end trace 0000000000000000 ]--- RIP: 0010:icmp6_send (net/ipv6/icmp.c:436 net/ipv6/icmp.c:503) Code: fe ff ff 48 c7 40 30 c0 86 5d 83 e8 c6 44 1c 00 e9 c8 fc ff ff 49 8b 46 58 48 83 e0 fe 0f 84 4a fb ff ff 48 8b 80 d0 00 00 00 <48> 8b 00 44 8b 88 e0 00 00 00 e9 34 fb ff ff 4d 85 ed 0f 85 69 01 RSP: 0018:ffffc90000003c70 EFLAGS: 00000286 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 00000000000000e0 RDX: 0000000000000021 RSI: 0000000000000000 RDI: ffff888006d72a18 RBP: ffffc90000003d80 R08: 0000000000000000 R09: 0000000000000001 R10: ffffc90000003d98 R11: 0000000000000040 R12: ffff888006d72a10 R13: 0000000000000000 R14: ffff8880057fb800 R15: ffffffff835d86c0 FS: 00007f9dc72ee740(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000057b2000 CR4: 00000000007506f0 PKRU: 55555554 Kernel panic - not syncing: Fatal exception in interrupt Kernel Offset: disabled Fixes: 4832c30 ("net: ipv6: put host and anycast routes on device with address") Reported-by: Wang Yufen <[email protected]> Closes: https://lore.kernel.org/netdev/[email protected]/ Signed-off-by: Kuniyuki Iwashima <[email protected]> Reviewed-by: David Ahern <[email protected]> Reviewed-by: Eric Dumazet <[email protected]> Signed-off-by: David S. Miller <[email protected]>
ojeda
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Dec 13, 2023
We should pass a pointer to global_hook to the get_proto_defrag_hook() instead of its value, since the passed value won't be updated even if the request module was loaded successfully. Log: [ 54.915713] nf_defrag_ipv4 has bad registration [ 54.915779] WARNING: CPU: 3 PID: 6323 at net/netfilter/nf_bpf_link.c:62 get_proto_defrag_hook+0x137/0x160 [ 54.915835] CPU: 3 PID: 6323 Comm: fentry Kdump: loaded Tainted: G E 6.7.0-rc2+ #35 [ 54.915839] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 [ 54.915841] RIP: 0010:get_proto_defrag_hook+0x137/0x160 [ 54.915844] Code: 4f 8c e8 2c cf 68 ff 80 3d db 83 9a 01 00 0f 85 74 ff ff ff 48 89 ee 48 c7 c7 8f 12 4f 8c c6 05 c4 83 9a 01 01 e8 09 ee 5f ff <0f> 0b e9 57 ff ff ff 49 8b 3c 24 4c 63 e5 e8 36 28 6c ff 4c 89 e0 [ 54.915849] RSP: 0018:ffffb676003fbdb0 EFLAGS: 00010286 [ 54.915852] RAX: 0000000000000023 RBX: ffff9596503d5600 RCX: ffff95996fce08c8 [ 54.915854] RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffff95996fce08c0 [ 54.915855] RBP: ffffffff8c4f12de R08: 0000000000000000 R09: 00000000fffeffff [ 54.915859] R10: ffffb676003fbc70 R11: ffffffff8d363ae8 R12: 0000000000000000 [ 54.915861] R13: ffffffff8e1f75c0 R14: ffffb676003c9000 R15: 00007ffd15e78ef0 [ 54.915864] FS: 00007fb6e9cab740(0000) GS:ffff95996fcc0000(0000) knlGS:0000000000000000 [ 54.915867] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 54.915868] CR2: 00007ffd15e75c40 CR3: 0000000101e62006 CR4: 0000000000360ef0 [ 54.915870] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 54.915871] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 54.915873] Call Trace: [ 54.915891] <TASK> [ 54.915894] ? __warn+0x84/0x140 [ 54.915905] ? get_proto_defrag_hook+0x137/0x160 [ 54.915908] ? __report_bug+0xea/0x100 [ 54.915925] ? report_bug+0x2b/0x80 [ 54.915928] ? handle_bug+0x3c/0x70 [ 54.915939] ? exc_invalid_op+0x18/0x70 [ 54.915942] ? asm_exc_invalid_op+0x1a/0x20 [ 54.915948] ? get_proto_defrag_hook+0x137/0x160 [ 54.915950] bpf_nf_link_attach+0x1eb/0x240 [ 54.915953] link_create+0x173/0x290 [ 54.915969] __sys_bpf+0x588/0x8f0 [ 54.915974] __x64_sys_bpf+0x20/0x30 [ 54.915977] do_syscall_64+0x45/0xf0 [ 54.915989] entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 54.915998] RIP: 0033:0x7fb6e9daa51d [ 54.916001] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 2b 89 0c 00 f7 d8 64 89 01 48 [ 54.916003] RSP: 002b:00007ffd15e78ed8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 [ 54.916006] RAX: ffffffffffffffda RBX: 00007ffd15e78fc0 RCX: 00007fb6e9daa51d [ 54.916007] RDX: 0000000000000040 RSI: 00007ffd15e78ef0 RDI: 000000000000001c [ 54.916009] RBP: 000000000000002d R08: 00007fb6e9e73a60 R09: 0000000000000001 [ 54.916010] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006 [ 54.916012] R13: 0000000000000006 R14: 0000000000000000 R15: 0000000000000000 [ 54.916014] </TASK> [ 54.916015] ---[ end trace 0000000000000000 ]--- Fixes: 91721c2 ("netfilter: bpf: Support BPF_F_NETFILTER_IP_DEFRAG in netfilter link") Signed-off-by: D. Wythe <[email protected]> Acked-by: Daniel Xu <[email protected]> Reviewed-by: Simon Horman <[email protected]> Signed-off-by: Pablo Neira Ayuso <[email protected]>
ojeda
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Dec 13, 2023
The `cgrp_local_storage` test triggers a kernel panic like: # ./test_progs -t cgrp_local_storage Can't find bpf_testmod.ko kernel module: -2 WARNING! Selftests relying on bpf_testmod.ko will be skipped. [ 550.930632] CPU 1 Unable to handle kernel paging request at virtual address 0000000000000080, era == ffff80000200be34, ra == ffff80000200be00 [ 550.931781] Oops[#1]: [ 550.931966] CPU: 1 PID: 1303 Comm: test_progs Not tainted 6.7.0-rc2-loong-devel-g2f56bb0d2327 #35 a896aca3f4164f09cc346f89f2e09832e07be5f6 [ 550.932215] Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 2/2/2022 [ 550.932403] pc ffff80000200be34 ra ffff80000200be00 tp 9000000108350000 sp 9000000108353dc0 [ 550.932545] a0 0000000000000000 a1 0000000000000517 a2 0000000000000118 a3 00007ffffbb15558 [ 550.932682] a4 00007ffffbb15620 a5 90000001004e7700 a6 0000000000000021 a7 0000000000000118 [ 550.932824] t0 ffff80000200bdc0 t1 0000000000000517 t2 0000000000000517 t3 00007ffff1c06ee0 [ 550.932961] t4 0000555578ae04d0 t5 fffffffffffffff8 t6 0000000000000004 t7 0000000000000020 [ 550.933097] t8 0000000000000040 u0 00000000000007b8 s9 9000000108353e00 s0 90000001004e7700 [ 550.933241] s1 9000000004005000 s2 0000000000000001 s3 0000000000000000 s4 0000555555eb2ec8 [ 550.933379] s5 00007ffffbb15bb8 s6 00007ffff1dafd60 s7 000055555663f610 s8 00007ffff1db0050 [ 550.933520] ra: ffff80000200be00 bpf_prog_98f1b9e767be2a84_on_enter+0x40/0x200 [ 550.933911] ERA: ffff80000200be34 bpf_prog_98f1b9e767be2a84_on_enter+0x74/0x200 [ 550.934105] CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE) [ 550.934596] PRMD: 00000004 (PPLV0 +PIE -PWE) [ 550.934712] EUEN: 00000003 (+FPE +SXE -ASXE -BTE) [ 550.934836] ECFG: 00071c1c (LIE=2-4,10-12 VS=7) [ 550.934976] ESTAT: 00010000 [PIL] (IS= ECode=1 EsubCode=0) [ 550.935097] BADV: 0000000000000080 [ 550.935181] PRID: 0014c010 (Loongson-64bit, Loongson-3A5000) [ 550.935291] Modules linked in: [ 550.935391] Process test_progs (pid: 1303, threadinfo=000000006c3b1c41, task=0000000061f84a55) [ 550.935643] Stack : 00007ffffbb15bb8 0000555555eb2ec8 0000000000000000 0000000000000001 [ 550.935844] 9000000004005000 ffff80001b864000 00007ffffbb15450 90000000029aa034 [ 550.935990] 0000000000000000 9000000108353ec0 0000000000000118 d07d9dfb09721a09 [ 550.936175] 0000000000000001 0000000000000000 9000000108353ec0 0000000000000118 [ 550.936314] 9000000101d46ad0 900000000290abf0 000055555663f610 0000000000000000 [ 550.936479] 0000000000000003 9000000108353ec0 00007ffffbb15450 90000000029d7288 [ 550.936635] 00007ffff1dafd60 000055555663f610 0000000000000000 0000000000000003 [ 550.936779] 9000000108353ec0 90000000035dd1f0 00007ffff1dafd58 9000000002841c5c [ 550.936939] 0000000000000119 0000555555eea5a8 00007ffff1d78780 00007ffffbb153e0 [ 550.937083] ffffffffffffffda 00007ffffbb15518 0000000000000040 00007ffffbb15558 [ 550.937224] ... [ 550.937299] Call Trace: [ 550.937521] [<ffff80000200be34>] bpf_prog_98f1b9e767be2a84_on_enter+0x74/0x200 [ 550.937910] [<90000000029aa034>] bpf_trace_run2+0x90/0x154 [ 550.938105] [<900000000290abf0>] syscall_trace_enter.isra.0+0x1cc/0x200 [ 550.938224] [<90000000035dd1f0>] do_syscall+0x48/0x94 [ 550.938319] [<9000000002841c5c>] handle_syscall+0xbc/0x158 [ 550.938477] [ 550.938607] Code: 580009ae 50016000 262402e4 <28c20085> 14092084 03a00084 16000024 03240084 00150006 [ 550.938851] [ 550.939021] ---[ end trace 0000000000000000 ]--- Further investigation shows that this panic is triggered by memory load operations: ptr = bpf_cgrp_storage_get(&map_a, task->cgroups->dfl_cgrp, 0, BPF_LOCAL_STORAGE_GET_F_CREATE); The expression `task->cgroups->dfl_cgrp` involves two memory load. Since the field offset fits in imm12 or imm14, we use ldd or ldptrd instructions. But both instructions have the side effect that it will signed-extended the imm operand. Finally, we got the wrong addresses and panics is inevitable. Use a generic ldxd instruction to avoid this kind of issues. With this change, we have: # ./test_progs -t cgrp_local_storage Can't find bpf_testmod.ko kernel module: -2 WARNING! Selftests relying on bpf_testmod.ko will be skipped. test_cgrp_local_storage:PASS:join_cgroup /cgrp_local_storage 0 nsec #48/1 cgrp_local_storage/tp_btf:OK test_attach_cgroup:PASS:skel_open 0 nsec test_attach_cgroup:PASS:prog_attach 0 nsec test_attach_cgroup:PASS:prog_attach 0 nsec libbpf: prog 'update_cookie_tracing': failed to attach: ERROR: strerror_r(-524)=22 test_attach_cgroup:FAIL:prog_attach unexpected error: -524 #48/2 cgrp_local_storage/attach_cgroup:FAIL test_recursion:PASS:skel_open_and_load 0 nsec libbpf: prog 'on_lookup': failed to attach: ERROR: strerror_r(-524)=22 libbpf: prog 'on_lookup': failed to auto-attach: -524 test_recursion:FAIL:skel_attach unexpected error: -524 (errno 524) #48/3 cgrp_local_storage/recursion:FAIL #48/4 cgrp_local_storage/negative:OK #48/5 cgrp_local_storage/cgroup_iter_sleepable:OK test_yes_rcu_lock:PASS:skel_open 0 nsec test_yes_rcu_lock:PASS:skel_load 0 nsec libbpf: prog 'yes_rcu_lock': failed to attach: ERROR: strerror_r(-524)=22 libbpf: prog 'yes_rcu_lock': failed to auto-attach: -524 test_yes_rcu_lock:FAIL:skel_attach unexpected error: -524 (errno 524) #48/6 cgrp_local_storage/yes_rcu_lock:FAIL #48/7 cgrp_local_storage/no_rcu_lock:OK #48 cgrp_local_storage:FAIL All error logs: test_cgrp_local_storage:PASS:join_cgroup /cgrp_local_storage 0 nsec test_attach_cgroup:PASS:skel_open 0 nsec test_attach_cgroup:PASS:prog_attach 0 nsec test_attach_cgroup:PASS:prog_attach 0 nsec libbpf: prog 'update_cookie_tracing': failed to attach: ERROR: strerror_r(-524)=22 test_attach_cgroup:FAIL:prog_attach unexpected error: -524 #48/2 cgrp_local_storage/attach_cgroup:FAIL test_recursion:PASS:skel_open_and_load 0 nsec libbpf: prog 'on_lookup': failed to attach: ERROR: strerror_r(-524)=22 libbpf: prog 'on_lookup': failed to auto-attach: -524 test_recursion:FAIL:skel_attach unexpected error: -524 (errno 524) #48/3 cgrp_local_storage/recursion:FAIL test_yes_rcu_lock:PASS:skel_open 0 nsec test_yes_rcu_lock:PASS:skel_load 0 nsec libbpf: prog 'yes_rcu_lock': failed to attach: ERROR: strerror_r(-524)=22 libbpf: prog 'yes_rcu_lock': failed to auto-attach: -524 test_yes_rcu_lock:FAIL:skel_attach unexpected error: -524 (errno 524) #48/6 cgrp_local_storage/yes_rcu_lock:FAIL #48 cgrp_local_storage:FAIL Summary: 0/4 PASSED, 0 SKIPPED, 1 FAILED No panics any more (The test still failed because lack of BPF trampoline which I am actively working on). Fixes: 5dc6155 ("LoongArch: Add BPF JIT support") Signed-off-by: Hengqi Chen <[email protected]> Signed-off-by: Huacai Chen <[email protected]>
ojeda
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that referenced
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Dec 13, 2023
The `cls_redirect` test triggers a kernel panic like: # ./test_progs -t cls_redirect Can't find bpf_testmod.ko kernel module: -2 WARNING! Selftests relying on bpf_testmod.ko will be skipped. [ 30.938489] CPU 3 Unable to handle kernel paging request at virtual address fffffffffd814de0, era == ffff800002009fb8, ra == ffff800002009f9c [ 30.939331] Oops[#1]: [ 30.939513] CPU: 3 PID: 1260 Comm: test_progs Not tainted 6.7.0-rc2-loong-devel-g2f56bb0d2327 #35 a896aca3f4164f09cc346f89f2e09832e07be5f6 [ 30.939732] Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 2/2/2022 [ 30.939901] pc ffff800002009fb8 ra ffff800002009f9c tp 9000000104da4000 sp 9000000104da7ab0 [ 30.940038] a0 fffffffffd814de0 a1 9000000104da7a68 a2 0000000000000000 a3 9000000104da7c10 [ 30.940183] a4 9000000104da7c14 a5 0000000000000002 a6 0000000000000021 a7 00005555904d7f90 [ 30.940321] t0 0000000000000110 t1 0000000000000000 t2 fffffffffd814de0 t3 0004c4b400000000 [ 30.940456] t4 ffffffffffffffff t5 00000000c3f63600 t6 0000000000000000 t7 0000000000000000 [ 30.940590] t8 000000000006d803 u0 0000000000000020 s9 9000000104da7b10 s0 900000010504c200 [ 30.940727] s1 fffffffffd814de0 s2 900000010504c200 s3 9000000104da7c10 s4 9000000104da7ad0 [ 30.940866] s5 0000000000000000 s6 90000000030e65bc s7 9000000104da7b44 s8 90000000044f6fc0 [ 30.941015] ra: ffff800002009f9c bpf_prog_846803e5ae81417f_cls_redirect+0xa0/0x590 [ 30.941535] ERA: ffff800002009fb8 bpf_prog_846803e5ae81417f_cls_redirect+0xbc/0x590 [ 30.941696] CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE) [ 30.942224] PRMD: 00000004 (PPLV0 +PIE -PWE) [ 30.942330] EUEN: 00000003 (+FPE +SXE -ASXE -BTE) [ 30.942453] ECFG: 00071c1c (LIE=2-4,10-12 VS=7) [ 30.942612] ESTAT: 00010000 [PIL] (IS= ECode=1 EsubCode=0) [ 30.942764] BADV: fffffffffd814de0 [ 30.942854] PRID: 0014c010 (Loongson-64bit, Loongson-3A5000) [ 30.942974] Modules linked in: [ 30.943078] Process test_progs (pid: 1260, threadinfo=00000000ce303226, task=000000007d10bb76) [ 30.943306] Stack : 900000010a064000 90000000044f6fc0 9000000104da7b48 0000000000000000 [ 30.943495] 0000000000000000 9000000104da7c14 9000000104da7c10 900000010504c200 [ 30.943626] 0000000000000001 ffff80001b88c000 9000000104da7b70 90000000030e6668 [ 30.943785] 0000000000000000 9000000104da7b58 ffff80001b88c048 9000000003d05000 [ 30.943936] 900000000303ac88 0000000000000000 0000000000000000 9000000104da7b70 [ 30.944091] 0000000000000000 0000000000000001 0000000731eeab00 0000000000000000 [ 30.944245] ffff80001b88c000 0000000000000000 0000000000000000 54b99959429f83b8 [ 30.944402] ffff80001b88c000 90000000044f6fc0 9000000101d70000 ffff80001b88c000 [ 30.944538] 000000000000005a 900000010504c200 900000010a064000 900000010a067000 [ 30.944697] 9000000104da7d88 0000000000000000 9000000003d05000 90000000030e794c [ 30.944852] ... [ 30.944924] Call Trace: [ 30.945120] [<ffff800002009fb8>] bpf_prog_846803e5ae81417f_cls_redirect+0xbc/0x590 [ 30.945650] [<90000000030e6668>] bpf_test_run+0x1ec/0x2f8 [ 30.945958] [<90000000030e794c>] bpf_prog_test_run_skb+0x31c/0x684 [ 30.946065] [<90000000026d4f68>] __sys_bpf+0x678/0x2724 [ 30.946159] [<90000000026d7288>] sys_bpf+0x20/0x2c [ 30.946253] [<90000000032dd224>] do_syscall+0x7c/0x94 [ 30.946343] [<9000000002541c5c>] handle_syscall+0xbc/0x158 [ 30.946492] [ 30.946549] Code: 0015030e 5c0009c0 5001d000 <28c00304> 02c00484 29c00304 00150009 2a42d2e4 0280200d [ 30.946793] [ 30.946971] ---[ end trace 0000000000000000 ]--- [ 32.093225] Kernel panic - not syncing: Fatal exception in interrupt [ 32.093526] Kernel relocated by 0x2320000 [ 32.093630] .text @ 0x9000000002520000 [ 32.093725] .data @ 0x9000000003400000 [ 32.093792] .bss @ 0x9000000004413200 [ 34.971998] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]--- This is because we signed-extend function return values. When subprog mode is enabled, we have: cls_redirect() -> get_global_metrics() returns pcpu ptr 0xfffffefffc00b480 The pointer returned is later signed-extended to 0xfffffffffc00b480 at `BPF_JMP | BPF_EXIT`. During BPF prog run, this triggers unhandled page fault and a kernel panic. Drop the unnecessary signed-extension on return values like other architectures do. With this change, we have: # ./test_progs -t cls_redirect Can't find bpf_testmod.ko kernel module: -2 WARNING! Selftests relying on bpf_testmod.ko will be skipped. #51/1 cls_redirect/cls_redirect_inlined:OK #51/2 cls_redirect/IPv4 TCP accept unknown (no hops, flags: SYN):OK #51/3 cls_redirect/IPv6 TCP accept unknown (no hops, flags: SYN):OK #51/4 cls_redirect/IPv4 TCP accept unknown (no hops, flags: ACK):OK #51/5 cls_redirect/IPv6 TCP accept unknown (no hops, flags: ACK):OK #51/6 cls_redirect/IPv4 TCP forward unknown (one hop, flags: ACK):OK #51/7 cls_redirect/IPv6 TCP forward unknown (one hop, flags: ACK):OK #51/8 cls_redirect/IPv4 TCP accept known (one hop, flags: ACK):OK #51/9 cls_redirect/IPv6 TCP accept known (one hop, flags: ACK):OK #51/10 cls_redirect/IPv4 UDP accept unknown (no hops, flags: none):OK #51/11 cls_redirect/IPv6 UDP accept unknown (no hops, flags: none):OK #51/12 cls_redirect/IPv4 UDP forward unknown (one hop, flags: none):OK #51/13 cls_redirect/IPv6 UDP forward unknown (one hop, flags: none):OK #51/14 cls_redirect/IPv4 UDP accept known (one hop, flags: none):OK #51/15 cls_redirect/IPv6 UDP accept known (one hop, flags: none):OK #51/16 cls_redirect/cls_redirect_subprogs:OK #51/17 cls_redirect/IPv4 TCP accept unknown (no hops, flags: SYN):OK #51/18 cls_redirect/IPv6 TCP accept unknown (no hops, flags: SYN):OK #51/19 cls_redirect/IPv4 TCP accept unknown (no hops, flags: ACK):OK #51/20 cls_redirect/IPv6 TCP accept unknown (no hops, flags: ACK):OK #51/21 cls_redirect/IPv4 TCP forward unknown (one hop, flags: ACK):OK #51/22 cls_redirect/IPv6 TCP forward unknown (one hop, flags: ACK):OK #51/23 cls_redirect/IPv4 TCP accept known (one hop, flags: ACK):OK #51/24 cls_redirect/IPv6 TCP accept known (one hop, flags: ACK):OK #51/25 cls_redirect/IPv4 UDP accept unknown (no hops, flags: none):OK #51/26 cls_redirect/IPv6 UDP accept unknown (no hops, flags: none):OK #51/27 cls_redirect/IPv4 UDP forward unknown (one hop, flags: none):OK #51/28 cls_redirect/IPv6 UDP forward unknown (one hop, flags: none):OK #51/29 cls_redirect/IPv4 UDP accept known (one hop, flags: none):OK #51/30 cls_redirect/IPv6 UDP accept known (one hop, flags: none):OK #51/31 cls_redirect/cls_redirect_dynptr:OK #51/32 cls_redirect/IPv4 TCP accept unknown (no hops, flags: SYN):OK #51/33 cls_redirect/IPv6 TCP accept unknown (no hops, flags: SYN):OK #51/34 cls_redirect/IPv4 TCP accept unknown (no hops, flags: ACK):OK #51/35 cls_redirect/IPv6 TCP accept unknown (no hops, flags: ACK):OK #51/36 cls_redirect/IPv4 TCP forward unknown (one hop, flags: ACK):OK #51/37 cls_redirect/IPv6 TCP forward unknown (one hop, flags: ACK):OK #51/38 cls_redirect/IPv4 TCP accept known (one hop, flags: ACK):OK #51/39 cls_redirect/IPv6 TCP accept known (one hop, flags: ACK):OK #51/40 cls_redirect/IPv4 UDP accept unknown (no hops, flags: none):OK #51/41 cls_redirect/IPv6 UDP accept unknown (no hops, flags: none):OK #51/42 cls_redirect/IPv4 UDP forward unknown (one hop, flags: none):OK #51/43 cls_redirect/IPv6 UDP forward unknown (one hop, flags: none):OK #51/44 cls_redirect/IPv4 UDP accept known (one hop, flags: none):OK #51/45 cls_redirect/IPv6 UDP accept known (one hop, flags: none):OK #51 cls_redirect:OK Summary: 1/45 PASSED, 0 SKIPPED, 0 FAILED Fixes: 5dc6155 ("LoongArch: Add BPF JIT support") Signed-off-by: Hengqi Chen <[email protected]> Signed-off-by: Huacai Chen <[email protected]>
fbq
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Dec 28, 2023
When we are slave role and receives l2cap conn req when encryption has
started, we should check the enc key size to avoid KNOB attack or BLUFFS
attack.
From SIG recommendation, implementations are advised to reject
service-level connections on an encrypted baseband link with key
strengths below 7 octets.
A simple and clear way to achieve this is to place the enc key size
check in hci_cc_read_enc_key_size()
The btmon log below shows the case that lacks enc key size check.
> HCI Event: Connect Request (0x04) plen 10
Address: BB:22:33:44:55:99 (OUI BB-22-33)
Class: 0x480104
Major class: Computer (desktop, notebook, PDA, organizers)
Minor class: Desktop workstation
Capturing (Scanner, Microphone)
Telephony (Cordless telephony, Modem, Headset)
Link type: ACL (0x01)
< HCI Command: Accept Connection Request (0x01|0x0009) plen 7
Address: BB:22:33:44:55:99 (OUI BB-22-33)
Role: Peripheral (0x01)
> HCI Event: Command Status (0x0f) plen 4
Accept Connection Request (0x01|0x0009) ncmd 2
Status: Success (0x00)
> HCI Event: Connect Complete (0x03) plen 11
Status: Success (0x00)
Handle: 1
Address: BB:22:33:44:55:99 (OUI BB-22-33)
Link type: ACL (0x01)
Encryption: Disabled (0x00)
...
> HCI Event: Encryption Change (0x08) plen 4
Status: Success (0x00)
Handle: 1 Address: BB:22:33:44:55:99 (OUI BB-22-33)
Encryption: Enabled with E0 (0x01)
< HCI Command: Read Encryption Key Size (0x05|0x0008) plen 2
Handle: 1 Address: BB:22:33:44:55:99 (OUI BB-22-33)
> HCI Event: Command Complete (0x0e) plen 7
Read Encryption Key Size (0x05|0x0008) ncmd 2
Status: Success (0x00)
Handle: 1 Address: BB:22:33:44:55:99 (OUI BB-22-33)
Key size: 6
// We should check the enc key size
...
> ACL Data RX: Handle 1 flags 0x02 dlen 12
L2CAP: Connection Request (0x02) ident 3 len 4
PSM: 25 (0x0019)
Source CID: 64
< ACL Data TX: Handle 1 flags 0x00 dlen 16
L2CAP: Connection Response (0x03) ident 3 len 8
Destination CID: 64
Source CID: 64
Result: Connection pending (0x0001)
Status: Authorization pending (0x0002)
> HCI Event: Number of Completed Packets (0x13) plen 5
Num handles: 1
Handle: 1 Address: BB:22:33:44:55:99 (OUI BB-22-33)
Count: 1
#35: len 16 (25 Kb/s)
Latency: 5 msec (2-7 msec ~4 msec)
< ACL Data TX: Handle 1 flags 0x00 dlen 16
L2CAP: Connection Response (0x03) ident 3 len 8
Destination CID: 64
Source CID: 64
Result: Connection successful (0x0000)
Status: No further information available (0x0000)
Cc: [email protected]
Signed-off-by: Alex Lu <[email protected]>
Signed-off-by: Max Chou <[email protected]>
Signed-off-by: Luiz Augusto von Dentz <[email protected]>
ojeda
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Aug 18, 2024
Ignore the userspace provided x2APIC ID when fixing up APIC state for KVM_SET_LAPIC, i.e. make the x2APIC fully readonly in KVM. Commit a92e254 ("KVM: x86: use hardware-compatible format for APIC ID register"), which added the fixup, didn't intend to allow userspace to modify the x2APIC ID. In fact, that commit is when KVM first started treating the x2APIC ID as readonly, apparently to fix some race: static inline u32 kvm_apic_id(struct kvm_lapic *apic) { - return (kvm_lapic_get_reg(apic, APIC_ID) >> 24) & 0xff; + /* To avoid a race between apic_base and following APIC_ID update when + * switching to x2apic_mode, the x2apic mode returns initial x2apic id. + */ + if (apic_x2apic_mode(apic)) + return apic->vcpu->vcpu_id; + + return kvm_lapic_get_reg(apic, APIC_ID) >> 24; } Furthermore, KVM doesn't support delivering interrupts to vCPUs with a modified x2APIC ID, but KVM *does* return the modified value on a guest RDMSR and for KVM_GET_LAPIC. I.e. no remotely sane setup can actually work with a modified x2APIC ID. Making the x2APIC ID fully readonly fixes a WARN in KVM's optimized map calculation, which expects the LDR to align with the x2APIC ID. WARNING: CPU: 2 PID: 958 at arch/x86/kvm/lapic.c:331 kvm_recalculate_apic_map+0x609/0xa00 [kvm] CPU: 2 PID: 958 Comm: recalc_apic_map Not tainted 6.4.0-rc3-vanilla+ #35 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.2-1-1 04/01/2014 RIP: 0010:kvm_recalculate_apic_map+0x609/0xa00 [kvm] Call Trace: <TASK> kvm_apic_set_state+0x1cf/0x5b0 [kvm] kvm_arch_vcpu_ioctl+0x1806/0x2100 [kvm] kvm_vcpu_ioctl+0x663/0x8a0 [kvm] __x64_sys_ioctl+0xb8/0xf0 do_syscall_64+0x56/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7fade8b9dd6f Unfortunately, the WARN can still trigger for other CPUs than the current one by racing against KVM_SET_LAPIC, so remove it completely. Reported-by: Michal Luczaj <[email protected]> Closes: https://lore.kernel.org/all/[email protected] Reported-by: Haoyu Wu <[email protected]> Closes: https://lore.kernel.org/all/[email protected] Reported-by: [email protected] Closes: https://lore.kernel.org/all/[email protected] Signed-off-by: Sean Christopherson <[email protected]> Message-ID: <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
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