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authorJackie Liu <liuyun01@kylinos.cn>2019-07-08 13:41:12 +0800
committerJens Axboe <axboe@kernel.dk>2019-07-09 14:32:05 -0600
commita4c0b3decb33fb4a2b5ecc6234a50680f0b21e7d (patch)
tree98020ae66753d99bdb1cbe110364a20b824e3aa6 /drivers/input/joydev.c
parentio_uring: add support for recvmsg() (diff)
downloadlinux-dev-a4c0b3decb33fb4a2b5ecc6234a50680f0b21e7d.tar.xz
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io_uring: fix io_sq_thread_stop running in front of io_sq_thread
INFO: task syz-executor.5:8634 blocked for more than 143 seconds. Not tainted 5.2.0-rc5+ #3 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D25632 8634 8224 0x00004004 Call Trace: context_switch kernel/sched/core.c:2818 [inline] __schedule+0x658/0x9e0 kernel/sched/core.c:3445 schedule+0x131/0x1d0 kernel/sched/core.c:3509 schedule_timeout+0x9a/0x2b0 kernel/time/timer.c:1783 do_wait_for_common+0x35e/0x5a0 kernel/sched/completion.c:83 __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x47/0x60 kernel/sched/completion.c:136 kthread_stop+0xb4/0x150 kernel/kthread.c:559 io_sq_thread_stop fs/io_uring.c:2252 [inline] io_finish_async fs/io_uring.c:2259 [inline] io_ring_ctx_free fs/io_uring.c:2770 [inline] io_ring_ctx_wait_and_kill+0x268/0x880 fs/io_uring.c:2834 io_uring_release+0x5d/0x70 fs/io_uring.c:2842 __fput+0x2e4/0x740 fs/file_table.c:280 ____fput+0x15/0x20 fs/file_table.c:313 task_work_run+0x17e/0x1b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:185 [inline] exit_to_usermode_loop arch/x86/entry/common.c:168 [inline] prepare_exit_to_usermode+0x402/0x4f0 arch/x86/entry/common.c:199 syscall_return_slowpath+0x110/0x440 arch/x86/entry/common.c:279 do_syscall_64+0x126/0x140 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x412fb1 Code: 80 3b 7c 0f 84 c7 02 00 00 c7 85 d0 00 00 00 00 00 00 00 48 8b 05 cf a6 24 00 49 8b 14 24 41 b9 cb 2a 44 00 48 89 ee 48 89 df <48> 85 c0 4c 0f 45 c8 45 31 c0 31 c9 e8 0e 5b 00 00 85 c0 41 89 c7 RSP: 002b:00007ffe7ee6a180 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000412fb1 RDX: 0000001b2d920000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00000000f3a3e1f8 R09: 00000000f3a3e1fc R10: 00007ffe7ee6a260 R11: 0000000000000293 R12: 000000000075c9a0 R13: 000000000075c9a0 R14: 0000000000024c00 R15: 000000000075bf2c ============================================= There is an wrong logic, when kthread_park running in front of io_sq_thread. CPU#0 CPU#1 io_sq_thread_stop: int kthread(void *_create): kthread_park() __kthread_parkme(self); <<< Wrong kthread_stop() << wait for self->exited << clear_bit KTHREAD_SHOULD_PARK ret = threadfn(data); | |- io_sq_thread |- kthread_should_park() << false |- schedule() <<< nobody wake up stuck CPU#0 stuck CPU#1 So, use a new variable sqo_thread_started to ensure that io_sq_thread run first, then io_sq_thread_stop. Reported-by: syzbot+94324416c485d422fe15@syzkaller.appspotmail.com Suggested-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jackie Liu <liuyun01@kylinos.cn> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/input/joydev.c')
0 files changed, 0 insertions, 0 deletions