On 7/8/19 6:37 PM, JackieLiu wrote: > > >> 在 2019年7月9日，06:31，Jens Axboe <axboe@xxxxxxxxx> 写道： >> >> On 7/7/19 11:41 PM, Jackie Liu wrote: >>> 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. >> >> I think this looks fine now, I'll apply it. Thanks! >> >> Do you have the test case as well? Would like to add it to the >> liburing arsenal of regression tests. > > Yes, I will. but what's the rules for naming file, they look like sha1 > or MD5 values. It's the git sha of the commit that fixed the problem. But don't worry about that, call it whatever and I'll fix it up, if need be. -- Jens Axboe
