From c7d95613c7d6e003969722a290397b8271bdad17 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Tue, 13 Apr 2021 11:43:00 +0100 Subject: io_uring: fix early sqd_list removal sqpoll hangs [ 245.463317] INFO: task iou-sqp-1374:1377 blocked for more than 122 seconds. [ 245.463334] task:iou-sqp-1374 state:D flags:0x00004000 [ 245.463345] Call Trace: [ 245.463352] __schedule+0x36b/0x950 [ 245.463376] schedule+0x68/0xe0 [ 245.463385] __io_uring_cancel+0xfb/0x1a0 [ 245.463407] do_exit+0xc0/0xb40 [ 245.463423] io_sq_thread+0x49b/0x710 [ 245.463445] ret_from_fork+0x22/0x30 It happens when sqpoll forgot to run park_task_work and goes to exit, then exiting user may remove ctx from sqd_list, and so corresponding io_sq_thread() -> io_uring_cancel_sqpoll() won't be executed. Hopefully it just stucks in do_exit() in this case. Fixes: dbe1bdbb39db ("io_uring: handle signals for IO threads like a normal thread") Reported-by: Joakim Hassila Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- fs/io_uring.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'fs/io_uring.c') diff --git a/fs/io_uring.c b/fs/io_uring.c index bd14327c8e7e..dff34975d86b 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -6754,6 +6754,9 @@ static int io_sq_thread(void *data) current->flags |= PF_NO_SETAFFINITY; mutex_lock(&sqd->lock); + /* a user may had exited before the thread started */ + io_run_task_work_head(&sqd->park_task_work); + while (!test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state)) { int ret; bool cap_entries, sqt_spin, needs_sched; @@ -6770,10 +6773,10 @@ static int io_sq_thread(void *data) } cond_resched(); mutex_lock(&sqd->lock); - if (did_sig) - break; io_run_task_work(); io_run_task_work_head(&sqd->park_task_work); + if (did_sig) + break; timeout = jiffies + sqd->sq_thread_idle; continue; } -- cgit v1.2.3-59-g8ed1b