Don't set IO_SQ_THREAD_SHOULD_STOP when io_sq_offload_create() has failed on io_uring_alloc_task_context() but leave everything to io_sq_thread_finish(), because currently io_sq_thread_finish() hangs on trying to park it. That's great it stalls there, because otherwise the following io_sq_thread_stop() would be skipped on IO_SQ_THREAD_SHOULD_STOP check and the sqo would race for sqd with freeing ctx. A simple error injection gives something like this. [ 245.463955] INFO: task sqpoll-test-hang:523 blocked for more than 122 seconds. [ 245.463983] Call Trace: [ 245.463990] __schedule+0x36b/0x950 [ 245.464005] schedule+0x68/0xe0 [ 245.464013] schedule_timeout+0x209/0x2a0 [ 245.464032] wait_for_completion+0x8b/0xf0 [ 245.464043] io_sq_thread_finish+0x44/0x1a0 [ 245.464049] io_uring_setup+0x9ea/0xc80 [ 245.464058] __x64_sys_io_uring_setup+0x16/0x20 [ 245.464064] do_syscall_64+0x38/0x50 [ 245.464073] entry_SYSCALL_64_after_hwframe+0x44/0xae Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx> --- fs/io_uring.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 5505e19f1391..5ca3c70e6640 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -7860,10 +7860,9 @@ static int io_sq_offload_create(struct io_ring_ctx *ctx, ret = PTR_ERR(tsk); goto err; } - ret = io_uring_alloc_task_context(tsk, ctx); - if (ret) - set_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state); + sqd->thread = tsk; + ret = io_uring_alloc_task_context(tsk, ctx); wake_up_new_task(tsk); if (ret) goto err; -- 2.24.0
