From 6b393a1ff1746a1c91bd95cbb2d79b104d8f15ac Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Sat, 16 Jan 2021 05:32:29 +0000 Subject: io_uring: fix false positive sqo warning on flush WARNING: CPU: 1 PID: 9094 at fs/io_uring.c:8884 io_disable_sqo_submit+0x106/0x130 fs/io_uring.c:8884 Call Trace: io_uring_flush+0x28b/0x3a0 fs/io_uring.c:9099 filp_close+0xb4/0x170 fs/open.c:1280 close_fd+0x5c/0x80 fs/file.c:626 __do_sys_close fs/open.c:1299 [inline] __se_sys_close fs/open.c:1297 [inline] __x64_sys_close+0x2f/0xa0 fs/open.c:1297 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 io_uring's final close() may be triggered by any task not only the creator. It's well handled by io_uring_flush() including SQPOLL case, though a warning in io_disable_sqo_submit() will fallaciously fire by moving this warning out to the only call site that matters. Reported-by: syzbot+2f5d1785dc624932da78@syzkaller.appspotmail.com Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- fs/io_uring.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/io_uring.c b/fs/io_uring.c index 5cda878b69cf..616c5f732a26 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -8918,8 +8918,6 @@ static void __io_uring_cancel_task_requests(struct io_ring_ctx *ctx, static void io_disable_sqo_submit(struct io_ring_ctx *ctx) { - WARN_ON_ONCE(ctx->sqo_task != current); - mutex_lock(&ctx->uring_lock); ctx->sqo_dead = 1; mutex_unlock(&ctx->uring_lock); @@ -8941,6 +8939,7 @@ static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx, if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) { /* for SQPOLL only sqo_task has task notes */ + WARN_ON_ONCE(ctx->sqo_task != current); io_disable_sqo_submit(ctx); task = ctx->sq_data->thread; atomic_inc(&task->io_uring->in_idle); -- cgit v1.2.3