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From: Pavel Begunkov <[email protected]>
To: Jens Axboe <[email protected]>, [email protected]
Cc: [email protected],
	[email protected]
Subject: [PATCH 2/2] io_uring: fix sqo ownership false positive warning
Date: Thu, 28 Jan 2021 18:39:25 +0000	[thread overview]
Message-ID: <4864e44e886a651f87288ad9a0ffdeea4ac025a7.1611859042.git.asml.silence@gmail.com> (raw)
In-Reply-To: <[email protected]>

WARNING: CPU: 0 PID: 21359 at fs/io_uring.c:9042
    io_uring_cancel_task_requests+0xe55/0x10c0 fs/io_uring.c:9042
Call Trace:
 io_uring_flush+0x47b/0x6e0 fs/io_uring.c:9227
 filp_close+0xb4/0x170 fs/open.c:1295
 close_files fs/file.c:403 [inline]
 put_files_struct fs/file.c:418 [inline]
 put_files_struct+0x1cc/0x350 fs/file.c:415
 exit_files+0x7e/0xa0 fs/file.c:435
 do_exit+0xc22/0x2ae0 kernel/exit.c:820
 do_group_exit+0x125/0x310 kernel/exit.c:922
 get_signal+0x427/0x20f0 kernel/signal.c:2773
 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:811
 handle_signal_work kernel/entry/common.c:147 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x148/0x250 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Now io_uring_cancel_task_requests() can be called not through file
notes but directly, remove a WARN_ONCE() there that give us false
positives. That check is not very important and we catch it in other
places.

Fixes: 84965ff8a84f0 ("io_uring: if we see flush on exit, cancel related tasks")
Cc: [email protected] # 5.9+
Reported-by: [email protected]
Signed-off-by: Pavel Begunkov <[email protected]>
---
 fs/io_uring.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 39ae1f821cef..12bf7180c0f1 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8967,8 +8967,6 @@ static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
 	struct task_struct *task = current;
 
 	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);
-- 
2.24.0


      parent reply	other threads:[~2021-01-28 18:46 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-28 18:39 [PATCH 0/2] io_uring-file req cancel syzbot reports Pavel Begunkov
2021-01-28 18:39 ` [PATCH 1/2] io_uring: fix list corruption for splice file_get Pavel Begunkov
2021-01-28 18:39 ` Pavel Begunkov [this message]

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