The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 70b2c60d3797bffe182dddb9bb55975b9be5889a Mon Sep 17 00:00:00 2001
From: Pavel Begunkov asml.silence@gmail.com Date: Thu, 28 Jan 2021 18:39:25 +0000 Subject: [PATCH] io_uring: fix sqo ownership false positive warning
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: stable@vger.kernel.org # 5.9+ Reported-by: syzbot+3e3d9bd0c6ce9efbc3ef@syzkaller.appspotmail.com Signed-off-by: Pavel Begunkov asml.silence@gmail.com Signed-off-by: Jens Axboe axboe@kernel.dk
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);