linux-kernel - [PATCH 5.10 08/54] io_uring: if we see flush on exit, cancel related tasks

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Date:   Thu, 11 Feb 2021 16:01:52 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Josef Grieb <josef.grieb@...il.com>,
        Jens Axboe <axboe@...nel.dk>,
        Pavel Begunkov <asml.silence@...il.com>
Subject: [PATCH 5.10 08/54] io_uring: if we see flush on exit, cancel related tasks

From: Jens Axboe <axboe@...nel.dk>

[ Upstream commit 84965ff8a84f0368b154c9b367b62e59c1193f30 ]

Ensure we match tasks that belong to a dead or dying task as well, as we
need to reap those in addition to those belonging to the exiting task.

Cc: stable@...r.kernel.org # 5.9+
Reported-by: Josef Grieb <josef.grieb@...il.com>
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@...il.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/io_uring.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1014,8 +1014,12 @@ static bool io_match_task(struct io_kioc
 {
 	struct io_kiocb *link;
 
-	if (task && head->task != task)
+	if (task && head->task != task) {
+		/* in terms of cancelation, always match if req task is dead */
+		if (head->task->flags & PF_EXITING)
+			return true;
 		return false;
+	}
 	if (!files)
 		return true;
 	if (__io_match_files(head, files))
@@ -8844,6 +8848,9 @@ static int io_uring_flush(struct file *f
 	struct io_uring_task *tctx = current->io_uring;
 	struct io_ring_ctx *ctx = file->private_data;
 
+	if (fatal_signal_pending(current) || (current->flags & PF_EXITING))
+		io_uring_cancel_task_requests(ctx, NULL);
+
 	if (!tctx)
 		return 0;