linux-kernel - [PATCH] exec: Move io_uring_task_cancel after the point of no return

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Message-ID: <878saih2op.fsf@x220.int.ebiederm.org>
Date:   Mon, 30 Nov 2020 16:58:46 -0600
From:   ebiederm@...ssion.com (Eric W. Biederman)
To:     <linux-kernel@...r.kernel.org>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Oleg Nesterov <oleg@...hat.com>,
        Al Viro <viro@...IV.linux.org.uk>,
        Kees Cook <keescook@...omium.org>, Jens Axboe <axboe@...nel.dk>
Subject: [PATCH] exec: Move io_uring_task_cancel after the point of no return


Now that unshare_files happens in begin_new_exec after the point of no
return, io_uring_task_cancel can also happen later.

Effectively this means io_uring activities for a task are only canceled
when exec succeeds.

Signed-off-by: Eric W. Biederman <ebiederm@...ssion.com>
---

This is against my exec-for-v5.11 branch

 fs/exec.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index 14fae2ec1c9d..9e9368603168 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1257,6 +1257,11 @@ int begin_new_exec(struct linux_binprm * bprm)
 	if (retval)
 		goto out;
 
+	/*
+	 * Cancel any io_uring activity across execve
+	 */
+	io_uring_task_cancel();
+
 	/* Ensure the files table is not shared. */
 	retval = unshare_files();
 	if (retval)
@@ -1783,11 +1788,6 @@ static int bprm_execve(struct linux_binprm *bprm,
 	struct file *file;
 	int retval;
 
-	/*
-	 * Cancel any io_uring activity across execve
-	 */
-	io_uring_task_cancel();
-
 	retval = prepare_bprm_creds(bprm);
 	if (retval)
 		return retval;
-- 
2.20.1