From 7f7b2926d92bde69f8ea3272c47d19703227b0a2 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Mon, 25 Jan 2021 07:15:07 +0000 Subject: [PATCH] io_uring: drop mm and files after task_work_run stable inclusion from stable-5.10.9 commit f7f32822a44af3b09a1641d26803a8fea714ff88 bugzilla: 47457 -------------------------------- [ Upstream commit d434ab6db524ab1efd0afad4ffa1ee65ca6ac097 ] __io_req_task_submit() run by task_work can set mm and files, but io_sq_thread() in some cases, and because __io_sq_thread_acquire_mm() and __io_sq_thread_acquire_files() do a simple current->mm/files check it may end up submitting IO with mm/files of another task. We also need to drop it after in the end to drop potentially grabbed references to them. Cc: stable@vger.kernel.org # 5.9+ Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Chen Jun Acked-by: Xie XiuQi --- fs/io_uring.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 6c356b9e87b3..cab640c10bc0 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -6841,6 +6841,7 @@ static int io_sq_thread(void *data) if (ret & SQT_SPIN) { io_run_task_work(); + io_sq_thread_drop_mm(); cond_resched(); } else if (ret == SQT_IDLE) { if (kthread_should_park()) @@ -6855,6 +6856,7 @@ static int io_sq_thread(void *data) } io_run_task_work(); + io_sq_thread_drop_mm(); if (cur_css) io_sq_thread_unassociate_blkcg(); -- GitLab