From: Pavel Begunkov Date: Mon, 11 Jan 2021 04:00:30 +0000 (+0000) Subject: io_uring: drop mm and files after task_work_run X-Git-Tag: io_uring-5.11-2021-01-16~5 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=d434ab6db524ab1efd0afad4ffa1ee65ca6ac097;p=linux-block.git io_uring: drop mm and files after task_work_run __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 --- diff --git a/fs/io_uring.c b/fs/io_uring.c index 2f305c097bd5..7af74c1ec909 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -7056,6 +7056,7 @@ static int io_sq_thread(void *data) if (sqt_spin || !time_after(jiffies, timeout)) { io_run_task_work(); + io_sq_thread_drop_mm_files(); cond_resched(); if (sqt_spin) timeout = jiffies + sqd->sq_thread_idle; @@ -7093,6 +7094,7 @@ static int io_sq_thread(void *data) } io_run_task_work(); + io_sq_thread_drop_mm_files(); if (cur_css) io_sq_thread_unassociate_blkcg();