In rare cases a task may be exiting while io_ring_exit_work() trying to cancel/wait its requests. It's ok for __io_sq_thread_acquire_mm() because of SQPOLL check, but is not for __io_sq_thread_acquire_files(). Play safe and fail for both of them.

Cc: stable@vger.kernel.org # 5.5+ Signed-off-by: Pavel Begunkov asml.silence@gmail.com --- fs/io_uring.c | 5 +++++ 1 file changed, 5 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c index 7af74c1ec909..b0e6d8e607a3 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1106,6 +1106,9 @@ static void io_sq_thread_drop_mm_files(void)

static int __io_sq_thread_acquire_files(struct io_ring_ctx *ctx) { + if (current->flags & PF_EXITING) + return -EFAULT; + if (!current->files) { struct files_struct *files; struct nsproxy *nsproxy; @@ -1133,6 +1136,8 @@ static int __io_sq_thread_acquire_mm(struct io_ring_ctx *ctx) { struct mm_struct *mm;

+ if (current->flags & PF_EXITING) + return -EFAULT; if (current->mm) return 0;