From 6200b0ae4ea28a4bfd8eb434e33e6201b7a6a282 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sun, 13 Sep 2020 14:38:30 -0600 Subject: io_uring: don't run task work on an exiting task This isn't safe, and isn't needed either. We are guaranteed that any work we queue is on a live task (and will be run), or it goes to our backup io-wq threads if the task is exiting. Signed-off-by: Jens Axboe --- fs/io_uring.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'fs') diff --git a/fs/io_uring.c b/fs/io_uring.c index 01756a131be6..a29c8913b1f0 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1753,6 +1753,9 @@ static int io_req_task_work_add(struct io_kiocb *req, struct callback_head *cb, struct io_ring_ctx *ctx = req->ctx; int ret, notify; + if (tsk->flags & PF_EXITING) + return -ESRCH; + /* * SQPOLL kernel thread doesn't need notification, just a wakeup. For * all other cases, use TWA_SIGNAL unconditionally to ensure we're @@ -2012,6 +2015,12 @@ static inline unsigned int io_put_rw_kbuf(struct io_kiocb *req) static inline bool io_run_task_work(void) { + /* + * Not safe to run on exiting task, and the task_work handling will + * not add work to such a task. + */ + if (unlikely(current->flags & PF_EXITING)) + return false; if (current->task_works) { __set_current_state(TASK_RUNNING); task_work_run(); @@ -8184,6 +8193,8 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx, /* cancel this request, or head link requests */ io_attempt_cancel(ctx, cancel_req); io_put_req(cancel_req); + /* cancellations _may_ trigger task work */ + io_run_task_work(); schedule(); finish_wait(&ctx->inflight_wait, &wait); } -- cgit v1.2.3