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 <axboe@xxxxxxxxx>
---
fs/io_uring.c | 11 +++++++++++
1 file changed, 11 insertions(+)
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);
}
--
2.28.0
