From: Pavel Begunkov <asml.silence@xxxxxxxxx>
__io_kill_linked_timeout() sets REQ_F_COMP_LOCKED for a linked timeout
even if it can't cancel it, e.g. it's already running. It not only races
with io_link_timeout_fn() for ->flags field, but also leaves the flag
set and so io_link_timeout_fn() may find it and decide that it holds the
lock. Hopefully, the second problem is potential.
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
fs/io_uring.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 8b780d37b686..c95e6d62b00b 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1769,6 +1769,7 @@ static bool io_link_cancel_timeout(struct io_kiocb *req)
ret = hrtimer_try_to_cancel(&io->timer);
if (ret != -1) {
+ req->flags |= REQ_F_COMP_LOCKED;
io_cqring_fill_event(req, -ECANCELED);
io_commit_cqring(ctx);
req->flags &= ~REQ_F_LINK_HEAD;
@@ -1791,7 +1792,6 @@ static bool __io_kill_linked_timeout(struct io_kiocb *req)
return false;
list_del_init(&link->link_list);
- link->flags |= REQ_F_COMP_LOCKED;
wake_ev = io_link_cancel_timeout(link);
req->flags &= ~REQ_F_LINK_TIMEOUT;
return wake_ev;
--
2.28.0
