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authorPavel Begunkov <asml.silence@gmail.com>2020-10-13 09:43:56 +0100
committerJens Axboe <axboe@kernel.dk>2020-10-17 09:25:42 -0600
commit368c5481ae7c6a9719c40984faea35480d9f4872 (patch)
treecfc458c06932434a70277ec75cb1db4f3d0bd778
parent035fbafc7a54b8c7755b3c508b8f3ab6ff3c8d65 (diff)
downloadlinux-368c5481ae7c6a9719c40984faea35480d9f4872.tar.gz
io_uring: don't set COMP_LOCKED if won't put
__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@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--fs/io_uring.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 717dd5d38d757..f0f4b5b5c2a0d 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;