From 368c5481ae7c6a9719c40984faea35480d9f4872 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Tue, 13 Oct 2020 09:43:56 +0100 Subject: [PATCH] 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 Signed-off-by: Jens Axboe --- 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 717dd5d38d75..f0f4b5b5c2a0 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; -- 2.20.1