* [PATCH AUTOSEL 5.9 029/147] io_uring: don't set COMP_LOCKED if won't put
[not found] <[email protected]>
@ 2020-10-26 23:47 ` Sasha Levin
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From: Sasha Levin @ 2020-10-26 23:47 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Pavel Begunkov, Jens Axboe, Sasha Levin, io-uring, linux-fsdevel
From: Pavel Begunkov <[email protected]>
[ Upstream commit 368c5481ae7c6a9719c40984faea35480d9f4872 ]
__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 <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
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 aae0ef2ec34d2..2145cf76a0d6a 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1614,6 +1614,7 @@ static bool io_link_cancel_timeout(struct io_kiocb *req)
ret = hrtimer_try_to_cancel(&req->io->timeout.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;
@@ -1636,7 +1637,6 @@ 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;
--
2.25.1
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