* [PATCH AUTOSEL 6.1 02/12] io_uring: annotate offset timeout races
[not found] <[email protected]>
@ 2023-07-02 19:41 ` Sasha Levin
0 siblings, 0 replies; only message in thread
From: Sasha Levin @ 2023-07-02 19:41 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Pavel Begunkov, syzbot+cb265db2f3f3468ef436, Jens Axboe,
Sasha Levin, io-uring
From: Pavel Begunkov <[email protected]>
[ Upstream commit 5498bf28d8f2bd63a46ad40f4427518615fb793f ]
It's racy to read ->cached_cq_tail without taking proper measures
(usually grabbing ->completion_lock) as timeout requests with CQE
offsets do, however they have never had a good semantics for from
when they start counting. Annotate racy reads with data_race().
Reported-by: [email protected]
Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/4de3685e185832a92a572df2be2c735d2e21a83d.1684506056.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
io_uring/timeout.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/io_uring/timeout.c b/io_uring/timeout.c
index 4c6a5666541cf..b0cf05ebcbcc3 100644
--- a/io_uring/timeout.c
+++ b/io_uring/timeout.c
@@ -545,7 +545,7 @@ int io_timeout(struct io_kiocb *req, unsigned int issue_flags)
goto add;
}
- tail = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
+ tail = data_race(ctx->cached_cq_tail) - atomic_read(&ctx->cq_timeouts);
timeout->target_seq = tail + off;
/* Update the last seq here in case io_flush_timeouts() hasn't.
--
2.39.2
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