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authorPavel Begunkov <asml.silence@gmail.com>2023-05-19 17:21:16 +0300
committerJens Axboe <axboe@kernel.dk>2023-05-20 04:56:56 +0300
commit5498bf28d8f2bd63a46ad40f4427518615fb793f (patch)
tree309046326582714d3cab7d2ff7cb5f09edbf95a3
parent3af0356c162c299a8216576b644eb72715e97cb2 (diff)
downloadlinux-5498bf28d8f2bd63a46ad40f4427518615fb793f.tar.xz
io_uring: annotate offset timeout races
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: syzbot+cb265db2f3f3468ef436@syzkaller.appspotmail.com Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/4de3685e185832a92a572df2be2c735d2e21a83d.1684506056.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--io_uring/timeout.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/io_uring/timeout.c b/io_uring/timeout.c
index fc950177e2e1..350eb830b485 100644
--- a/io_uring/timeout.c
+++ b/io_uring/timeout.c
@@ -594,7 +594,7 @@ 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.