| Message ID | 4de3685e185832a92a572df2be2c735d2e21a83d.1684506056.git.asml.silence@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [1/1] io_uring: annotate offset timeout races | expand |
On Fri, 19 May 2023 15:21:16 +0100, Pavel Begunkov wrote: > 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(). > > Applied, thanks! [1/1] io_uring: annotate offset timeout races commit: 5498bf28d8f2bd63a46ad40f4427518615fb793f Best regards,
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.
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> --- io_uring/timeout.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)