From: Pavel Begunkov <asml.silence@xxxxxxxxx>
commit 9a472ef7a3690ac0b77ebfb04c88fa795de2adea upstream.
We can't just go over linked requests because it may race with linked
timeouts. Take ctx->completion_lock in that case.
Cc: stable@xxxxxxxxxxxxxxx # v5.7+
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/io_uring.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8176,7 +8176,21 @@ static bool io_timeout_remove_link(struc
static bool io_cancel_link_cb(struct io_wq_work *work, void *data)
{
- return io_match_link(container_of(work, struct io_kiocb, work), data);
+ struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+ bool ret;
+
+ if (req->flags & REQ_F_LINK_TIMEOUT) {
+ unsigned long flags;
+ struct io_ring_ctx *ctx = req->ctx;
+
+ /* protect against races with linked timeouts */
+ spin_lock_irqsave(&ctx->completion_lock, flags);
+ ret = io_match_link(req, data);
+ spin_unlock_irqrestore(&ctx->completion_lock, flags);
+ } else {
+ ret = io_match_link(req, data);
+ }
+ return ret;
}
static void io_attempt_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req)
