From: Pavel Begunkov <[email protected]> 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: [email protected] # v5.7+ Signed-off-by: Pavel Begunkov <[email protected]> Signed-off-by: Jens Axboe <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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)
