Commit f0e20b89 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe

io_uring: fix lockup with timeouts

There is a recipe to deadlock the kernel: submit a timeout sqe with a
linked_timeout (e.g.  test_single_link_timeout_ception() from liburing),
and SIGKILL the process.

Then, io_kill_timeouts() takes @ctx->completion_lock, but the timeout
isn't flagged with REQ_F_COMP_LOCKED, and will try to double grab it
during io_put_free() to cancel the linked timeout. Probably, the same
can happen with another io_kill_timeout() call site, that is
io_commit_cqring().
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent c1e2148f
...@@ -1000,6 +1000,7 @@ static void io_kill_timeout(struct io_kiocb *req) ...@@ -1000,6 +1000,7 @@ static void io_kill_timeout(struct io_kiocb *req)
if (ret != -1) { if (ret != -1) {
atomic_inc(&req->ctx->cq_timeouts); atomic_inc(&req->ctx->cq_timeouts);
list_del_init(&req->list); list_del_init(&req->list);
req->flags |= REQ_F_COMP_LOCKED;
io_cqring_fill_event(req, 0); io_cqring_fill_event(req, 0);
io_put_req(req); io_put_req(req);
} }
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment