From: Pavel Begunkov <asml.silence@gmail.com>
Date: Fri, 25 Oct 2019 09:31:29 +0000 (+0300)
Subject: io_uring: Fix corrupted user_data
X-Git-Tag: v5.4-rc5~14^2~8
X-Git-Url: http://git-history.diyao.me/?a=commitdiff_plain;h=84d55dc5b9e57b513a702fbc358e1b5489651590;p=linux%2F.git

io_uring: Fix corrupted user_data

There is a bug, where failed linked requests are returned not with
specified @user_data, but with garbage from a kernel stack.

The reason is that io_fail_links() uses req->user_data, which is
uninitialised when called from io_queue_sqe() on fail path.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 1b46c72f8975..0e141d905a5b 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2448,6 +2448,8 @@ static void io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s,
 		return;
 	}
 
+	req->user_data = s->sqe->user_data;
+
 	/*
 	 * If we already have a head request, queue this one for async
 	 * submittal once the head completes. If we don't have a head but