From: Jackie Liu liuyun01@kylinos.cn
mainline inclusion from mainline-5.4-rc1 commit 5f5ad9ced33621d353be6429c3900f8a526fcae8 category: feature bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=27 CVE: NA ---------------------------
There is a potential dangling pointer problem. we never clean shadow_req, if there are multiple link lists in this series of sqes, then the shadow_req will not reallocate, and continue to use the last one. but in the previous, his memory has been released, thus forming a dangling pointer. let's clean up him and make sure that every new link list can reapply for a new shadow_req.
Fixes: 4fe2c963154c ("io_uring: add support for link with drain") Signed-off-by: Jackie Liu liuyun01@kylinos.cn Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Zhihao Cheng chengzhihao1@huawei.com Signed-off-by: yangerkun yangerkun@huawei.com Reviewed-by: zhangyi (F) yi.zhang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- fs/io_uring.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c index 41022fd5dce7..55db30a9ebed 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2356,6 +2356,7 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, struct sqe_submit *sqes, io_queue_link_head(ctx, link, &link->submit, shadow_req, true); link = NULL; + shadow_req = NULL; } prev_was_link = (sqes[i].sqe->flags & IOSQE_IO_LINK) != 0;
@@ -2542,6 +2543,7 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit, io_queue_link_head(ctx, link, &link->submit, shadow_req, force_nonblock); link = NULL; + shadow_req = NULL; } prev_was_link = (s.sqe->flags & IOSQE_IO_LINK) != 0;