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To:     <miklos@szeredi.hu>
CC:     <mszeredi@redhat.com>, <linux-fsdevel@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, linfeilong <linfeilong@huawei.com>,
        lihaotian <lihaotian9@huawei.com>
From:   Zhiqiang Liu <liuzhiqiang26@huawei.com>
Subject: [PATCH] fuse: check whether fuse_request_alloc returns NULL in
 fuse_simple_request
Message-ID: <ffefa3f4-4090-f7dd-97d4-27b8a8cb262f@huawei.com>
Date:   Thu, 22 Oct 2020 21:13:00 +0800
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In fuse_simple_request func, we will call fuse_request_alloc func to alloc
one request from fuse_req_cachep when args->force is true. However, the
return value of fuse_request_alloc func is not checked whether it is NULL.
If allocating request fails, access-NULL-pointer problem will occur.

Here, we check the return value of fuse_request_alloc func.

Fixes: 7213394c4e18 ("fuse: simplify request allocation")
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Signed-off-by: Haotian Li <lihaotian9@huawei.com>
---
 fs/fuse/dev.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 02b3c36b3676..f7dd33ae8e31 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -481,6 +481,8 @@ ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
 	if (args->force) {
 		atomic_inc(&fc->num_waiting);
 		req = fuse_request_alloc(GFP_KERNEL | __GFP_NOFAIL);
+		if (!req)
+			return -ENOMEM;

 		if (!args->nocreds)
 			fuse_force_creds(fc, req);
-- 
2.19.1