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Subject: Re: [PATCH] fuse: check whether fuse_request_alloc returns NULL in
 fuse_simple_request
From:   Zhiqiang Liu <liuzhiqiang26@huawei.com>
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>,
        <fuse-devel@lists.sourceforge.net>, <Nikolaus@rath.org>,
        <kschalk@nvidia.com>, <dhowells@redhat.com>
References: <ffefa3f4-4090-f7dd-97d4-27b8a8cb262f@huawei.com>
Message-ID: <5dff2fb8-80aa-11dc-a1d5-3fc64c27ca3d@huawei.com>
Date:   Tue, 27 Oct 2020 17:24:41 +0800
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friendly ping...

On 2020/10/22 21:13, Zhiqiang Liu wrote:
> 
> 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);
>