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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>, <mszeredi@redhat.com>,
        Miklos Szeredi <miklos@szeredi.hu>
CC:     <linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        linfeilong <linfeilong@huawei.com>,
        lihaotian <lihaotian9@huawei.com>
References: <ffefa3f4-4090-f7dd-97d4-27b8a8cb262f@huawei.com>
 <b99b141d-acb8-954e-c932-7d7f402db9b3@huawei.com>
Message-ID: <fe1d287f-a1d6-cb49-da5e-7568e30bf25a@huawei.com>
Date:   Thu, 5 Nov 2020 10:09:00 +0800
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Sorry for ignoring __GFP_NOFAIL flag.
Please ignore this patch.


On 2020/11/5 9:33, Zhiqiang Liu wrote:
> 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);
>>
> 
> 
> .
>