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Subject: Re: [PATCH 06/12] append_pathname: check the value returned by
 realloc to avoid segfault
To:     =?UTF-8?B?0JHQu9Cw0LPQvtC00LDRgNC10L3QutC+INCQ0YDRgtGR0Lw=?= 
        <artem.blagodarenko@gmail.com>
CC:     <linux-ext4@vger.kernel.org>, <liuzhiqiang26@huawei.com>,
        <linfeilong@huawei.com>
References: <266bc52e-e279-ce84-0e1f-1405b9bc6174@huawei.com>
 <07fe127f-3814-7d12-dea6-b84d9ab4410e@huawei.com>
 <1979B168-38E8-4D35-B8D7-2D47D04ED344@gmail.com>
From:   Wu Guanghao <wuguanghao3@huawei.com>
Message-ID: <596fa726-b44e-05eb-02ac-7936cc3cc9fa@huawei.com>
Date:   Tue, 25 May 2021 19:26:16 +0800
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Hello Artem Blagodarenko,

Thank you for your review, it should be chdir instead of chadir,
I will modify it in the v2 version. Next time I will take care not to make similar mistakes.
Thanks a lot.

Thanks,
Best regards,
Wu Guanghao

?? 2021/5/25 17:37, ???ݧѧԧ??էѧ??֧ߧܧ? ???????ק? д??:
> Hello Wu,
> 
> Thanks for the patch.
> 
>> On 24 May 2021, at 14:23, Wu Guanghao <wuguanghao3@huawei.com> wrote:
>>
>> In append_pathname(), we need to add a new path to save the value returned by realloc,
>> otherwise the name->path may be NULL, causing segfault
>>
>> Signed-off-by: Wu Guanghao <wuguanghao3@huawei.com>
>> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
>> ---
>> contrib/fsstress.c | 10 ++++++++--
>> 1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/contrib/fsstress.c b/contrib/fsstress.c
>> index 2a983482..530bd920 100644
>> --- a/contrib/fsstress.c
>> +++ b/contrib/fsstress.c
>> @@ -599,7 +599,7 @@ void add_to_flist(int ft, int id, int parent)
>> void append_pathname(pathname_t * name, char *str)
>> {
>> 	int len;
>> -
>> +	char *path;:
>> 	len = strlen(str);
>> #ifdef DEBUG
>> 	if (len && *str == '/' && name->len == 0) {
>> @@ -609,7 +609,13 @@ void append_pathname(pathname_t * name, char *str)
>>
>> 	}
>> #endif
>> -	name->path = realloc(name->path, name->len + 1 + len);
>> +	path = realloc(name->path, name->len + 1 + len);
>> +	if (path == NULL) {
>> +		fprintf(stderr, "fsstress: append_pathname realloc failed\n");
>> +		chadir(homedir);
> 
> Did you mean chdir() here?
> 
>> +		abort();
>> +	}
>> +	name->path = path;
>> 	strcpy(&name->path[name->len], str);
>> 	name->len += len;
>> }
>> -- 
> 
> 
> Thanks,
> Best regards,
> Artem Blagodarenko.
> 
> .
>