erofs: fix kvcalloc() misuse with __GFP_NOFAIL

  As reported by syzbot [1], kvcalloc() cannot work with  __GFP_NOFAIL.
Let's use kcalloc() instead.

[1] https://lore.kernel.org/r/0000000000007796bd05f1852ec2@google.com
Reported-by: syzbot+c3729cda01706a04fb98@syzkaller.appspotmail.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
---
 fs/erofs/zdata.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
  

On 2023/1/6 11:19, Gao Xiang wrote:
> As reported by syzbot [1], kvcalloc() cannot work with  __GFP_NOFAIL.
> Let's use kcalloc() instead.
> 
> [1] https://lore.kernel.org/r/0000000000007796bd05f1852ec2@google.com
> Reported-by: syzbot+c3729cda01706a04fb98@syzkaller.appspotmail.com

Fixes: fe3e5914e6dc ("erofs: try to leave (de)compressed_pages on stack if possible")
Fixes: 4f05687fd703 ("erofs: introduce struct z_erofs_decompress_backend")

> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
> ---
>   fs/erofs/zdata.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
> index ccf7c55d477f..08e982c77985 100644
> --- a/fs/erofs/zdata.c
> +++ b/fs/erofs/zdata.c
> @@ -1032,12 +1032,12 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be,
>   
>   	if (!be->decompressed_pages)
>   		be->decompressed_pages =
> -			kvcalloc(be->nr_pages, sizeof(struct page *),
> -				 GFP_KERNEL | __GFP_NOFAIL);
> +			kcalloc(be->nr_pages, sizeof(struct page *),
> +				GFP_KERNEL | __GFP_NOFAIL);
>   	if (!be->compressed_pages)
>   		be->compressed_pages =
> -			kvcalloc(pclusterpages, sizeof(struct page *),
> -				 GFP_KERNEL | __GFP_NOFAIL);
> +			kcalloc(pclusterpages, sizeof(struct page *),
> +				GFP_KERNEL | __GFP_NOFAIL);
>   
>   	z_erofs_parse_out_bvecs(be);
>   	err2 = z_erofs_parse_in_bvecs(be, &overlapped);
  

On 2023/1/6 13:06, Gao Xiang wrote:
> 
> 
> On 2023/1/6 11:19, Gao Xiang wrote:
>> As reported by syzbot [1], kvcalloc() cannot work with  __GFP_NOFAIL.
>> Let's use kcalloc() instead.
>>
>> [1] https://lore.kernel.org/r/0000000000007796bd05f1852ec2@google.com
>> Reported-by: syzbot+c3729cda01706a04fb98@syzkaller.appspotmail.com
> 
> Fixes: fe3e5914e6dc ("erofs: try to leave (de)compressed_pages on stack if possible")
> Fixes: 4f05687fd703 ("erofs: introduce struct z_erofs_decompress_backend")
> 
>> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
>> ---
>>   fs/erofs/zdata.c | 8 ++++----
>>   1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
>> index ccf7c55d477f..08e982c77985 100644
>> --- a/fs/erofs/zdata.c
>> +++ b/fs/erofs/zdata.c
>> @@ -1032,12 +1032,12 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be,
>>       if (!be->decompressed_pages)
>>           be->decompressed_pages =
>> -            kvcalloc(be->nr_pages, sizeof(struct page *),
>> -                 GFP_KERNEL | __GFP_NOFAIL);
>> +            kcalloc(be->nr_pages, sizeof(struct page *),
>> +                GFP_KERNEL | __GFP_NOFAIL);
>>       if (!be->compressed_pages)
>>           be->compressed_pages =
>> -            kvcalloc(pclusterpages, sizeof(struct page *),
>> -                 GFP_KERNEL | __GFP_NOFAIL);
>> +            kcalloc(pclusterpages, sizeof(struct page *),
>> +                GFP_KERNEL | __GFP_NOFAIL);

How about using kfree instead of kvfree for .decompressed_pages and
.compressed_pages memory release? It's trivial though.

Anyway, feel free to add:

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,

>>       z_erofs_parse_out_bvecs(be);
>>       err2 = z_erofs_parse_in_bvecs(be, &overlapped);
  

Hi Chao,

On 2023/1/9 18:34, Chao Yu wrote:
> On 2023/1/6 13:06, Gao Xiang wrote:
>>
>>
>> On 2023/1/6 11:19, Gao Xiang wrote:
>>> As reported by syzbot [1], kvcalloc() cannot work with  __GFP_NOFAIL.
>>> Let's use kcalloc() instead.
>>>
>>> [1] https://lore.kernel.org/r/0000000000007796bd05f1852ec2@google.com
>>> Reported-by: syzbot+c3729cda01706a04fb98@syzkaller.appspotmail.com
>>
>> Fixes: fe3e5914e6dc ("erofs: try to leave (de)compressed_pages on stack if possible")
>> Fixes: 4f05687fd703 ("erofs: introduce struct z_erofs_decompress_backend")
>>
>>> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
>>> ---
>>>   fs/erofs/zdata.c | 8 ++++----
>>>   1 file changed, 4 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
>>> index ccf7c55d477f..08e982c77985 100644
>>> --- a/fs/erofs/zdata.c
>>> +++ b/fs/erofs/zdata.c
>>> @@ -1032,12 +1032,12 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be,
>>>       if (!be->decompressed_pages)
>>>           be->decompressed_pages =
>>> -            kvcalloc(be->nr_pages, sizeof(struct page *),
>>> -                 GFP_KERNEL | __GFP_NOFAIL);
>>> +            kcalloc(be->nr_pages, sizeof(struct page *),
>>> +                GFP_KERNEL | __GFP_NOFAIL);
>>>       if (!be->compressed_pages)
>>>           be->compressed_pages =
>>> -            kvcalloc(pclusterpages, sizeof(struct page *),
>>> -                 GFP_KERNEL | __GFP_NOFAIL);
>>> +            kcalloc(pclusterpages, sizeof(struct page *),
>>> +                GFP_KERNEL | __GFP_NOFAIL);
> 
> How about using kfree instead of kvfree for .decompressed_pages and
> .compressed_pages memory release? It's trivial though.

Yeah, thanks for catching! I will send v2 to fix these.

Thanks,
Gao Xiang

> 
> Anyway, feel free to add:
> 
> Reviewed-by: Chao Yu <chao@kernel.org>
> 
> Thanks,
> 
>>>       z_erofs_parse_out_bvecs(be);
>>>       err2 = z_erofs_parse_in_bvecs(be, &overlapped);