Re: [PATCH] ntfs3: use __GFP_NOWARN allocation at wnd_init()

[Konstantin Komarov <almaz.alexandrovich@paragon-software.com>]

On 10/2/22 17:39, Tetsuo Handa wrote:
> syzbot is reporting too large allocation at wnd_init() [1], for a crafted
> filesystem can become wnd->nwnd close to UINT_MAX. Add __GFP_NOWARN in
> order to avoid too large allocation warning, than exhausting memory by
> using kvcalloc().
> 
> Link: https://syzkaller.appspot.com/bug?extid=fa4648a5446460b7b963 [1]
> Reported-by: syzot <syzbot+fa4648a5446460b7b963@syzkaller.appspotmail.com>
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> ---
> Sorry, forgot to update subject line.
> 
>   fs/ntfs3/bitmap.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/ntfs3/bitmap.c b/fs/ntfs3/bitmap.c
> index 5d44ceac855b..90f3c4e84856 100644
> --- a/fs/ntfs3/bitmap.c
> +++ b/fs/ntfs3/bitmap.c
> @@ -661,7 +661,7 @@ int wnd_init(struct wnd_bitmap *wnd, struct super_block *sb, size_t nbits)
>   	if (!wnd->bits_last)
>   		wnd->bits_last = wbits;
>   
> -	wnd->free_bits = kcalloc(wnd->nwnd, sizeof(u16), GFP_NOFS);
> +	wnd->free_bits = kcalloc(wnd->nwnd, sizeof(u16), GFP_NOFS | __GFP_NOWARN);
>   	if (!wnd->free_bits)
>   		return -ENOMEM;
>   

Applied, thanks!