Re: [PATCH] btrfs: backref: this patch fixes a null pointer dereference bug.

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

[-- Attachment #1.1: Type: text/plain, Size: 2228 bytes --]



On 2020/8/7 上午11:34, Boleyn Su wrote:
> Thanks for the review. BTW, do I need to do anything else or just leave
> it to you?
>

If you mean adding the extra reviewed-by tags, no. It's handled by the
awesome maintainer David.

But if you mean to find more btrfs bugs, then keep going your awesome work!

Thanks,
Qu

> On Thu, Aug 6, 2020 at 4:04 PM Qu Wenruo <quwenruo.btrfs@gmx.com
> <mailto:quwenruo.btrfs@gmx.com>> wrote:
> 
> 
> 
>     On 2020/8/6 下午2:31, Boleyn Su wrote:
>     > The `if (!ret)` check will always be false and it may result in
>     ret->path
>     > being dereferenced while it is a null pointer.
>     >
>     > Fixes: a37f232b7b65 ("btrfs: backref: introduce the skeleton of
>     btrfs_backref_iter")
>     > Cc: Chris Mason <clm@fb.com <mailto:clm@fb.com>>
>     > Cc: Josef Bacik <josef@toxicpanda.com <mailto:josef@toxicpanda.com>>
>     > Cc: David Sterba <dsterba@suse.com <mailto:dsterba@suse.com>>
>     > Cc: Boleyn Su <boleyn.su@gmail.com <mailto:boleyn.su@gmail.com>>
>     > Cc: linux-btrfs@vger.kernel.org <mailto:linux-btrfs@vger.kernel.org>
>     > Signed-off-by: Boleyn Su <boleynsu@google.com
>     <mailto:boleynsu@google.com>>
> 
>     Nice catch.
> 
>     Reviewed-by: Qu Wenruo <wqu@suse.com <mailto:wqu@suse.com>>
> 
>     Thanks,
>     Qu
>     > ---
>     >  fs/btrfs/backref.c | 2 +-
>     >  1 file changed, 1 insertion(+), 1 deletion(-)
>     >
>     > diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
>     > index ea10f7bc9..ea1c28ccb 100644
>     > --- a/fs/btrfs/backref.c
>     > +++ b/fs/btrfs/backref.c
>     > @@ -2303,7 +2303,7 @@ struct btrfs_backref_iter
>     *btrfs_backref_iter_alloc(
>     >               return NULL;
>     > 
>     >       ret->path = btrfs_alloc_path();
>     > -     if (!ret) {
>     > +     if (!ret->path) {
>     >               kfree(ret);
>     >               return NULL;
>     >       }
>     >
> 
> 
> 
> -- 
> Boleyn Su (simplified Chinese: 苏蕉; traditional Chinese: 蘇蕉; Pinyin:
> Sū Jiāo; Katakana: スージャオ)
> 
> My PGP public key is available at boleyn.su/pgp <https://boleyn.su/pgp>.


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]