Re: [PATCH] fs: f2fs: remove WARN_ON in f2fs_is_valid_blkaddr

[Chao Yu]

On 2022/4/9 9:34, Dongliang Mu wrote:
> On Sat, Apr 9, 2022 at 8:27 AM Chao Yu <chao@xxxxxxxxxx> wrote:
> > On 2022/4/8 13:22, Dongliang Mu wrote:
> > > From: Dongliang Mu <mudongliangabcd@xxxxxxxxx>
> > >
> > > In f2fs_is_valid_blkaddr, if type is DATA_GENERIC_ENHANCE or
> > > DATA_GENERIC_ENHANCE_READ, it invokes WARN_ON(1) not matter
> > > blkaddr is in the range or not.
> >
> > If we run into the path where we invoke WARN_ON(1) in f2fs_is_valid_blkaddr(),
> > It means f2fs image may be broken, or there is a bug in f2fs.
> >
> > So, do you suffer any related issue in your environment?
>
> related issue? Can you explain a little?
>
> If you mean if this warning occurs, any other issues or crash

I mean have you seen any warning info printed in the path of
f2fs_is_valid_blkaddr() before applying this patch, and if so, w/ what
reproducer? or you just figure out this patch from perspective of code
review?

Thanks,

> behaviors are generated? I tested on the syzbot. After removing the
> WARN_ON, there is no abnormal issue or crash behaviors followed with
> the corresponding reproducer.
>
>
> > Thanks,
> >
> > > Fix this by removing WARN_ON.
> > >
> > > Note that, syzbot patch testing does not incur any further issues
> > >
> > > Reported-by: syzbot+763ae12a2ede1d99d4dc@xxxxxxxxxxxxxxxxxxxxxxxxx
> > > Signed-off-by: Dongliang Mu <mudongliangabcd@xxxxxxxxx>
> > > ---
> > >    fs/f2fs/checkpoint.c | 2 --
> > >    1 file changed, 2 deletions(-)
> > >
> > > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> > > index f5366feea82d..521498b2dd8c 100644
> > > --- a/fs/f2fs/checkpoint.c
> > > +++ b/fs/f2fs/checkpoint.c
> > > @@ -158,7 +158,6 @@ static bool __is_bitmap_valid(struct f2fs_sb_info *sbi, block_t blkaddr,
> > >                f2fs_err(sbi, "Inconsistent error blkaddr:%u, sit bitmap:%d",
> > >                         blkaddr, exist);
> > >                set_sbi_flag(sbi, SBI_NEED_FSCK);
> > > -             WARN_ON(1);
> > >        }
> > >        return exist;
> > >    }
> > > @@ -196,7 +195,6 @@ bool f2fs_is_valid_blkaddr(struct f2fs_sb_info *sbi,
> > >                        f2fs_warn(sbi, "access invalid blkaddr:%u",
> > >                                  blkaddr);
> > >                        set_sbi_flag(sbi, SBI_NEED_FSCK);
> > > -                     WARN_ON(1);
> > >                        return false;
> > >                } else {
> > >                        return __is_bitmap_valid(sbi, blkaddr, type);