Re: [PATCH v2 1/4] md/raid10: fix null-ptr-deref of mreplace in raid10_sync_request

[Li Nan]

在 2023/5/27 9:21, Yu Kuai 写道:
> Hi,
>
> 在 2023/05/26 15:45, linan666@xxxxxxxxxxxxxxx 写道:
> > From: Li Nan <linan122@xxxxxxxxxx>
> >
> > need_replace will be set to 1 if no-Faulty mreplace exists, and mreplace
> > will be deref later. However, the latter check of mreplace might set
> > mreplace to NULL, null-ptr-deref occurs if need_replace is 1 at this 
> > time.
> >
> > Fix it by merging two checks into one. And replace 'need_replace' with
> > 'mreplace' because their values are always the same.
> >
> > Fixes: ee37d7314a32 ("md/raid10: Fix raid10 replace hang when new 
> > added disk faulty")
> > Signed-off-by: Li Nan <linan122@xxxxxxxxxx>
>
> Other than some nits below, this patch looks good to me, feel free too
> add:
>
> Reviewed-by: Yu Kuai <yukuai3@xxxxxxxxxx>
> > ---
> >   drivers/md/raid10.c | 13 +++++--------
> >   1 file changed, 5 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> > index 4fcfcb350d2b..e21502c03b45 100644
> > --- a/drivers/md/raid10.c
> > +++ b/drivers/md/raid10.c
> > @@ -3438,7 +3438,6 @@ static sector_t raid10_sync_request(struct mddev 
> > *mddev, sector_t sector_nr,
> >               int must_sync;
> >               int any_working;
> >               int need_recover = 0;
> > -            int need_replace = 0;
> >               struct raid10_info *mirror = &conf->mirrors[i];
> >               struct md_rdev *mrdev, *mreplace;
> > @@ -3451,10 +3450,10 @@ static sector_t raid10_sync_request(struct 
> > mddev *mddev, sector_t sector_nr,
> >                   !test_bit(In_sync, &mrdev->flags))
> >                   need_recover = 1;
> >               if (mreplace != NULL &&
> > -                !test_bit(Faulty, &mreplace->flags))
> > -                need_replace = 1;
> > +                test_bit(Faulty, &mreplace->flags))
> This can be keeped in one line.

OK, I will change it.
Thanks for your review.

--
Thanks,
Nan