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From:   Song Liu <song@kernel.org>
Date:   Fri, 19 Nov 2021 21:23:28 -1000
Message-ID: <CAPhsuW7SCEXrU3AL8isD-3NwH+ChgwbUAR6y+6xDVRbZTFnEJg@mail.gmail.com>
Subject: Re: [PATCH] drivers/md: fix potential memleak
To:     =?UTF-8?B?6LW15Yab5aWO?= <bernard@vivo.com>
Cc:     linux-raid <linux-raid@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
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On Tue, Nov 16, 2021 at 9:57 PM =E8=B5=B5=E5=86=9B=E5=A5=8E <bernard@vivo.c=
om> wrote:
>
>
>
> -----=E9=82=AE=E4=BB=B6=E5=8E=9F=E4=BB=B6-----
> =E5=8F=91=E4=BB=B6=E4=BA=BA: bernard@vivo.com <bernard@vivo.com> =E4=BB=
=A3=E8=A1=A8 Song Liu
> =E5=8F=91=E9=80=81=E6=97=B6=E9=97=B4: 2021=E5=B9=B411=E6=9C=8817=E6=97=A5=
 15:06
> =E6=94=B6=E4=BB=B6=E4=BA=BA: =E8=B5=B5=E5=86=9B=E5=A5=8E <bernard@vivo.co=
m>
> =E6=8A=84=E9=80=81: linux-raid <linux-raid@vger.kernel.org>; open list <l=
inux-kernel@vger.kernel.org>
> =E4=B8=BB=E9=A2=98: Re: [PATCH] drivers/md: fix potential memleak
>
> On Sun, Nov 14, 2021 at 7:18 PM Bernard Zhao <bernard@vivo.com> wrote:
> >
> > In function get_bitmap_from_slot, when md_bitmap_create failed,
> > md_bitmap_destroy must be called to do clean up.
>
> >Could you please explain which variable(s) need clean up?
>
> Hi Song:
> The follow is the function md_bitmap_create`s annotation :
> /*
>  * initialize the bitmap structure
>  * if this returns an error, bitmap_destroy must be called to do clean up
>  * once mddev->bitmap is set
>  */
> struct bitmap *md_bitmap_create(struct mddev *mddev, int slot)
>
> It is mentioned that bitmap_destroy needs to be called to do clean up.
> Other functions which called md_bitmap_create in the same file also calle=
d md_bitmap_create to clean up(in the error branch), but this one didn`t.
> I am not sure if there is some gap?

I don't think we need to call md_bitmap_destroy in some of these cases.
Please read the code carefully can decide where these are needed based
on the logic of the code.

Thanks,
Song