Re: [PATCH] ovl: fix memory leak in ovl_parse_param

From: Amir Goldstein <amir73il@gmail.com>
To: Edward Adam Davis <eadavis@qq.com>
Cc: syzbot+26eedf3631650972f17c@syzkaller.appspotmail.com,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-unionfs@vger.kernel.org, miklos@szeredi.hu,
	syzkaller-bugs@googlegroups.com
Subject: Re: [PATCH] ovl: fix memory leak in ovl_parse_param
Date: Sun, 12 Nov 2023 16:36:13 +0200	[thread overview]
Message-ID: <CAOQ4uxgVPMHJifBZdrFwn+HoUTrj2Ma9ixrwurvU+=MUYB1_Tg@mail.gmail.com> (raw)
In-Reply-To: <tencent_3FF186FD92C8C658498FEEEE6EDACC8BA706@qq.com>

On Sun, Nov 12, 2023 at 12:35 PM Edward Adam Davis <eadavis@qq.com> wrote:
>
> After failing to parse parameters in ovl_parse_param_lowerdir(), it is
> necessary to update ctx->nr with the correct nr before using
> ovl_reset_lowerdirs() to release l->name.
>
> Reported-and-tested-by: syzbot+26eedf3631650972f17c@syzkaller.appspotmail.com
> Signed-off-by: Edward Adam Davis <eadavis@qq.com>
> ---
>  fs/overlayfs/params.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c
> index ddab9ea267d1..1f73f0173015 100644
> --- a/fs/overlayfs/params.c
> +++ b/fs/overlayfs/params.c
> @@ -530,6 +530,7 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc)
>         return 0;
>
>  out_put:
> +       ctx->nr = nr;
>         ovl_reset_lowerdirs(ctx);
>
>  out_err:
> --
> 2.25.1
>

Thanks for the patch!

I prefer to fix it by eliminating the local vars instead of
syncing with them:

I've kept your commit message and tagged you as Co-authored-by:
https://github.com/amir73il/linux/commit/97d58994e880ccb19e1b9b935928538903fca41c

Thanks,
Amir.