[Ocfs2-tools-devel] [PATCH V1] mount.ocfs2: Fix double free problems when remounting a device

[Joseph Qi]

On 18/2/11 20:39, Shichangkuo wrote:
> From 60985d3705d401427c5db4116716fc5bc5223662 Mon Sep 17 00:00:00 2001
> From: shichangkuo <shi.changkuo at h3c.com>
> Date: Wed, 7 Feb 2018 17:25:08 +0800
> Subject: [PATCH] mount.ocfs2: Fix double free problems when remounting a
>  device
> 
The above should be eliminated in your patch body.

> When remounting a device, the issue happens:
> ~# mount -o remount,rw /vms/share
> *** Error in `/sbin/mount.ocfs2': double free or corruption (!prev): 0x0000000000b305a0
> *** Aborted
> 
> When updating the mtab, we should free the old mnt_opts, and duplicate
> a new one from instead->mnt_opts.
> 
> Signed-off-by: shichangkuo <shi.changkuo at h3c.com>
> ---
>  mount.ocfs2/fstab.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/mount.ocfs2/fstab.c b/mount.ocfs2/fstab.c
> index d3fc617..59cd369 100644
> --- a/mount.ocfs2/fstab.c
> +++ b/mount.ocfs2/fstab.c
> @@ -612,7 +612,8 @@ update_mtab (const char *dir, struct my_mntent *instead) {
>                         }
>                 } else {
>                         /* A remount */
> -                       mc->m.mnt_opts = instead->mnt_opts;
> +                       my_free(mc->m.mnt_opts);
Why we have to free here?

Thanks,
Joseph

> +                       mc->m.mnt_opts = xstrdup(instead->mnt_opts);
>                 }
>         } else if (instead) {
>                 /* not found, add a new entry */
> --
> 1.7.9.5