Re: [PATCH V3 3/3] Assemble: cleanup the failure path

[Guoqing Jiang <gqjiang@xxxxxxxx>]

On 08/20/2018 10:28 AM, Guoqing Jiang wrote:
> On 08/17/2018 08:08 PM, Tkaczyk, Mariusz wrote:
> > Hi,
> > After this patch I found "double free or corruption".
> >
> > Scenario:
> >
> > mdadm -CR /dev/md/vol -l0 -e 1.2 -n2 /dev/sd[b-c] --assume-clean
> > mdadm -Ss
> > mdadm -A /dev/md127 /dev/sd[b-c] --update metadata
> >
> >
> >
> > *** Error in `mdadm': double free or corruption (!prev):
>
>
> Could you try below changes?
>
> diff --git a/Assemble.c b/Assemble.c
> index 23892a3720ac..9d0bc1000f96 100644
> --- a/Assemble.c
> +++ b/Assemble.c
> @@ -1536,6 +1536,11 @@ try_again:
>                               &most_recent, &bestcnt, &best, inargv);
>         if (devcnt < 0) {
>                 mdfd = -3;
> +               /*
> +                * devices is already freed in load_devices, so set 
> devices
> +                * to NULL to avoid double free devices.
> +                */
> +               devices = NULL;
>                 goto out;
>         }

Maybe we need to clean these resources as well in below case.

@@ -594,6 +594,9 @@ static int load_devices(struct devs *devices, char 
*devmap,
                        if (strcmp(c->update, "ppl") == 0 &&
                            ident->bitmap_fd >= 0) {
                                pr_err("PPL is not compatible with 
bitmap\n");
+                               close(mdfd);
+                               free(devices);
+                               free(devmap);
                                return -1;
                        }


Thanks,
Guoqing