Re: [PATCH 1/1] ext4: fix crash on BUG_ON in ext4_alloc_group_tables

[Baokun Li]

On 2024/9/27 0:29, Eric Sandeen wrote:
> On 9/26/24 11:04 AM, Eric Sandeen wrote:
>
>   
> > Can you explain what the 2 cases under
> >
> > /* Avoid allocating large 'groups' array if not needed */
> >
> > are doing? I *think* the first 'if' is trying not to over-allocate for the last
> > batch of block groups that get added during a resize. What is the "else if" case
> > doing?
> (or maybe I had that backwards)
>
> Incidentally, the offending commit that this fixes (665d3e0af4d35ac) got turned
> into CVE-2023-52622, so it's quite likely that distros have backported the broken
> commit as part of the CVE game.
The commit to fix CVE-2023-52622 is commit 5d1935ac02ca5a
("ext4: avoid online resizing failures due to oversized flex bg").
This commit does not address the off by one issue above.
> So the followup fix looks a bit urgent to me.
>
> -Eric
Okay, I'll send out the fix patch today.

Regards,
Baokun
.