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Message-ID: <981d7ed4-8554-73ca-bfd1-2d89e4e91af3@redhat.com>
Date:   Sat, 7 May 2022 18:40:16 +0200
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Subject: Re: [PATCH] fbdev: efifb: Fix a use-after-free due early fb_info
 cleanup
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To:     Lucas De Marchi <lucas.demarchi@intel.com>
Cc:     linux-fbdev@vger.kernel.org,
        Andrzej Hajda <andrzej.hajda@intel.com>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org, Peter Jones <pjones@redhat.com>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Helge Deller <deller@gmx.de>
References: <20220506132225.588379-1-javierm@redhat.com>
 <20220507162053.auo2idd5twvnxatj@ldmartin-desk2>
From:   Javier Martinez Canillas <javierm@redhat.com>
In-Reply-To: <20220507162053.auo2idd5twvnxatj@ldmartin-desk2>
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Hello Lucas,

On 5/7/22 18:20, Lucas De Marchi wrote:
> On Fri, May 06, 2022 at 03:22:25PM +0200, Javier Martinez Canillas wrote:
>> Commit d258d00fb9c7 ("fbdev: efifb: Cleanup fb_info in .fb_destroy rather
>> than .remove") attempted to fix a use-after-free error due driver freeing
>> the fb_info in the .remove handler instead of doing it in .fb_destroy.
>>
>> But ironically that change introduced yet another use-after-free since the
>> fb_info was still used after the free.
>>
>> This should fix for good by freeing the fb_info at the end of the handler.
>>
>> Fixes: d258d00fb9c7 ("fbdev: efifb: Cleanup fb_info in .fb_destroy rather than .remove")
> 
> are these patches going through any CI before being applied? Maybe would
> be a good idea to cc intel-gfx mailing list on these fixes to have Intel
> CI to pick them up for some tests?
>

I Cc'ed intel-gfx for this particular patch. I should had done it for the
previous patches too, but I wasn't aware that Cc'ing that list would make
it run on your CI.

I tested locally the offending patch on an EFI platform before applying it
and I don't know why it didn't fail there. Sorry all for the inconvenience.
 
> pushed to drm-misc-fixes where the previous patch was applied.
> 

Thanks.

-- 
Best regards,

Javier Martinez Canillas
Linux Engineering
Red Hat