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Date:   Fri, 30 Sep 2022 12:08:42 -0700
From:   Kees Cook <keescook@chromium.org>
To:     "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc:     Ard Biesheuvel <ardb@kernel.org>, linux-kernel@vger.kernel.org,
        regressions@lists.linux.dev, linux-fsdevel@vger.kernel.org,
        kernel-dev@igalia.com, kernel@gpiccoli.net,
        Anton Vorontsov <anton@enomsg.org>,
        Colin Cross <ccross@android.com>,
        Tony Luck <tony.luck@intel.com>,
        Thorsten Leemhuis <linux@leemhuis.info>
Subject: Re: [REGRESSION][PATCH] Revert "pstore: migrate to crypto acomp
 interface"
Message-ID: <202209301207.66D6069757@keescook>
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On Fri, Sep 30, 2022 at 03:31:17PM -0300, Guilherme G. Piccoli wrote:
> On 30/09/2022 12:51, Ard Biesheuvel wrote:
> > [...]
> > 
> > Does this help?
> > 
> > diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
> > index b2fd3c20e7c2..c0b609d7d04e 100644
> > --- a/fs/pstore/platform.c
> > +++ b/fs/pstore/platform.c
> > @@ -292,7 +292,7 @@ static int pstore_compress(const void *in, void *out,
> >                 return ret;
> >         }
> > 
> > -       return outlen;
> > +       return creq->dlen;
> >  }
> > 
> >  static void allocate_buf_for_compression(void)
> > 
> 
> Thanks a lot Ard, this seems to be the fix! Tested with lz4/zstd/deflate
> in both ramoops/efi backends, and all worked fine. It makes sense,
> outlen was modified in the previous API and not in the acomp thing, so
> it was a good catch =)
> 
> 
> >> Heheh you're right! But for something like this (pstore/dmesg
> >> compression broke for the most backends), I'd be glad if we could fix it
> >> before the release.
> > 
> > Yeah better to revert - this was not a critical change anyway. But I
> > think the tweak above should fix things (it works for me here)
> 
> Agreed - in fact seems it was reverted already. More than that, I found
> yet another small issue in the acomp refactor, a memory leak - attached
> is a patch with the fix, feel free to integrate in your acomp refactor
> when re-submitting (I mean, feel free to just integrate the code, don't
> need to send it as a separate patch/fix).
> 
> I'm also working some fixes in implicit conversions in pstore that
> aren't great (unsigned -> int in many places), I'll send some stuff next
> week.

Awesome! Thank you both! I'll probably be busy for the next week with
the merge window, but after that I'll pull new stuff into -next for
pstore. I appreciate more people poking around in the code. :)

-- 
Kees Cook