linux-kernel - Re: [PATCH v4 2/2] x86/mce/amd: Fix memory leak when `threshold_create

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Date:   Wed, 9 Mar 2022 20:55:55 +0000
From:   Yazen Ghannam <yazen.ghannam@....com>
To:     Ammar Faizi <ammarfaizi2@...weeb.org>
Cc:     Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Tony Luck <tony.luck@...el.com>, linux-edac@...r.kernel.org,
        linux-kernel@...r.kernel.org, gwml@...r.gnuweeb.org,
        x86@...nel.org, stable@...r.kernel.org,
        Alviro Iskandar Setiawan <alviro.iskandar@...il.com>,
        Jiri Hladky <hladky.jiri@...glemail.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Alviro Iskandar Setiawan <alviro.iskandar@...weeb.org>
Subject: Re: [PATCH v4 2/2] x86/mce/amd: Fix memory leak when
 `threshold_create_bank()` fails

On Mon, Mar 07, 2022 at 07:27:44AM +0700, Ammar Faizi wrote:
> On 3/3/22 9:32 AM, Ammar Faizi wrote:
> > It looks like this now. Yazen, Alviro, please review the
> > following patch. If you think it looks good, I will submit
> > it for the v5.
> > 
> >  From 91a447f837d502b7a040cd68f333fb98f4b941d9 Mon Sep 17 00:00:00 2001
> > From: Ammar Faizi <ammarfaizi2@...weeb.org>
> > Date: Thu, 3 Mar 2022 09:22:17 +0700
> > Subject: [PATCH v5 2/2] x86/MCE/AMD: Fix memory leak when `threshold_create_bank()` fails
> > 
> > In mce_threshold_create_device(), if threshold_create_bank() fails, the
> > @bp will be leaked, because mce_threshold_remove_device() will not free
> > the @bp. It only frees the @bp when we've already written the @bp to
> > the @threshold_banks per-CPU variable, but at the point, we haven't.
> > 
> > Fix this by extracting the cleanup part into a new static function
> > _mce_threshold_remove_device(), then use it from create/remove device
> > function. Also, eliminate the "goto out_err". Just early return inside
> > the loop if we fail.
> >

The commit message should use passive voice: no "I" or "we".

Otherwise, I think the patch looks good.

Thanks,
Yazen