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

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Message-ID: <4371a592-6686-c535-4daf-993dedb43cd4@gnuweeb.org>
Date:   Thu, 3 Mar 2022 06:20:09 +0700
From:   Ammar Faizi <ammarfaizi2@...weeb.org>
To:     Yazen Ghannam <yazen.ghannam@....com>
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@...weeb.org>,
        Jiri Hladky <hladky.jiri@...glemail.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH v4 2/2] x86/mce/amd: Fix memory leak when
 `threshold_create_bank()` fails

On 3/3/22 12:26 AM, Yazen Ghannam wrote:
> Hi Ammar,

Hi Yazen,

> ...
> The threshold interrupt handler uses this pointer. I think the goal here is to
> set this pointer when the list is fully formed and clear this pointer before
> making any changes to the list. Otherwise, the interrupt handler will operate
> on incomplete data if an interrupt comes in the middle of these updates.
> 
> The changes below should deal with memory leak issue while avoiding a race
> with the threshold interrupt. What do you think?

Thanks for taking a look into this. I didn't notice that before. The
changes look good to me, extra improvements:

1) _mce_threshold_remove_device() should be static as we don't use it
    in another translation unit.
2) Minor cleanup, we don't need "goto out_err", just early return
    directly.

I will fold them in...

-- 
Ammar Faizi