linux-kernel - Re: [PATCH] x86/mce/amd: Fix kobject lifetime

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Date:   Fri, 14 Feb 2020 09:32:30 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     stable@...r.kernel.org
Cc:     X86 ML <x86@...nel.org>, Yazen Ghannam <Yazen.Ghannam@....com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86/mce/amd: Fix kobject lifetime

On Fri, Feb 14, 2020 at 09:28:01AM +0100, Borislav Petkov wrote:
> From: Thomas Gleixner <tglx@...utronix.de>
> 
> Accessing the MCA thresholding controls in sysfs concurrently with CPU
> hotplug can lead to a couple of KASAN-reported issues:
> 
>   BUG: KASAN: use-after-free in sysfs_file_ops+0x155/0x180
>   Read of size 8 at addr ffff888367578940 by task grep/4019
> 
> and
> 
>   BUG: KASAN: use-after-free in show_error_count+0x15c/0x180
>   Read of size 2 at addr ffff888368a05514 by task grep/4454
> 
> for example. Both result from the fact that the threshold block
> creation/teardown code frees the descriptor memory itself instead of
> defining proper ->release function and leaving it to the driver core to
> take care of that, after all sysfs accesses have completed.
> 
> Do that and get rid of the custom freeing code, fixing the above UAFs in
> the process.
> 
>   [ bp: write commit message. ]
> 
> Fixes: 95268664390b ("[PATCH] x86_64: mce_amd support for family 0x10 processors")
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> Signed-off-by: Borislav Petkov <bp@...e.de>
> Cc: <stable@...r.kernel.org>

Damn git-send-email: it read out Cc: stable and added it to the Cc list.
I've added

suppresscc = bodycc

to my .gitconfig.

Sorry stable guys.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette