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Date: Sat, 28 Sep 2024 14:46:36 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Kees Cook <kees@kernel.org>
Cc: Vegard Nossum <vegard.nossum@oracle.com>, "Eric W. Biederman"
 <ebiederm@xmission.com>, Allen Pais <apais@linux.microsoft.com>, Roman
 Kisel <romank@linux.microsoft.com>, Xiaoming Ni <nixiaoming@huawei.com>,
 Vijay Nag <nagvijay@microsoft.com>, linux-kernel@vger.kernel.org,
 linux-hardening@vger.kernel.org
Subject: Re: [PATCH] coredump: Do not lock during 'comm' reporting
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On Sat, 28 Sep 2024 14:39:45 -0700 Kees Cook <kees@kernel.org> wrote:

> On Sat, Sep 28, 2024 at 02:35:32PM -0700, Andrew Morton wrote:
> > On Sat, 28 Sep 2024 14:08:31 -0700 Kees Cook <kees@kernel.org> wrote:
> > 
> > > The 'comm' member will always be NUL terminated,
> > 
> > Why is this?  I thought this is only true if the caller holds task_lock()?
> 
> Because it's always written with strscpy_pad(). The final byte will
> always be NUL. (And this has been true for a very long time.)

So why does __get_task_comm() need to take task_lock()?