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Date: Thu, 2 Aug 2018 14:02:22 -0700
From: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] mm:bugfix check return value of ioremap_prot
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To: Yang Shi <shy828301@gmail.com>
Cc: chenjie6@huawei.com, linux-mm@kvack.org, tj@kernel.org, lizefan@huawei.com, chen jie <"chen jie@chenjie6"@huwei.com>, Alexey Dobriyan <adobriyan@gmail.com>

On Thu, 2 Aug 2018 09:47:52 -0700 Yang Shi <shy828301@gmail.com> wrote:

> On Thu, Aug 2, 2018 at 12:37 AM,  <chenjie6@huawei.com> wrote:
> > From: chen jie <chen jie@chenjie6@huwei.com>
> >
> >         ioremap_prot can return NULL which could lead to an oops
> 
> What oops? You'd better to have the oops information in your commit log.

Doesn't matter much - the code is clearly buggy.

Looking at the callers, I have suspicions about
fs/proc/base.c:environ_read().  It's assuming that access_remote_vm()
returns an errno.  But it doesn't - it returns number of bytes copied.

Alexey, could you please take a look?  While in there, I'd suggest
adding some return value documentation to __access_remote_vm() and
access_remote_vm().  Thanks.