linux-kernel - Re: [PATCH] mm: mmap: Merge vma after call

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <8c56c567495149fdba97c7931ac4492d@huawei.com>
Date:   Tue, 14 Jul 2020 03:55:56 +0000
From:   linmiaohe <linmiaohe@...wei.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
CC:     "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mm: mmap: Merge vma after call_mmap() if possible

Andrew Morton <akpm@...ux-foundation.org> wrote:
> On Tue, 14 Jul 2020 11:07:44 +0800 linmiaohe <linmiaohe@...wei.com> wrote:
>
>> The vm_flags may be changed after call_mmap() because drivers may set 
>> some flags for their own purpose. As a result, we failed to merge the 
>> adjacent vma due to the different vm_flags as userspace can't pass in the same one.
>> Try to merge vma after call_mmap() to fix this issue.
>
>Which drivers do this?

I searched the code and I see many drivers change the vm_flags, such as aio_ring_mmap set
VM_DONTEXPAND and amdgpu_mmap , binder_mmap also change the vm_flags , and so on...

Thanks.