linux-kernel - Re: Debug: mm: meminfo reports 222GiB of AnonPages but sum of RSS in ps is barely 400MiB

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

Message-ID: <CA+uifjNw0W=EaUHbhq_CN8uOj0H_Yfu9JKSL1=EH6dnYkN3-ng@mail.gmail.com>
Date: Wed, 17 Jan 2024 15:50:35 +0000
From: Karim Manaouil <kmanaouil.dev@...il.com>
To: David Hildenbrand <david@...hat.com>
Cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: Debug: mm: meminfo reports 222GiB of AnonPages but sum of RSS in
 ps is barely 400MiB

On Wed, Jan 17, 2024 at 2:15 PM David Hildenbrand <david@...hat.com> wrote:

> Maybe we have something call mmget(mm) but never mmput(mm)? Are you
> running any OOT drivers or "special" hw?

That's exactly the reason! I was writing some code to count the number
of empty page tables in the system
at any given point in time. I called get_task_mm(), but I forgot to
call mmput() after that, and thus
the memory was never released.

I should have double checked, but thanks to your remark I immediately
recognised the issue and fixed it
(maybe I should have posted the code as well and mentioned that in my
original email).

--
Cheer
Karim