linux-kernel - Re: [PATCH -v3 1/3] resource: Fix region_intersects() vs add_memory_driver

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: <20240907202458.dfe90bfee071021706af91eb@linux-foundation.org>
Date: Sat, 7 Sep 2024 20:24:58 -0700
From: Andrew Morton <akpm@...ux-foundation.org>
To: Huang Ying <ying.huang@...el.com>
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
 linux-cxl@...r.kernel.org, Dan Williams <dan.j.williams@...el.com>, David
 Hildenbrand <david@...hat.com>, Davidlohr Bueso <dave@...olabs.net>,
 Jonathan Cameron <jonathan.cameron@...wei.com>, Dave Jiang
 <dave.jiang@...el.com>, Alison Schofield <alison.schofield@...el.com>,
 Vishal Verma <vishal.l.verma@...el.com>, Ira Weiny <ira.weiny@...el.com>,
 Alistair Popple <apopple@...dia.com>, Andy Shevchenko
 <andriy.shevchenko@...ux.intel.com>, Bjorn Helgaas <bhelgaas@...gle.com>,
 Baoquan He <bhe@...hat.com>
Subject: Re: [PATCH -v3 1/3] resource: Fix region_intersects() vs
 add_memory_driver_managed()

On Fri,  6 Sep 2024 11:07:11 +0800 Huang Ying <ying.huang@...el.com> wrote:

> On a system with CXL memory, the resource tree (/proc/iomem) related
> to CXL memory may look like something as follows.
> 
> 490000000-50fffffff : CXL Window 0
>   490000000-50fffffff : region0
>     490000000-50fffffff : dax0.0
>       490000000-50fffffff : System RAM (kmem)
> 
> Because drivers/dax/kmem.c calls add_memory_driver_managed() during
> onlining CXL memory, which makes "System RAM (kmem)" a descendant of
> "CXL Window X".  This confuses region_intersects(), which expects all
> "System RAM" resources to be at the top level of iomem_resource.  This
> can lead to bugs.
> 
> ...
> 
> Fixes: c221c0b0308f ("device-dax: "Hotplug" persistent memory for use like normal RAM")

Do you believe this should be fixed in earlier (-stable) kernels?