Re: WARNING in get_pat_info
From: David Hildenbrand
Date: Thu Oct 17 2024 - 15:27:48 EST
On 16.08.24 11:44, lee bruce wrote:
Hello, I found a bug titled "WARNING in get_pat_info" with modified
syzkaller in the lasted upstream and lasted mm branches.
Below report is from 6.10.0, which is not precisely "latest upstream",
but I assume you have similar reports on upstream?
commit 04c35ab3bdae7fefbd7c7a7355f29fa03a035221
Author: David Hildenbrand <david@xxxxxxxxxx>
Date: Wed Apr 3 23:21:30 2024 +0200
x86/mm/pat: fix VM_PAT handling in COW mappings
Was part of v6.9, but this is a different issue.
If you fix this issue, please add the following tag to the commit:
Reported-by: xingwei lee <xrivendell7@xxxxxxxxx>
Reported-by: yuxin wang <wang1315768607@xxxxxxx>
TITLE: WARNING in get_pat_info
------------[ cut here ]------------
WARNING: CPU: 2 PID: 12458 at arch/x86/mm/pat/memtype.c:1002
get_pat_info+0x4b6/0x5c0 arch/x86/mm/pat/memtype.c:1002
This is the WARN_ON_ONCE(1) in get_pat_info(). We don't find any page in
the mapping, so it vanished already.
I thought we discovered that already recently and discussed it here:
https://lore.kernel.org/all/20240712144244.3090089-1-peterx@xxxxxxxxxx/T/#u
Which was supposed to fix this problem IIRC.
That patch result in other issues, and my analysis about them is here:
https://lore.kernel.org/all/8da2b3bf-b9bf-44e3-88ff-750dc91c2388@xxxxxxxxxx/
We didn't have a report from an in-tree driver, so we decided to "not
care" about these reports:
https://lore.kernel.org/all/116ca902-103d-47cb-baf0-905983baf9bb@xxxxxxxxxx/
But I don't see Peter's patch upstream.
Peter, do you recall what the conclusion on that was?
--
Cheers,
David / dhildenb