linux-kernel - Re: [regression] oops on heavy compilations ("kernel BUG at mm/zswap.c:1005!" and "Oops: invalid opcode: 0000")

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: <EF0ABD3E-A239-4111-A8AB-5C442E759CF3@gmail.com>
Date: Mon, 2 Sep 2024 10:57:50 +0200
From: Piotr Oniszczuk <piotr.oniszczuk@...il.com>
To: Yosry Ahmed <yosryahmed@...gle.com>
Cc: Pedro Falcato <pedro.falcato@...il.com>,
 Nhat Pham <nphamcs@...il.com>,
 Matthew Wilcox <willy@...radead.org>,
 Linux regressions mailing list <regressions@...ts.linux.dev>,
 LKML <linux-kernel@...r.kernel.org>,
 Johannes Weiner <hannes@...xchg.org>,
 Linux-MM <linux-mm@...ck.org>
Subject: Re: [regression] oops on heavy compilations ("kernel BUG at
 mm/zswap.c:1005!" and "Oops: invalid opcode: 0000")



> Wiadomość napisana przez Yosry Ahmed <yosryahmed@...gle.com> w dniu 31.08.2024, o godz. 19:23:
> 
> On Sat, Aug 31, 2024 at 2:41 AM Piotr Oniszczuk
> <piotr.oniszczuk@...il.com> wrote:
>> 
>> 
>> 
>>> Wiadomość napisana przez Yosry Ahmed <yosryahmed@...gle.com> w dniu 29.08.2024, o godz. 23:54:
>>> 
>>> I also noticed that you are using z3fold as the zpool. Is the problem
>>> reproducible with zsmalloc? I wouldn't be surprised if there's a
>>> z3fold bug somewhere.
>>> 
>> 
>> Hmm - yesterday i recompiled 6.9.12 with zsmalloc and …. after 16h of continuous tests I can’t reproduce issue.
>> With zsmalloc 6.9.12 looks to me like stable.
> 
> Interesting, and a little bit what I hoped for tbh.

:-)

I tested mainline 6.10.7 with 26h test and also it is stable with zsmalloc 

> 
>> 
>> With this - what will be your advice to move forward?
> 
> Well, it's possible that some zswap change was not fully compatible
> with z3fold, or surfaced a dormant bug in z3fold. Either way, my
> recommendation is to use zsmalloc.
> I have been trying to deprecate

IMHO - isn’t bug in this report + difficulties to reproduce->fix enough to depreciate z3fold?  

> z3fold, and honestly you are the only person I have seen use z3fold in
> a while -- which is probably why no one else reported such a problem.

Well - in fact this is ArchLinux - not me.
I’m using Arch and kernel in builder machine with ArchLinux config + packaging

> 
>> Is there any possibility/way to avoid bisecting? (due limited time from my side)
> 
> So unless you have a reason to specifically use z3fold or avoid
> zsmalloc, please use zsmalloc. It should be better for you anyway. I

I see benefits already: on very memory demanding qtwebkit compile:
z3fold: swap frequently gets 6..8G from 16G available
zsmalloc: can’t see more than 1..2G
  
> doubt that you (or anyone) wants to spend time debugging a z3fold
> problem :)

lets depreciate it!