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

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Message-ID: <CAJD7tkbF2Cx4uRCJAN=EKDLkVC=CApiLAsYt4ZN9YcVUJZp_5g@mail.gmail.com>
Date: Tue, 27 Aug 2024 11:48:19 -0700
From: Yosry Ahmed <yosryahmed@...gle.com>
To: Piotr Oniszczuk <piotr.oniszczuk@...il.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")

On Sun, Aug 25, 2024 at 9:24 AM Piotr Oniszczuk
<piotr.oniszczuk@...il.com> wrote:
>
>
>
> > Wiadomość napisana przez Pedro Falcato <pedro.falcato@...il.com> w dniu 25.08.2024, o godz. 17:05:
> >
> > Also, could you try a memtest86 on your machine, to shake out potential hardware problems?
>
>
> I found less time consuming way to trigger issue: 12c24t cross compile of llvm with „only 16G” of ram - as this triggers many heavy swappings (top swap usage gets 8-9G out of 16G swap part)
>
> With such setup - on 6.9.12 - i’m getting not available system (due cpu soft lockup) just in 1..3h
> (usually first or second compile iteration; i wrote simple scrip compiling in loop + counting interations)

Are we sure that the soft lockup problem is related to the originally
reported problem? It seems like in v6.10 you hit a BUG in zswap
(corruption?), and in v6.9 you hit a soft lockup with a zswap lock
showing up in the splat. Not sure how they are relevant.

Is the soft lockup reproducible in v6.10 as well?

Since you have a narrow window (6.8.2 to 6.9) and a reproducer for the
soft lockup problem, can you try bisecting?

Thanks!