linux-kernel - Re: [PATCH] mm: slub: add panic_on

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Message-ID: <20200504025138.GB18463@t490s>
Date:   Sun, 3 May 2020 22:51:38 -0400
From:   Rafael Aquini <aquini@...hat.com>
To:     Christopher Lameter <cl@...ux.com>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        akpm@...ux-foundation.org, iamjoonsoo.kim@....com,
        rientjes@...gle.com, penberg@...nel.org
Subject: Re: [PATCH] mm: slub: add panic_on_error to the debug facilities

On Sat, May 02, 2020 at 11:16:30PM +0000, Christopher Lameter wrote:
> On Fri, 1 May 2020, Rafael Aquini wrote:
> 
> > Sometimes it is desirable to override SLUB's debug facilities
> > default behavior upon stumbling on a cache or object error
> > and just stop the execution in order to grab a coredump, at
> > the error-spotting time, instead of trying to fix the issue
> > and report in an attempt to keep the system rolling.
> 
> The stopping of execution on an error is the default behavior. Usually
> you get some OOPS somewhere when data is corrupted and that causes a core
> dump.
> 
> SLUB can fix the issue and continue if enabled by specifying special
> options on boot. That is *not* the default.
>
It is the default behavior when slub_debug is turned on, which is what
this patch is trying to override, when needed. We've been seeing the
need for such feature as, most often than not, by letting the system
running to crash somewhere else after hitting occurrences reported by 
slub_debug ends up clobbering clues to the original issue.

-- Rafael