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

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Message-Id: <995A3749-4BC9-4217-8BAF-F10A13208F63@lca.pw>
Date:   Fri, 1 May 2020 18:00:45 -0400
From:   Qian Cai <cai@....pw>
To:     Rafael Aquini <aquini@...hat.com>
Cc:     Linux-MM <linux-mm@...ck.org>, LKML <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        David Rientjes <rientjes@...gle.com>,
        Pekka Enberg <penberg@...nel.org>, cl@...ux.com
Subject: Re: [PATCH] mm: slub: add panic_on_error to the debug facilities



> On May 1, 2020, at 5:54 PM, Rafael Aquini <aquini@...hat.com> wrote:
> 
> On Fri, May 01, 2020 at 05:29:19PM -0400, Qian Cai wrote:
>> 
>> 
>>> On May 1, 2020, at 5:15 PM, Rafael Aquini <aquini@...hat.com> 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.
>>> 
>>> This patch introduces a new debug flag SLAB_PANIC_ON_ERROR,
>>> along with its related SLUB-machinery, in order to extend
>>> current slub_debug facilites and provide the aforementioned
>>> behavior override.
>> 
>> Instead of adding those things everywhere. How about adding something like panic_on_taint? Then, you could write specific taint flags you are interested in to that file because slab_bug() will taint it TAINT_BAD_PAGE.
>> 
> It seems like a good idea which also would required "adding things"
> elsewhere, but doesn't look mutually exclusive with the approach here.

No, it is mutually exclusive because panic_on_taint would do this same thing but saner.

The thing is that this request came up over and over again where people may want to panic the kernel because of TAINT_BAD_PAGE or some other places due to tainted.