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Subject: Re: [PATCH] mm: slub: add panic_on_error to the debug facilities
From:   Qian Cai <cai@lca.pw>
In-Reply-To: <20200501215441.GE27720@optiplex-lnx>
Date:   Fri, 1 May 2020 18:00:45 -0400
Cc:     Linux-MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        David Rientjes <rientjes@google.com>,
        Pekka Enberg <penberg@kernel.org>, cl@linux.com
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Message-Id: <995A3749-4BC9-4217-8BAF-F10A13208F63@lca.pw>
References: <20200501211540.71216-1-aquini@redhat.com>
 <21CF143C-B9D1-4D3F-A875-370924265593@lca.pw>
 <20200501215441.GE27720@optiplex-lnx>
To:     Rafael Aquini <aquini@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
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> On May 1, 2020, at 5:54 PM, Rafael Aquini <aquini@redhat.com> wrote:
>=20
> On Fri, May 01, 2020 at 05:29:19PM -0400, Qian Cai wrote:
>>=20
>>=20
>>> On May 1, 2020, at 5:15 PM, Rafael Aquini <aquini@redhat.com> wrote:
>>>=20
>>> 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.
>>>=20
>>> 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.
>>=20
>> 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.
>>=20
> 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.=