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Subject: Re: AMD boot woe due to "x86/mm: Cleanup pgprot_4k_2_large() and
 pgprot_large_2_4k()"
From:   Qian Cai <cai@lca.pw>
In-Reply-To: <20200422164703.GD26846@zn.tnic>
Date:   Wed, 22 Apr 2020 14:54:18 -0400
Cc:     Christoph Hellwig <hch@lst.de>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        x86 <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        kasan-dev <kasan-dev@googlegroups.com>
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Message-Id: <48A05550-75AD-40EA-921E-BAE43453AC47@lca.pw>
References: <20200422161757.GC26846@zn.tnic>
 <59604C7F-696A-45A3-BF4F-C8913E09DD4C@lca.pw>
 <20200422164703.GD26846@zn.tnic>
To:     Borislav Petkov <bp@alien8.de>
Sender: linux-kernel-owner@vger.kernel.org
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> On Apr 22, 2020, at 12:47 PM, Borislav Petkov <bp@alien8.de> wrote:
>=20
> On Wed, Apr 22, 2020 at 12:35:08PM -0400, Qian Cai wrote:
>> The config has a few extra memory debugging options enabled like
>> KASAN, debug_pagealloc, debug_vm etc.
>=20
> How about you specify exactly which CONFIG_ switches and cmdline =
options
> you have enabled deliberately? I can rhyme up the rest from the =
.config
> file.

The thing is pretty much the same debug kernel config has been used for
a few years, so I don=E2=80=99t deliberately enable anything today.

The best bet is probably to skim through the =E2=80=9CKernel hacking=E2=80=
=9D section of
the config and enable whatever you feel relevant if you have not enabled
already.

The cmdline is also in the .config via CONFIG_CMDLINE.

>=20
> Full dmesg would be good too, sent privately's fine too.

https://cailca.github.io/files/dmesg.txt

First, it comes with the dmesg that crashes and followed by the good =
dmesg
after reverting the commits (starting from line 644).=