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Subject: Re: CONFIG_DEBUG_VIRTUAL breaks boot on x86-32
From:   William Kucharski <william.kucharski@oracle.com>
In-Reply-To: <4d5ee3b0-6d47-a8df-a6b3-54b0fba66ed7@linux.ee>
Date:   Tue, 26 Mar 2019 07:52:07 -0600
Cc:     LKML <linux-kernel@vger.kernel.org>, linux-mm@kvack.org
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Message-Id: <A1B7F481-4BF6-4441-8019-AE088F8A8939@oracle.com>
References: <4d5ee3b0-6d47-a8df-a6b3-54b0fba66ed7@linux.ee>
To:     Meelis Roos <mroos@linux.ee>
Sender: linux-kernel-owner@vger.kernel.org
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Does this still happen on 5.1-rc2?

Do you have idea as to what max_low_pfn() gets set to on your system at =
boot time?

=46rom the screen shot I'm guessing it MIGHT be 0x373fe, but it's hard =
to know for sure.


> On Mar 21, 2019, at 2:22 PM, Meelis Roos <mroos@linux.ee> wrote:
>=20
> I tried to debug another problem and turned on most debug options for =
memory.
> The resulting kernel failed to boot.
>=20
> Bisecting the configurations led to CONFIG_DEBUG_VIRTUAL - if I turned =
it on
> in addition to some other debug options, the machine crashed with
>=20
> kernel BUG at arch/x86/mm/physaddr.c:79!
>=20
> Screenshot at http://kodu.ut.ee/~mroos/debug_virtual-boot-hang-1.jpg
>=20
> The machine was Athlon XP with VIA KT600 chipset and 2G RAM.
>=20
> --=20
> Meelis Roos <mroos@linux.ee>
>=20