From mboxrd@z Thu Jan  1 00:00:00 1970
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Subject: Re: Device Tree Corrupted after unflatten_device_tree()
From: Michael Ellerman <michael@ellerman.id.au>
To: Lixin Yao <Lixin.Yao@HSTX.com>
In-Reply-To: <03D77CA4AC7F4D48A6AB5DA3F1001B3FB5BB88@exchtxus2.HSTX.global.vpn>
References: <03D77CA4AC7F4D48A6AB5DA3F1001B3FB5BB88@exchtxus2.HSTX.global.vpn>
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Date: Wed, 21 Oct 2009 10:01:31 +1100
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On Tue, 2009-10-20 at 09:10 -0700, Lixin Yao wrote:
> I use a board with MPC866T and 2.6.28 Linux Kernel.  Occasionally, the
> unflattened device is corrupted after =E2=80=9Cunflatten_device_tree()=E2=
=80=9D which
> causes crash of kernel when device tree is traversed later on.
>=20
> I looked at the fixes in lib/lmb.c, arch/powerpc/mm,
> arch/powerpc/kernel etc since 2.6.28 to 2.6.32-r4 (the most recent
> version) and could not fix my problem.
>=20
> I have had a hard time trying to determine the cause.=20
>=20
> arch/powerpc/kernel/setup_32.c
>=20
> void __init setup_arch(char **cmdline_p)
>=20
> {
>=20
>         *cmdline_p =3D cmd_line;
>=20
>         /* so udelay does something sensible, assume <=3D 1000 bogomips
> */
>=20
>         loops_per_jiffy =3D 500000000 / HZ;
>=20
>         unflatten_device_tree();
>=20
>         /* UNFLATTENED DEVICE TREE IS CORRUPTED SOMETIMES HERE */

_In what way_ is it corrupted? Bad tree structure? Bogus node/property
values, names etc.

cheers

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