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Date:   Thu, 31 Jan 2019 17:06:29 +1100
From:   Stephen Rothwell <sfr@canb.auug.org.au>
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     Linux Next Mailing List <linux-next@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        PowerPC <linuxppc-dev@lists.ozlabs.org>,
        Christophe Leroy <christophe.leroy@c-s.fr>
Subject: Re: linux-next: powerpc le qemu boot failure after merge of the
 akpm tree
Message-ID: <20190131170629.2cc20600@canb.auug.org.au>
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Hi all,

On Thu, 31 Jan 2019 16:38:54 +1100 Stephen Rothwell <sfr@canb.auug.org.au> =
wrote:
>
> [I am guessing that is is something in Andrew's tree that has caused
> this.]
>=20
> My qemu boot of the powerpc pseries_le_defconfig config failed like this:
>=20
> htab_hash_mask    =3D 0x1ffff
> -----------------------------------------------------
> numa:   NODE_DATA [mem 0x7ffe7000-0x7ffebfff]
> Kernel panic - not syncing: sparse_buffer_init: Failed to allocate 214748=
3648 bytes align=3D0x10000 nid=3D0 from=3Dfffffffffffffff
> CPU: 0 PID: 0 Comm: swapper Not tainted 5.0.0-rc4 #2
> Call Trace:
> [c00000000105bbd0] [c000000000b1345c] dump_stack+0xb0/0xf4 (unreliable)
> [c00000000105bc10] [c000000000111120] panic+0x168/0x3b8
> [c00000000105bcb0] [c000000000e701c8] sparse_init_nid+0x178/0x550
> [c00000000105bd70] [c000000000e709b4] sparse_init+0x210/0x238
> [c00000000105bdb0] [c000000000e468f4] initmem_init+0x1e0/0x260
> [c00000000105be80] [c000000000e3b9b0] setup_arch+0x354/0x3d4
> [c00000000105bef0] [c000000000e33afc] start_kernel+0x98/0x648
> [c00000000105bf90] [c00000000000b270] start_here_common+0x1c/0x52c

A quick bisect leads to this:

1c3c9328cde027eb875ba4692f0a5d66b0afe862 is the first bad commit
commit 1c3c9328cde027eb875ba4692f0a5d66b0afe862
Author: Mike Rapoport <rppt@linux.ibm.com>
Date:   Thu Jan 31 10:51:32 2019 +1100

    treewide: add checks for the return value of memblock_alloc*()
   =20
    Add check for the return value of memblock_alloc*() functions and call
    panic() in case of error.  The panic message repeats the one used by
    panicing memblock allocators with adjustment of parameters to include o=
nly
    relevant ones.
   =20
    The replacement was mostly automated with semantic patches like the one
    below with manual massaging of format strings.
   =20
    @@
    expression ptr, size, align;
    @@
    ptr =3D memblock_alloc(size, align);
    + if (!ptr)
    +       panic("%s: Failed to allocate %lu bytes align=3D0x%lx\n", __fun=
c__,
    size, align);
   =20
    Link: http://lkml.kernel.org/r/1548057848-15136-20-git-send-email-rppt@=
linux.ibm.com
    Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
    Reviewed-by: Guo Ren <ren_guo@c-sky.com>                [c-sky]
    Acked-by: Paul Burton <paul.burton@mips.com>            [MIPS]
    Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>    [s390]
    Reviewed-by: Juergen Gross <jgross@suse.com>            [Xen]
    Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>  [m68k]
    Cc: Catalin Marinas <catalin.marinas@arm.com>
    Cc: Christophe Leroy <christophe.leroy@c-s.fr>
    Cc: Christoph Hellwig <hch@lst.de>
    Cc: "David S. Miller" <davem@davemloft.net>
    Cc: Dennis Zhou <dennis@kernel.org>
    Cc: Greentime Hu <green.hu@gmail.com>
    Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Cc: Guan Xuetao <gxt@pku.edu.cn>
    Cc: Guo Ren <guoren@kernel.org>
    Cc: Mark Salter <msalter@redhat.com>
    Cc: Matt Turner <mattst88@gmail.com>
    Cc: Max Filippov <jcmvbkbc@gmail.com>
    Cc: Michael Ellerman <mpe@ellerman.id.au>
    Cc: Michal Simek <monstr@monstr.eu>
    Cc: Petr Mladek <pmladek@suse.com>
    Cc: Richard Weinberger <richard@nod.at>
    Cc: Rich Felker <dalias@libc.org>
    Cc: Rob Herring <robh+dt@kernel.org>
    Cc: Rob Herring <robh@kernel.org>
    Cc: Russell King <linux@armlinux.org.uk>
    Cc: Stafford Horne <shorne@gmail.com>
    Cc: Tony Luck <tony.luck@intel.com>
    Cc: Vineet Gupta <vgupta@synopsys.com>
    Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Which is just adding the panic we hit.  So, presumably, the bug is in a
preceding patch :-(

I have left the kernel not booting for today.
--=20
Cheers,
Stephen Rothwell

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