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Date:   Tue, 16 Oct 2018 13:19:27 +1100
From:   Stephen Rothwell <sfr@canb.auug.org.au>
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     Linux-Next Mailing List <linux-next@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Mike Rapoport <rppt@linux.vnet.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        PowerPC <linuxppc-dev@lists.ozlabs.org>
Subject: Re: linux-next: Tree for Oct 15
Message-ID: <20181016131927.6ceba6ab@canb.auug.org.au>
In-Reply-To: <20181016130216.3a417381@canb.auug.org.au>
References: <20181015192546.15faf3a1@canb.auug.org.au>
        <20181015193914.GA9881@roeck-us.net>
        <20181016073359.3fa7bb32@canb.auug.org.au>
        <20181015222213.GA31415@roeck-us.net>
        <20181016130216.3a417381@canb.auug.org.au>
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Hi all,

On Tue, 16 Oct 2018 13:02:16 +1100 Stephen Rothwell <sfr@canb.auug.org.au> =
wrote:
>
> Reverting fe3d2a45e8079fdd7d4da1ff07f4b40bc3cb499f (and the following 2
> commits) produces a kernel that boots.

Instead of that, I applied this patch on top of linux-next and it boots
and produces a stack trace ...

From: Stephen Rothwell <sfr@canb.auug.org.au>
Date: Tue, 16 Oct 2018 13:07:01 +1100
Subject: [PATCH] mm/memblock.c: use dump_stack() instead of WARN_ON_ONCE for
 the alignment checks

Using WARN_ON_ONCE too early causes the PowerPC kernel to fail.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
---
 mm/memblock.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/mm/memblock.c b/mm/memblock.c
index 5fefc70253ee..f2ef3915a356 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1298,8 +1298,10 @@ static phys_addr_t __init memblock_alloc_range_nid(p=
hys_addr_t size,
 {
 	phys_addr_t found;
=20
-	if (WARN_ON_ONCE(!align))
+	if (!align) {
+		dump_stack();
 		align =3D SMP_CACHE_BYTES;
+	}
=20
 	found =3D memblock_find_in_range_node(size, align, start, end, nid,
 					    flags);
@@ -1423,8 +1425,10 @@ static void * __init memblock_alloc_internal(
 	if (WARN_ON_ONCE(slab_is_available()))
 		return kzalloc_node(size, GFP_NOWAIT, nid);
=20
-	if (WARN_ON_ONCE(!align))
+	if (!align) {
+		dump_stack();
 		align =3D SMP_CACHE_BYTES;
+	}
=20
 	if (max_addr > memblock.current_limit)
 		max_addr =3D memblock.current_limit;
--=20
2.18.0

So, patch "memblock: stop using implicit alignment to SMP_CACHE_BYTES"
should *not* remove the 0 -> SMP_CACHE_BYTES update from mm/memblock.c
and just add the dump_stack().
--=20
Cheers,
Stephen Rothwell

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