linux-kernel - [PATCH 4.8 52/96] s390/kexec: use node 0 when re-adding crash kernel memory

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Message-Id: <20170106214229.822796735@linuxfoundation.org>
Date:   Fri,  6 Jan 2017 22:43:40 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Heiko Carstens <heiko.carstens@...ibm.com>,
        Martin Schwidefsky <schwidefsky@...ibm.com>
Subject: [PATCH 4.8 52/96] s390/kexec: use node 0 when re-adding crash kernel memory

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Heiko Carstens <heiko.carstens@...ibm.com>

commit 9f88eb4df728aebcd2ddd154d99f1d75b428b897 upstream.

When re-adding crash kernel memory within setup_resources() the
function memblock_add() is used. That function will add memory by
default to node "MAX_NUMNODES" instead of node 0, like the memory
detection code does. In case of !NUMA this will trigger this warning
when the kernel generates the vmemmap:

Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead
WARNING: CPU: 0 PID: 0 at mm/memblock.c:1261 memblock_virt_alloc_internal+0x76/0x220
CPU: 0 PID: 0 Comm: swapper Not tainted 4.9.0-rc6 #16
Call Trace:
 [<0000000000d0b2e8>] memblock_virt_alloc_try_nid+0x88/0xc8
 [<000000000083c8ea>] __earlyonly_bootmem_alloc.constprop.1+0x42/0x50
 [<000000000083e7f4>] vmemmap_populate+0x1ac/0x1e0
 [<0000000000840136>] sparse_mem_map_populate+0x46/0x68
 [<0000000000d0c59c>] sparse_init+0x184/0x238
 [<0000000000cf45f6>] paging_init+0xbe/0xf8
 [<0000000000cf1d4a>] setup_arch+0xa02/0xae0
 [<0000000000ced75a>] start_kernel+0x72/0x450
 [<0000000000100020>] _stext+0x20/0x80

If NUMA is selected numa_setup_memory() will fix the node assignments
before the vmemmap will be populated; so this warning will only appear
if NUMA is not selected.

To fix this simply use memblock_add_node() and re-add crash kernel
memory explicitly to node 0.

Reported-and-tested-by: Christian Borntraeger <borntraeger@...ibm.com>
Fixes: 4e042af463f8 ("s390/kexec: fix crash on resize of reserved memory")
Signed-off-by: Heiko Carstens <heiko.carstens@...ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@...ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/s390/kernel/setup.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -445,7 +445,7 @@ static void __init setup_resources(void)
 	 * part of the System RAM resource.
 	 */
 	if (crashk_res.end) {
-		memblock_add(crashk_res.start, resource_size(&crashk_res));
+		memblock_add_node(crashk_res.start, resource_size(&crashk_res), 0);
 		memblock_reserve(crashk_res.start, resource_size(&crashk_res));
 		insert_resource(&iomem_resource, &crashk_res);
 	}