From 8950329c4a64c6d3ca0bc34711a1afbd9ce05657 Mon Sep 17 00:00:00 2001
From: Hari Bathini <hbathini@linux.ibm.com>
Date: Thu, 28 Jun 2018 10:49:56 +0530
Subject: [PATCH] powerpc/kdump: Handle crashkernel memory reservation failure

References: bsc#1143466 LTC#179600
Patch-mainline: v4.19-rc1
Git-commit: 8950329c4a64c6d3ca0bc34711a1afbd9ce05657

Memory reservation for crashkernel could fail if there are holes around
kdump kernel offset (128M). Fail gracefully in such cases and print an
error message.

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Tested-by: David Gibson <dgibson@redhat.com>
Reviewed-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/kernel/machine_kexec.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
index 936c7e2d421e..b53401334e81 100644
--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c
@@ -188,7 +188,12 @@ void __init reserve_crashkernel(void)
 			(unsigned long)(crashk_res.start >> 20),
 			(unsigned long)(memblock_phys_mem_size() >> 20));
 
-	memblock_reserve(crashk_res.start, crash_size);
+	if (!memblock_is_region_memory(crashk_res.start, crash_size) ||
+	    memblock_reserve(crashk_res.start, crash_size)) {
+		pr_err("Failed to reserve memory for crashkernel!\n");
+		crashk_res.start = crashk_res.end = 0;
+		return;
+	}
 }
 
 int overlaps_crashkernel(unsigned long start, unsigned long size)
-- 
2.22.0