[PATCH 3.18 026/120] powerpc/kdump: Handle crashkernel memory reservation failure

Greg Kroah-Hartman
2018-10-11T15:38:38Z

From: Hari Bathini <hbathini@linux.ibm.com>

[ Upstream 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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/powerpc/kernel/machine_kexec.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c
@@ -186,7 +186,12 @@ 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)