powerpc/kdump: Handle crashkernel memory reservation failure

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>

diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
index 936c7e2..b534013 100644 (file)
--- 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)