efi: disable mirror feature during crashkernel

If the system has no mirrored memory or uses crashkernel.high while
kernelcore=mirror is enabled on the command line then during crashkernel,
there will be limited mirrored memory and this usually leads to OOM.

To solve this problem, disable the mirror feature during crashkernel.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ma Wupeng <[email protected]>
Acked-by: Mike Rapoport (IBM) <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

mm/mm_init.c

@@ -26,6 +26,7 @@
 #include <linux/pgtable.h>
 #include <linux/swap.h>
 #include <linux/cma.h>
+#include <linux/crash_dump.h>
 #include "internal.h"
 #include "slab.h"
 #include "shuffle.h"
@@ -381,6 +382,11 @@ static void __init find_zone_movable_pfns_for_nodes(void)
 			goto out;
 		}
 
+		if (is_kdump_kernel()) {
+			pr_warn("The system is under kdump, ignore kernelcore=mirror.\n");
+			goto out;
+		}
+
 		for_each_mem_region(r) {
 			if (memblock_is_mirror(r))
 				continue;