kdb: use memmove instead of overlapping memcpy

BugLink: https://bugs.launchpad.net/bugs/1811077

commit 2cf2f0d5 upstream.

gcc discovered that the memcpy() arguments in kdbnearsym() overlap, so
we should really use memmove(), which is defined to handle that correctly:

In function 'memcpy',
    inlined from 'kdbnearsym' at /git/arm-soc/kernel/debug/kdb/kdb_support.c:132:4:
/git/arm-soc/include/linux/string.h:353:9: error: '__builtin_memcpy' accessing 792 bytes at offsets 0 and 8 overlaps 784 bytes at offset 8 [-Werror=restrict]
  return __builtin_memcpy(p, q, size);
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

kernel/debug/kdb/kdb_support.c

@@ -129,13 +129,13 @@ int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab)
 		}
 		if (i >= ARRAY_SIZE(kdb_name_table)) {
 			debug_kfree(kdb_name_table[0]);
-			memcpy(kdb_name_table, kdb_name_table+1,
+			memmove(kdb_name_table, kdb_name_table+1,
 			       sizeof(kdb_name_table[0]) *
 			       (ARRAY_SIZE(kdb_name_table)-1));
 		} else {
 			debug_kfree(knt1);
 			knt1 = kdb_name_table[i];
-			memcpy(kdb_name_table+i, kdb_name_table+i+1,
+			memmove(kdb_name_table+i, kdb_name_table+i+1,
 			       sizeof(kdb_name_table[0]) *
 			       (ARRAY_SIZE(kdb_name_table)-i-1));
 		}