1 files changed, 9 insertions, 0 deletions

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 4a234677e213..f4fe15ddcf94 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -210,6 +210,15 @@ void __init_or_module apply_alternatives(struct alt_instr *start,
         u8 insnbuf[MAX_PATCH_LEN];
 
         DPRINTK("%s: alt table %p -> %p\n", __func__, start, end);
+        /*
+         * The scan order should be from start to end. A later scanned
+         * alternative code can overwrite a previous scanned alternative code.
+         * Some kernel functions (e.g. memcpy, memset, etc) use this order to
+         * patch code.
+         *
+         * So be careful if you want to change the scan order to any other
+         * order.
+         */
         for (a = start; a < end; a++) {
                 u8 *instr = a->instr;
                 BUG_ON(a->replacementlen > a->instrlen);