diff --git a/[refs] b/[refs]
index bd8fd0242938..7d0b6d51d4b2 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 8578bdf835d6d6ece6718858d351456367b8a5cf
+refs/heads/master: a752d7194c4fb5a3e767c95542d04fc5decb1d52
diff --git a/trunk/arch/x86_64/kernel/ptrace.c b/trunk/arch/x86_64/kernel/ptrace.c
index d35ec1bc696a..3a52c7bcfd12 100644
--- a/trunk/arch/x86_64/kernel/ptrace.c
+++ b/trunk/arch/x86_64/kernel/ptrace.c
@@ -141,8 +141,11 @@ static int is_at_popf(struct task_struct *child, struct pt_regs *regs)
 		case 0xf0: case 0xf2: case 0xf3:
 			continue;
 
-		/* REX prefixes */
 		case 0x40 ... 0x4f:
+			if (regs->cs != __USER_CS)
+				/* 32-bit mode: register increment */
+				return 0;
+			/* 64-bit mode: REX prefix */
 			continue;
 
 			/* CHECKME: f0, f2, f3 */