---

yaml
---
r: 189413
b: refs/heads/master
c: 782a0fd
h: refs/heads/master
i:
  189411: 2598436
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 367d6acceaacff1adc44f121543effb9c060e575
+refs/heads/master: 782a0fd16723bfc0e765d789e82853d5dc424e76

trunk/arch/arm/kernel/kprobes.c

@@ -393,6 +393,14 @@ void __kprobes jprobe_return(void)
 		/*
 		 * Setup an empty pt_regs. Fill SP and PC fields as
 		 * they're needed by longjmp_break_handler.
+		 *
+		 * We allocate some slack between the original SP and start of
+		 * our fabricated regs. To be precise we want to have worst case
+		 * covered which is STMFD with all 16 regs so we allocate 2 *
+		 * sizeof(struct_pt_regs)).
+		 *
+		 * This is to prevent any simulated instruction from writing
+		 * over the regs when they are accessing the stack.
 		 */
 		"sub    sp, %0, %1		\n\t"
 		"ldr    r0, ="__stringify(JPROBE_MAGIC_ADDR)"\n\t"
@@ -410,7 +418,7 @@ void __kprobes jprobe_return(void)
 		"ldmia	sp, {r0 - pc}		\n\t"
 		:
 		: "r" (kcb->jprobe_saved_regs.ARM_sp),
-		  "I" (sizeof(struct pt_regs)),
+		  "I" (sizeof(struct pt_regs) * 2),
 		  "J" (offsetof(struct pt_regs, ARM_sp)),
 		  "J" (offsetof(struct pt_regs, ARM_pc)),
 		  "J" (offsetof(struct pt_regs, ARM_cpsr))