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Diffstat (limited to 'arch/arm/kernel/kprobes.c')
-rw-r--r--arch/arm/kernel/kprobes.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c
index 60c62c377fa..2ba7deb3072 100644
--- a/arch/arm/kernel/kprobes.c
+++ b/arch/arm/kernel/kprobes.c
@@ -22,6 +22,7 @@
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/module.h>
+#include <linux/slab.h>
#include <linux/stop_machine.h>
#include <linux/stringify.h>
#include <asm/traps.h>
@@ -393,6 +394,14 @@ 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 +419,7 @@ 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))