diff options
Diffstat (limited to 'arch/arm/kernel/kprobes.c')
| -rw-r--r-- | arch/arm/kernel/kprobes.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c index 60c62c377fa..610e0f561c3 100644 --- a/arch/arm/kernel/kprobes.c +++ b/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)) |