Messages in this thread Patch in this message | | | From | Masami Hiramatsu <> | Subject | [PATCH -tip v10 11/16] arm: kprobes: Make space for instruction pointer on stack | Date | Thu, 29 Jul 2021 23:07:39 +0900 |
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Since arm's __kretprobe_trampoline() saves partial 'pt_regs' on the stack, 'regs->ARM_pc' (instruction pointer) is not accessible from the kretprobe handler. This means if instruction_pointer_set() is used from kretprobe handler, it will break the data on the stack.
Make space for instruction pointer (ARM_pc) on the stack in the __kretprobe_trampoline() for fixing this problem.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> --- Changes in v9: - Update changelog. --- arch/arm/probes/kprobes/core.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c index 67ce7eb8f285..95f23b47ba27 100644 --- a/arch/arm/probes/kprobes/core.c +++ b/arch/arm/probes/kprobes/core.c @@ -376,11 +376,13 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self, void __naked __kprobes __kretprobe_trampoline(void) { __asm__ __volatile__ ( + "sub sp, sp, #16 \n\t" "stmdb sp!, {r0 - r11} \n\t" "mov r0, sp \n\t" "bl trampoline_handler \n\t" "mov lr, r0 \n\t" "ldmia sp!, {r0 - r11} \n\t" + "add sp, sp, #16 \n\t" #ifdef CONFIG_THUMB2_KERNEL "bx lr \n\t" #else
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