From cd9bc2c9258816dc934b300705076519d7375b81 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 21 Oct 2021 09:55:09 +0900 Subject: arm64: Recover kretprobe modified return address in stacktrace Since the kretprobe replaces the function return address with the kretprobe_trampoline on the stack, stack unwinder shows it instead of the correct return address. This checks whether the next return address is the __kretprobe_trampoline(), and if so, try to find the correct return address from the kretprobe instance list. For this purpose this adds 'kr_cur' loop cursor to memorize the current kretprobe instance. With this fix, now arm64 can enable CONFIG_ARCH_CORRECT_STACKTRACE_ON_KRETPROBE, and pass the kprobe self tests. Signed-off-by: Masami Hiramatsu Acked-by: Will Deacon Signed-off-by: Steven Rostedt (VMware) --- arch/arm64/kernel/stacktrace.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch/arm64/kernel/stacktrace.c') diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 8982a2b78acf..c30624fff6ac 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -41,6 +41,9 @@ void start_backtrace(struct stackframe *frame, unsigned long fp, #ifdef CONFIG_FUNCTION_GRAPH_TRACER frame->graph = 0; #endif +#ifdef CONFIG_KRETPROBES + frame->kr_cur = NULL; +#endif /* * Prime the first unwind. @@ -129,6 +132,10 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame) frame->pc = ret_stack->ret; } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ +#ifdef CONFIG_KRETPROBES + if (is_kretprobe_trampoline(frame->pc)) + frame->pc = kretprobe_find_ret_addr(tsk, (void *)frame->fp, &frame->kr_cur); +#endif frame->pc = ptrauth_strip_insn_pac(frame->pc); -- cgit v1.2.3-59-g8ed1b