From fed240d9c9743815fcbc0ca5c0913292ce1f25e2 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 21 Oct 2021 09:55:35 +0900 Subject: ARM: Recover kretprobe modified return address in stacktrace Since the kretprobe replaces the function return address with the kretprobe_trampoline on the stack, arm unwinder shows it instead of the correct return address. This finds the correct return address from the per-task kretprobe_instances list and verify it is in between the caller fp and callee fp. Note that this supports both GCC and clang if CONFIG_FRAME_POINTER=y and CONFIG_ARM_UNWIND=n. For the ARM unwinder, this is still not working correctly. Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- arch/arm/kernel/stacktrace.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'arch/arm/kernel/stacktrace.c') diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c index db798eac7431..75e905508f27 100644 --- a/arch/arm/kernel/stacktrace.c +++ b/arch/arm/kernel/stacktrace.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0-only #include +#include #include #include #include @@ -65,6 +66,11 @@ int notrace unwind_frame(struct stackframe *frame) frame->sp = *(unsigned long *)(fp - 8); frame->pc = *(unsigned long *)(fp - 4); #endif +#ifdef CONFIG_KRETPROBES + if (is_kretprobe_trampoline(frame->pc)) + frame->pc = kretprobe_find_ret_addr(frame->tsk, + (void *)frame->fp, &frame->kr_cur); +#endif return 0; } @@ -156,6 +162,10 @@ static noinline void __save_stack_trace(struct task_struct *tsk, frame.lr = (unsigned long)__builtin_return_address(0); frame.pc = (unsigned long)__save_stack_trace; } +#ifdef CONFIG_KRETPROBES + frame.kr_cur = NULL; + frame.tsk = tsk; +#endif walk_stackframe(&frame, save_trace, &data); } @@ -173,6 +183,10 @@ void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace) frame.sp = regs->ARM_sp; frame.lr = regs->ARM_lr; frame.pc = regs->ARM_pc; +#ifdef CONFIG_KRETPROBES + frame.kr_cur = NULL; + frame.tsk = current; +#endif walk_stackframe(&frame, save_trace, &data); } -- cgit