Messages in this thread Patch in this message | | | From | Masami Hiramatsu <> | Subject | [PATCH 5/8] arm64: Recover kretprobe modified return address in stacktrace | Date | Fri, 8 Oct 2021 21:28:58 +0900 |
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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.
With this fix, now arm64 can enable CONFIG_ARCH_CORRECT_STACKTRACE_ON_KRETPROBE, and pass the kprobe self tests.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/stacktrace.h | 2 ++ arch/arm64/kernel/stacktrace.c | 3 +++ 3 files changed, 6 insertions(+)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 5c7ae4c3954b..edde5171ffb2 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -11,6 +11,7 @@ config ARM64 select ACPI_PPTT if ACPI select ARCH_HAS_DEBUG_WX select ARCH_BINFMT_ELF_STATE + select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION select ARCH_ENABLE_MEMORY_HOTPLUG select ARCH_ENABLE_MEMORY_HOTREMOVE diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h index 8aebc00c1718..8f997a602651 100644 --- a/arch/arm64/include/asm/stacktrace.h +++ b/arch/arm64/include/asm/stacktrace.h @@ -9,6 +9,7 @@ #include <linux/sched.h> #include <linux/sched/task_stack.h> #include <linux/types.h> +#include <linux/llist.h> #include <asm/memory.h> #include <asm/ptrace.h> @@ -59,6 +60,7 @@ struct stackframe { #ifdef CONFIG_FUNCTION_GRAPH_TRACER int graph; #endif + struct llist_node *kr_cur; }; extern int unwind_frame(struct task_struct *tsk, struct stackframe *frame); diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 8982a2b78acf..f1eef5745542 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -129,6 +129,8 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame) frame->pc = ret_stack->ret; } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + if (is_kretprobe_trampoline(frame->pc)) + frame->pc = kretprobe_find_ret_addr(tsk, (void *)frame->fp, &frame->kr_cur); frame->pc = ptrauth_strip_insn_pac(frame->pc); @@ -224,6 +226,7 @@ noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry, { struct stackframe frame; + memset(&frame, 0, sizeof(frame)); if (regs) start_backtrace(&frame, regs->regs[29], regs->pc); else if (task == current)
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