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| author | Masami Hiramatsu <mhiramat@kernel.org> | 2021-10-21 09:55:09 +0900 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2021-10-22 12:16:53 -0400 |
| commit | cd9bc2c9258816dc934b300705076519d7375b81 (patch) | |
| tree | 3be8beecf0c48ccece7a6f36a2c10ca19117753a | |
| parent | fc6d647638a8412800dfd10ad687709cb4aee373 (diff) | |
| download | lwn-cd9bc2c9258816dc934b300705076519d7375b81.tar.gz lwn-cd9bc2c9258816dc934b300705076519d7375b81.zip | |
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 <mhiramat@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| -rw-r--r-- | arch/arm64/Kconfig | 1 | ||||
| -rw-r--r-- | arch/arm64/include/asm/stacktrace.h | 4 | ||||
| -rw-r--r-- | arch/arm64/kernel/stacktrace.c | 7 |
3 files changed, 12 insertions, 0 deletions
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..a4e046ef4568 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 +60,9 @@ struct stackframe { #ifdef CONFIG_FUNCTION_GRAPH_TRACER int graph; #endif +#ifdef CONFIG_KRETPROBES + struct llist_node *kr_cur; +#endif }; 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..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); |