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authorMark Rutland <mark.rutland@arm.com>2023-04-11 17:29:41 +0100
committerWill Deacon <will@kernel.org>2023-04-11 18:34:59 +0100
commit9e09d445f1cab518eedf4454d119ead27979b8f4 (patch)
treee48a5ada92073bdab4e6d2003f673c16756fdacf /arch/arm64/kernel
parente8d018dd0257f744ca50a729e3d042cf2ec9da65 (diff)
arm64: stacktrace: recover return address for first entry
The function which calls the top-level backtracing function may have been instrumented with ftrace and/or kprobes, and hence the first return address may have been rewritten. Factor out the existing fgraph / kretprobes address recovery, and use this for the first address. As the comment for the fgraph case isn't all that helpful, I've also dropped that. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Kalesh Singh <kaleshsingh@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> Cc: Mark Brown <broonie@kernel.org> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20230411162943.203199-2-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/kernel')
-rw-r--r--arch/arm64/kernel/stacktrace.c53
1 files changed, 30 insertions, 23 deletions
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 83154303e682..dd03feba8048 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -69,6 +69,32 @@ static __always_inline void unwind_init_from_task(struct unwind_state *state,
state->pc = thread_saved_pc(task);
}
+static __always_inline int
+unwind_recover_return_address(struct unwind_state *state)
+{
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ if (state->task->ret_stack &&
+ (state->pc == (unsigned long)return_to_handler)) {
+ unsigned long orig_pc;
+ orig_pc = ftrace_graph_ret_addr(state->task, NULL, state->pc,
+ (void *)state->fp);
+ if (WARN_ON_ONCE(state->pc == orig_pc))
+ return -EINVAL;
+ state->pc = orig_pc;
+ }
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+#ifdef CONFIG_KRETPROBES
+ if (is_kretprobe_trampoline(state->pc)) {
+ state->pc = kretprobe_find_ret_addr(state->task,
+ (void *)state->fp,
+ &state->kr_cur);
+ }
+#endif /* CONFIG_KRETPROBES */
+
+ return 0;
+}
+
/*
* Unwind from one frame record (A) to the next frame record (B).
*
@@ -92,35 +118,16 @@ static int notrace unwind_next(struct unwind_state *state)
state->pc = ptrauth_strip_insn_pac(state->pc);
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- if (tsk->ret_stack &&
- (state->pc == (unsigned long)return_to_handler)) {
- unsigned long orig_pc;
- /*
- * This is a case where function graph tracer has
- * modified a return address (LR) in a stack frame
- * to hook a function return.
- * So replace it to an original value.
- */
- orig_pc = ftrace_graph_ret_addr(tsk, NULL, state->pc,
- (void *)state->fp);
- if (WARN_ON_ONCE(state->pc == orig_pc))
- return -EINVAL;
- state->pc = orig_pc;
- }
-#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
-#ifdef CONFIG_KRETPROBES
- if (is_kretprobe_trampoline(state->pc))
- state->pc = kretprobe_find_ret_addr(tsk, (void *)state->fp, &state->kr_cur);
-#endif
-
- return 0;
+ return unwind_recover_return_address(state);
}
NOKPROBE_SYMBOL(unwind_next);
static void notrace unwind(struct unwind_state *state,
stack_trace_consume_fn consume_entry, void *cookie)
{
+ if (unwind_recover_return_address(state))
+ return;
+
while (1) {
int ret;