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arm64: stacktrace: recover return address for first entry

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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>
This commit is contained in:
Mark Rutland 2023-04-11 17:29:41 +01:00 committed by Will Deacon
parent e8d018dd02
commit 9e09d445f1
1 changed files with 30 additions and 23 deletions
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53
arch/arm64/kernel/stacktrace.c
View File

@ -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;