Re: [RFC PATCH 07/13] stacktrace: export stack_trace_save_regs()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The patch exports `stack_trace_save_regs` so it can be used by modules, but fails to update the in-tree kprobes sanity test which contains a workaround specifically because the symbol was previously unexported. Leaving the workaround artificially reduces test coverage for module builds.
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--- Patch [7]: [RFC PATCH 07/13] stacktrace: export stack_trace_save_regs() ---
commit 594dee655bf56c8a9f1858d2d50ddbf441315c12
Author: Jinchao Wang <wangjinchao600@gmail.com>

stacktrace: export stack_trace_save_regs()

The other stack_trace_save_*() flavours are exported, but the regs
variant is not, so no module can capture a stack trace for a given
pt_regs. KWatch, which may be built as a module, uses it. Export it like
its siblings.

> diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
> index afb3c116da91a..d853c40f916b2 100644
> --- a/kernel/stacktrace.c
> +++ b/kernel/stacktrace.c
> @@ -175,6 +175,7 @@ unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
>  	arch_stack_walk(consume_entry, &c, current, regs);
>  	return c.len;
>  }
> +EXPORT_SYMBOL_GPL(stack_trace_save_regs);

[Severity: Medium]
Since stack_trace_save_regs() is now exported for modules, should we also
update the kprobes sanity test to remove the workarounds that skip testing
this function when built as a module?

In lib/tests/test_kprobes.c:stacktrace_return_handler():

#if !IS_MODULE(CONFIG_KPROBES_SANITY_TEST)
	/*
	 * Test stacktrace from pt_regs at the return address. Thus the stack
	 * trace must start from the target return address.
	 */
	ret = stack_trace_save_regs(regs, stack_buf, STACK_BUF_SIZE, 0);

And similarly in lib/tests/test_kprobes.c:stacktrace_internal_return_handler():

#if !IS_MODULE(CONFIG_KPROBES_SANITY_TEST)
	/* Ditto for the regs version. */
	ret = stack_trace_save_regs(regs, stack_buf, STACK_BUF_SIZE, 0);

Removing these checks would restore test coverage for module builds now that
the symbol is available.

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Sashiko AI review · https://sashiko.dev/#/patchset/20260714182243.10687-1-wangjinchao600@gmail.com?part=7