[PATCH 2/2] riscv: Add KUnit test for stack trace start frames

[Shuai Xue]

On 10/10/26 9:27 PM, Karl Mehltretter wrote:
> stack_trace_save() and return_address() depend on the first frame reported
> by arch_stack_walk(), but no test checks their frame numbering.
> 
> Add a test that calls both through a chain of three noinline functions
> and compares the symbol of the result with the function expected for
> each skip count or level.
> 
> Require FRAME_POINTER because the stack-scanning walker cannot provide an
> exact start frame.
> 
> Assisted-by: LLM
> Signed-off-by: Karl Mehltretter <kmehltretter at gmail.com>
> ---
>   arch/riscv/kernel/tests/Kconfig.debug     |  12 ++
>   arch/riscv/kernel/tests/Makefile          |   1 +
>   arch/riscv/kernel/tests/stacktrace_test.c | 142 ++++++++++++++++++++++
>   3 files changed, 155 insertions(+)
> 
> diff --git a/arch/riscv/kernel/tests/Kconfig.debug b/arch/riscv/kernel/tests/Kconfig.debug
> index 40f8dafffa0a..eb79df5b2c5a 100644
> --- a/arch/riscv/kernel/tests/Kconfig.debug
> +++ b/arch/riscv/kernel/tests/Kconfig.debug
> @@ -42,6 +42,18 @@ config RISCV_KPROBES_KUNIT
>   
>            If unsure, say N.
>   
> +config RISCV_STACKTRACE_KUNIT_TEST
> +	bool "KUnit tests for RISC-V stack trace start frames"
> +	depends on KUNIT && STACKTRACE && FRAME_POINTER && KALLSYMS

Hi, Karl

One small nit: the new RISCV_STACKTRACE_KUNIT_TEST entry does
not follow the KUNIT_ALL_TESTS pattern of the two existing entries
right next to it (RISCV_KPROBES_KUNIT, RISCV_MODULE_LINKING_KUNIT):

     config RISCV_STACKTRACE_KUNIT_TEST
             bool "KUnit tests for RISC-V stack trace start frames" if !KUNIT_ALL_TESTS
             default KUNIT_ALL_TESTS

Without "default KUNIT_ALL_TESTS" the suite is never enabled by
kunit.all_tests, and without the "if !KUNIT_ALL_TESTS" prompt guard
it shows up as a redundant prompt when KUNIT_ALL_TESTS is already
set.  This is not a blocker in any way, just a nice tweak for a
potential v2.

Please feel free to add

     Tested-by: Shuai Xue <xueshuai at linux.alibaba.com>

to both patches, and additionally on 1/2

     Reviewed-by: Shuai Xue <xueshuai at linux.alibaba.com>

Thanks!
Shuai