Re: [PATCH 1/3] tracing: Fix empty symbol names in simple_ring_buffer undef check

[Guenter Roeck <linux@roeck-us.net>]

On Wed, Sep 23, 2026 at 08:42:11AM +0100, Vincent Donnefort wrote:
> Sparc64 emits empty symmbol names. Skips them when establishing the
> allowlist and when extracing undefined symbols.
> 
> Fixes: 1211907ac0b5 ("tracing: Generate undef symbols allowlist for simple_ring_buffer")
> Reported-by: Guenter Roeck <linux@roeck-us.net>
> Closes: https://lore.kernel.org/all/5574c9e6-9ed2-4ee6-a2b2-fb6ee81e83a1@roeck-us.net/
> Signed-off-by: Vincent Donnefort <vdonnefort@google.com>

Tested-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  kernel/trace/Makefile | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
> index f934ff586bd4..0e1846f7dda3 100644
> --- a/kernel/trace/Makefile
> +++ b/kernel/trace/Makefile
> @@ -146,11 +146,11 @@ KASAN_SANITIZE_undefsyms_base.o := y
>  
>  UNDEFINED_ALLOWLIST = __asan __gcov __kasan __kcsan __hwasan __sancov __sanitizer __tsan __ubsan __msan \
>  		      __aeabi_unwind_cpp __s390_indirect_jump __x86_indirect_thunk simple_ring_buffer \
> -		      $(shell $(NM) -u $(obj)/undefsyms_base.o 2>/dev/null | awk '{print $$2}')
> +		      $(shell $(NM) -u $(obj)/undefsyms_base.o 2>/dev/null | awk '$$2 {print $$2}')
>  
>  quiet_cmd_check_undefined = NM      $<
>        cmd_check_undefined = \
> -          undefsyms=$$($(NM) -u $< | grep -v $(addprefix -e , $(UNDEFINED_ALLOWLIST)) || true); \
> +          undefsyms=$$($(NM) -u $< | awk '$$2 {print $$2}' | grep -v $(addprefix -e , $(UNDEFINED_ALLOWLIST)) || true); \
>            if [ -n "$$undefsyms" ]; then \
>                echo "Unexpected symbols in $<:" >&2; \
>                echo "$$undefsyms" >&2; \
> -- 
> 2.55.0.1082.g2b9226bbc0-goog
>