[PATCH 2/3] tracing: add more symbols to whitelist

[PATCH 2/3] tracing: add more symbols to whitelist

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

Randconfig builds show a number of cryptic build errors from
hitting undefined symbols in simple_ring_buffer.o:

make[7]: *** [/home/arnd/arm-soc/kernel/trace/Makefile:147: kernel/trace/simple_ring_buffer.o.checked] Error 1

These happen with CONFIG_TRACE_BRANCH_PROFILING, CONFIG_KASAN_HW_TAGS,
CONFIG_STACKPROTECTOR, CONFIG_DEBUG_IRQFLAGS and indirectly from WARN_ON().

Add exceptions for each one that I have hit so far on arm64, x86_64 and arm
randconfig builds.

Other architectures likely hit additional ones, so it would be nice
to produce a little more verbose output that include the name of the
missing symbols directly.

Fixes: a717943d8ecc ("tracing: Check for undefined symbols in simple_ring_buffer")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 kernel/trace/Makefile | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 3182e1bc1cf7..e3f8d6e619d2 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -138,6 +138,8 @@ obj-$(CONFIG_TRACE_REMOTE_TEST) += remote_test.o
 #
 UNDEFINED_ALLOWLIST := memset alt_cb_patch_nops __x86 __ubsan __asan __kasan __gcov __aeabi_unwind
 UNDEFINED_ALLOWLIST += __stack_chk_fail stackleak_track_stack __ref_stack __sanitizer
+UNDEFINED_ALLOWLIST += ftrace_likely_update __hwasan_load __hwasan_store __hwasan_tag_memory
+UNDEFINED_ALLOWLIST += warn_bogus_irq_restore warn_slowpath_fmt __stack_chk_guard
 UNDEFINED_ALLOWLIST := $(addprefix -e , $(UNDEFINED_ALLOWLIST))
 
 quiet_cmd_check_undefined = NM      $<
-- 
2.39.5

Re: [PATCH 2/3] tracing: add more symbols to whitelist

[Vincent Donnefort]

On Thu, Mar 12, 2026 at 01:35:43PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> Randconfig builds show a number of cryptic build errors from
> hitting undefined symbols in simple_ring_buffer.o:
> 
> make[7]: *** [/home/arnd/arm-soc/kernel/trace/Makefile:147: kernel/trace/simple_ring_buffer.o.checked] Error 1
> 
> These happen with CONFIG_TRACE_BRANCH_PROFILING, CONFIG_KASAN_HW_TAGS,
> CONFIG_STACKPROTECTOR, CONFIG_DEBUG_IRQFLAGS and indirectly from WARN_ON().
> 
> Add exceptions for each one that I have hit so far on arm64, x86_64 and arm
> randconfig builds.
> 
> Other architectures likely hit additional ones, so it would be nice
> to produce a little more verbose output that include the name of the
> missing symbols directly.
> 
> Fixes: a717943d8ecc ("tracing: Check for undefined symbols in simple_ring_buffer")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  kernel/trace/Makefile | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
> index 3182e1bc1cf7..e3f8d6e619d2 100644
> --- a/kernel/trace/Makefile
> +++ b/kernel/trace/Makefile
> @@ -138,6 +138,8 @@ obj-$(CONFIG_TRACE_REMOTE_TEST) += remote_test.o
>  #
>  UNDEFINED_ALLOWLIST := memset alt_cb_patch_nops __x86 __ubsan __asan __kasan __gcov __aeabi_unwind
>  UNDEFINED_ALLOWLIST += __stack_chk_fail stackleak_track_stack __ref_stack __sanitizer
> +UNDEFINED_ALLOWLIST += ftrace_likely_update __hwasan_load __hwasan_store __hwasan_tag_memory
> +UNDEFINED_ALLOWLIST += warn_bogus_irq_restore warn_slowpath_fmt __stack_chk_guard
>  UNDEFINED_ALLOWLIST := $(addprefix -e , $(UNDEFINED_ALLOWLIST))
>  
>  quiet_cmd_check_undefined = NM      $<
> -- 
> 2.39.5
> 

Thanks for the patch.

Most of those ones are covered here
https://lore.kernel.org/all/20260312113535.2213350-1-vdonnefort@google.com/.

This should fix allmodconfig.

For the ones not covered, I'm working on a follow-up patch using a different
approach which should fix them. I'll be able to share it today or tomorrow. Not
sure if we want to take this temporarily?

Re: [PATCH 2/3] tracing: add more symbols to whitelist

[Arnd Bergmann]

On Thu, Mar 12, 2026, at 14:40, Vincent Donnefort wrote:
> On Thu, Mar 12, 2026 at 01:35:43PM +0100, Arnd Bergmann wrote:
>> diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile

>> +UNDEFINED_ALLOWLIST += ftrace_likely_update __hwasan_load __hwasan_store __hwasan_tag_memory
>> +UNDEFINED_ALLOWLIST += warn_bogus_irq_restore warn_slowpath_fmt __stack_chk_guard
 
>
> Thanks for the patch.
>
> Most of those ones are covered here
> https://lore.kernel.org/all/20260312113535.2213350-1-vdonnefort@google.com/.
>
> This should fix allmodconfig.

The ones I see in that patch look entirely different from the ones
I found.

> For the ones not covered, I'm working on a follow-up patch using a different
> approach which should fix them. I'll be able to share it today or tomorrow. Not
> sure if we want to take this temporarily?

I can wait, my randconfig setup has my patch applied locally for now,
but I've only fixed the ones I saw on three architectures with gcc-16.0.1,
while Nathan's list seems to be mostly for clang specific symbols.

A lot of them also don't show up in allmodconfig builds, only after a
larger number of randconfig configurations.

      Arnd

Re: [PATCH 2/3] tracing: add more symbols to whitelist

[Marc Zyngier]

On Thu, 12 Mar 2026 14:37:50 +0000,
"Arnd Bergmann" <arnd@arndb.de> wrote:
> 
> On Thu, Mar 12, 2026, at 14:40, Vincent Donnefort wrote:
> > On Thu, Mar 12, 2026 at 01:35:43PM +0100, Arnd Bergmann wrote:
> >> diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
> 
> >> +UNDEFINED_ALLOWLIST += ftrace_likely_update __hwasan_load __hwasan_store __hwasan_tag_memory
> >> +UNDEFINED_ALLOWLIST += warn_bogus_irq_restore warn_slowpath_fmt __stack_chk_guard
>  
> >
> > Thanks for the patch.
> >
> > Most of those ones are covered here
> > https://lore.kernel.org/all/20260312113535.2213350-1-vdonnefort@google.com/.
> >
> > This should fix allmodconfig.
> 
> The ones I see in that patch look entirely different from the ones
> I found.
> 
> > For the ones not covered, I'm working on a follow-up patch using a different
> > approach which should fix them. I'll be able to share it today or tomorrow. Not
> > sure if we want to take this temporarily?
> 
> I can wait, my randconfig setup has my patch applied locally for now,
> but I've only fixed the ones I saw on three architectures with gcc-16.0.1,
> while Nathan's list seems to be mostly for clang specific symbols.
> 
> A lot of them also don't show up in allmodconfig builds, only after a
> larger number of randconfig configurations.

I've decided to take this patch anyway, on top of Vincent's. Should a
more generic solution arise, I can always drop both.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

Re: [PATCH 2/3] tracing: add more symbols to whitelist

[Arnd Bergmann]

On Thu, Mar 12, 2026, at 16:21, Marc Zyngier wrote:
>
> I've decided to take this patch anyway, on top of Vincent's. Should a
> more generic solution arise, I can always drop both.
>

Ok, thanks!

FWIW, I came across two additional ones by now, and will keep
running more tests to see what else comes up:

--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -140,6 +140,7 @@ UNDEFINED_ALLOWLIST := memset alt_cb_patch_nops __x86 __ubsan __asan __kasan __g
 UNDEFINED_ALLOWLIST += __stack_chk_fail stackleak_track_stack __ref_stack __sanitizer
 UNDEFINED_ALLOWLIST += ftrace_likely_update __hwasan_load __hwasan_store __hwasan_tag_memory
 UNDEFINED_ALLOWLIST += warn_bogus_irq_restore warn_slowpath_fmt __stack_chk_guard
+UNDEFINED_ALLOWLIST += __kcsan __tsan
 UNDEFINED_ALLOWLIST := $(addprefix -e , $(UNDEFINED_ALLOWLIST))
 
 quiet_cmd_check_undefined = NM      $<


      Arnd