On Wed, Jul 15, 2026 at 09:38:21AM +0200, Arnd Bergmann wrote: > On Tue, Jul 14, 2026, at 23:56, Steven Rostedt wrote: > > On Wed, 17 Jun 2026 14:26:36 +0100 Vincent Donnefort > > <[email protected]> wrote: > > > >> On Tue, Jun 16, 2026 at 06:42:03PM +0200, Arnd Bergmann wrote: > >> > From: Arnd Bergmann <[email protected]> > >> > > >> > In randconfig build testing using clang-22, I came across two > >> > sets of extra symbols in the ring buffer code that may get > >> > inserted by the compiler: > >> > > >> > Unexpected symbols in kernel/trace/simple_ring_buffer.o: > >> > U memset > >> > > >> > Unexpected symbols in kernel/trace/simple_ring_buffer.o: > >> > U llvm_gcda_emit_arcs > >> > U llvm_gcda_emit_function > >> > U llvm_gcda_end_file > >> > U llvm_gcda_start_file > >> > U llvm_gcda_summary_info > >> > U llvm_gcov_init > >> > > >> > Add all of these to the allowlist. > >> > > >> > Signed-off-by: Arnd Bergmann <[email protected]> > >> > --- > >> > kernel/trace/Makefile | 1 + > >> > 1 file changed, 1 insertion(+) > >> > > >> > diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile > >> > index f934ff586bd4..aa8564fb8ff4 100644 > >> > --- a/kernel/trace/Makefile > >> > +++ b/kernel/trace/Makefile > >> > @@ -146,6 +146,7 @@ KASAN_SANITIZE_undefsyms_base.o := y > >> > >> Would "GCOV_PROFILE_undefsyms_base.o := y" work? > > > > Arnd? > > Yes, turning off gcov for this file should avoid the llvm_gcda and > llvm_gcov symbols, but not the memset() symbol.
This would actually turn on GCOV for this translation unit and cause the llvm_gcda and llvm_gcov symbols to be included in UNDEFINED_ALLOWLIST via the $(NM) call. > All the other features that leave annotations are handled by > listing the symbol names (__asan __gcov __kasan __kcsan __hwasan > __sancov __sanitizer __tsan __ubsan __msan), so I think for > consistency it makes sense to treat llvm gcov the same way > we handle gcc gcov and the rest. I do tend to agree with this though, as opposed to using GCOV_PROFILE_... or ..._SANTIZE variables. -- Cheers, Nathan
