Re: [PATCH] KVM: selftests: Guard execinfo.h inclusion for non-glibc builds

[Shuah Khan <skhan@linuxfoundation.org>]

On 3/24/26 12:02, Shuah Khan wrote:
> On 3/18/26 18:08, Hisam Mehboob wrote:
>> The backtrace() function and execinfo.h are GNU extensions available
>> in glibc but not in non-glibc C libraries such as musl. Building KVM
>> selftests with musl-gcc fails with:
>>
>>    lib/assert.c:9:10: fatal error: execinfo.h: No such file or directory
>>
>> Guard the inclusion of execinfo.h under #ifdef __GLIBC__, and wrap
>> all backtrace() usage under the same guard with a fallback message
>> for non-glibc builds indicating that stack traces are not available.
>>
>> Unlike the approach of adding a weak stub for backtrace(), this
>> explicitly handles the non-glibc case rather than silently providing
>> an empty implementation.
>>
>> Link: https://lore.kernel.org/kvm/20250829142556.72577-7-aqibaf@amazon.com/
>>
>> Suggested-by: Aqib Faruqui <aqibaf@amazon.com>
>> Signed-off-by: Hisam Mehboob <hisamshar@gmail.com>
>> ---
>>   tools/testing/selftests/kvm/lib/assert.c | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/tools/testing/selftests/kvm/lib/assert.c b/tools/testing/selftests/kvm/lib/assert.c
>> index b49690658c60..3442b80c37c1 100644
>> --- a/tools/testing/selftests/kvm/lib/assert.c
>> +++ b/tools/testing/selftests/kvm/lib/assert.c
>> @@ -6,7 +6,9 @@
>>    */
>>   #include "test_util.h"
>> +#ifdef __GLIBC__
>>   #include <execinfo.h>
>> +#endif
> > Is __GLIBC__ defined in musl-gcc? Looks like that is the case with the
> error?

If __GLIBC__ isn't there you shouldn't see this error because the include
is in - this error doesn't make sense if __GLIBC__ isn't defined. What
am I missing?

+#ifdef __GLIBC__
  #include <execinfo.h>
+#endif

Also check tools/testing/selftests/bpf/test_progs.c - I think backtrace()
stub needs be defined only for the !__GLIBC__ case

thanks,
-- Shuah