Re: [RESEND PATCH v2] kallsyms: fix build without execinfo

[Luis Henriques <luis@igalia.com>]

On Tue, Jul 01 2025, Achill Gilgenast wrote:

> On Mon Jun 23, 2025 at 1:53 PM CEST, Achill Gilgenast wrote:
>> On Sun Jun 22, 2025 at 8:36 PM CEST, Andrew Morton wrote:
>>> On Sun, 22 Jun 2025 03:45:49 +0200 Achill Gilgenast <fossdd@pwned.life> wrote:
>>>
>>>> Some libc's like musl libc don't provide execinfo.h since it's not part
>>>> of POSIX. In order to fix compilation on musl, only include execinfo.h
>>>> if available (HAVE_BACKTRACE_SUPPORT)
>>>> 
>>>> This was discovered with c104c16073b7 ("Kunit to check the longest symbol length")
>>>> which starts to include linux/kallsyms.h with Alpine Linux' configs.
>>>> 
>>>> ...
>>>>
>>>> --- a/tools/include/linux/kallsyms.h
>>>> +++ b/tools/include/linux/kallsyms.h
>>>> @@ -18,6 +18,7 @@ static inline const char *kallsyms_lookup(unsigned long addr,
>>>>  	return NULL;
>>>>  }
>>>>  
>>>> +#ifdef HAVE_BACKTRACE_SUPPORT
>>>>  #include <execinfo.h>
>>>>  #include <stdlib.h>
>>>>  static inline void print_ip_sym(const char *loglvl, unsigned long ip)
>>>
>>> I'm not seeing anything in there which needs execinfo.h.  Can we simply
>>> remove the inclusion?
>>
>> No, since backtrace_symbols is provided by execinfo.h.
>
> Is there some status on it? I saw you picked it in mm-hotfixes-unstable,
> but it got dropped out again.
>
> Is there something I can do to push it?

FWIW I can confirm this is indeed a regression.  And specially annoying
because it has been backported into stable kernels (even if having kunit
tests backported sounds odd to me).

It would be great to have this fixed, or reverted.

Cheers,
-- 
Luís