Re: [REGRESSION] v6.12.35: (build) kallsyms.h:21:10: fatal error: execinfo.h: No such file or directory

[Natanael Copa <ncopa@alpinelinux.org>]

On Tue, 1 Jul 2025 19:07:32 +0200
Sergio González Collado <sergio.collado@gmail.com> wrote:

> Hello,

Hi Sergio,

>  Thanks for pointing that out. I was not aware of it.

No worries. It happens. Just slightly unfortunate that it tickled down
to stable branches before it got fixed.

It is trivial to fix but I wonder what is the best way though. Achill
proposed to use #ifdef HAVE_BACKTRACE_SUPPORT in
tools/include/linux/kallsyms.h but it appears that this was included
only for KSYM_NAME_LEN.

KSYM_NAME_LEN appears to be defined multiple places:

$ rg 'KSYM_NAME_LEN\s+512'
include/linux/kallsyms.h
18:#define KSYM_NAME_LEN 512

tools/include/linux/kallsyms.h
9:#define KSYM_NAME_LEN 512

tools/lib/perf/include/perf/event.h
107:#define KSYM_NAME_LEN 512

tools/lib/symbol/kallsyms.h
10:#define KSYM_NAME_LEN 512

scripts/kallsyms.c
34:#define KSYM_NAME_LEN                512

So I wonder if it would be acceptable to simply:

diff --git a/arch/x86/tools/insn_decoder_test.c b/arch/x86/tools/insn_decoder_test.c
index 08cd913cbd4e..7916bf487ed2 100644
--- a/arch/x86/tools/insn_decoder_test.c
+++ b/arch/x86/tools/insn_decoder_test.c
@@ -10,7 +10,6 @@
 #include <assert.h>
 #include <unistd.h>
 #include <stdarg.h>
-#include <linux/kallsyms.h>
 
 #include <asm/insn.h>
 #include <inat.c>
@@ -105,6 +104,7 @@ static void parse_args(int argc, char **argv)
        }
 }
 
+#define KSYM_NAME_LEN 512
 #define BUFSIZE (256 + KSYM_NAME_LEN)
 
 int main(int argc, char **argv)

I am also confused with who should be in the CC list.

Thanks!
-nc
 
> On Tue, 1 Jul 2025 at 14:10, Natanael Copa <ncopa@alpinelinux.org> wrote:
> >
> > Hi!
> >
> > I bumped into a build regression when building Alpine Linux kernel 6.12.35 on x86_64:
> >
> > In file included from ../arch/x86/tools/insn_decoder_test.c:13:
> > ../tools/include/linux/kallsyms.h:21:10: fatal error: execinfo.h: No such file or directory
> >    21 | #include <execinfo.h>
> >       |          ^~~~~~~~~~~~
> > compilation terminated.
> >
> > The 6.12.34 kernel built just fine.
> >
> > I bisected it to:
> >
> > commit b8abcba6e4aec53868dfe44f97270fc4dee0df2a (HEAD)
> > Author: Sergio Gonz_lez Collado <sergio.collado@gmail.com>
> > Date:   Sun Mar 2 23:15:18 2025 +0100
> >
> >     Kunit to check the longest symbol length
> >
> >     commit c104c16073b7fdb3e4eae18f66f4009f6b073d6f upstream.
> >
> > which has this hunk:
> >
> > diff --git a/arch/x86/tools/insn_decoder_test.c b/arch/x86/tools/insn_decoder_test.c
> > index 472540aeabc2..6c2986d2ad11 100644
> > --- a/arch/x86/tools/insn_decoder_test.c
> > +++ b/arch/x86/tools/insn_decoder_test.c
> > @@ -10,6 +10,7 @@
> >  #include <assert.h>
> >  #include <unistd.h>
> >  #include <stdarg.h>
> > +#include <linux/kallsyms.h> 
> >
> >  #define unlikely(cond) (cond)
> >
> > @@ -106,7 +107,7 @@ static void parse_args(int argc, char **argv)
> >         }
> >  }
> >
> > -#define BUFSIZE 256
> > +#define BUFSIZE (256 + KSYM_NAME_LEN)
> >
> >  int main(int argc, char **argv)
> >  {
> >
> > It looks like the linux/kallsyms.h was included to get
> > KSYM_NAME_LEN. Unfortunately it also introduced the include of
> > execinfo.h, which does not exist on musl libc.
> >
> > This has previously been reported to and tried fixed:
> > https://lore.kernel.org/stable/DB0OSTC6N4TL.2NK75K2CWE9JV@pwned.life/T/#t
> >
> > Would it be an idea to revert commit b8abcba6e4ae til we have a
> > proper solution for this?
> >
> > Thanks!
> >
> > -nc