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

[Natanael Copa <ncopa@alpinelinux.org>]

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