kallsyms: fix build without execinfo

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.

Link: https://lkml.kernel.org/r/20250622014608.448718-1-fossdd@pwned.life
Fixes: c104c16073b7 ("Kunit to check the longest symbol length")
Signed-off-by: Achill Gilgenast <fossdd@pwned.life>
Cc: Luis Henriques <luis@igalia.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/tools/include/linux/kallsyms.h b/tools/include/linux/kallsyms.h
index 5a37ccbec54fbc603108ad9346c0351c8a3c56a8..f61a01dd7eb7c7833a335c21b660c0c9332bbeff 100644 (file)
--- 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)
@@ -30,5 +31,8 @@ static inline void print_ip_sym(const char *loglvl, unsigned long ip)
 
        free(name);
 }
+#else
+static inline void print_ip_sym(const char *loglvl, unsigned long ip) {}
+#endif
 
 #endif