On 2026-06-23 11:01, Bruno Haible wrote:
Yesterday's CI of GNU m4 (newest m4 sources, newest gnulib sources, on
Alpine Linux) shows a test failure:
FAIL: test-fstatat
==================
Segmentation fault (core dumped)
FAIL test-fstatat (exit status: 139)
I reproduce it in Alpine Linux 3.24.1 (but not in 3.22 nor 3.20).
Thanks for the bug report. Unfortunately portal.cfarm.net lists only
Alpine 3.22 and 3.23.
Was this a crosscompile, or native? Was it x86-64 or some other
platform? Is the build log public?
The backtrace is:
test-fstatat.c:111
-> musl/src/stat/fstatat.c:147
-> musl/src/stat/fstatat.c:81
That line reads:
if (flag==AT_EMPTY_PATH && fd>=0 && !*path) {
The backtrace suggests that REPLACE_FSTATAT was 0, because there is no
rentry for Gnulib's lib/fstatat.c. However, REPLACE_FSTATAT should have
been 1 because the musl source code doesn't support AT_EMPTY_PATH with a
null pointer .
Can you verify whether fstatat is being replaced by checking that
m4/lib/sys/stat.h contains lines like the following?
#if 1
# if 1
# if !(defined __cplusplus && defined GNULIB_NAMESPACE)
# undef fstatat
# define fstatat rpl_fstatat
# endif
_GL_FUNCDECL_RPL (fstatat, int,
Can you look in config.log for lines like the following?
... checking whether fstatat+AT_EMPTY_PATH allows null file
...
... result: yes
What happens when you compile and run the following program? What's the
tail of "strace ./a.out"? (This is the program 'configure' should be
running to see whether AT_EMPTY_PATH works with a null pointer.)
#include <stddef.h>
#include <fcntl.h>
#include <sys/stat.h>
#ifndef AT_EMPTY_PATH
# define AT_EMPTY_PATH 0
#endif
#if __GLIBC__ && ! (2 < __GLIBC__ + (41 <= __GLIBC_MINOR__))
#error "glibc 2.40 and earlier can fail with null file"
#endif
int
main (void)
{
struct stat st;
return
(AT_EMPTY_PATH
&& fstatat (AT_FDCWD, NULL, &st, AT_EMPTY_PATH) < 0);
}
What is the output of the shell command 'nm -g lib/libm4_a-fstatat.o'?
Your bug report prompted me to update GNU m4's Gnulib to the current
version, and fix some glitches I noticed on Fedora 44. But I don't think
this fixed your bug.
