linux: Fix clock_getres fallback

The tst-timespec_getres (e5ac7bd679de5) triggers an issue on 32-bit
architecture on Linux older than 5.1, where the fallback syscall
is used.

Checked on powerpc-linux-gnu.

diff --git a/sysdeps/unix/sysv/linux/clock_getres.c b/sysdeps/unix/sysv/linux/clock_getres.c
index d560cd7..a9edec9 100644 (file)
--- a/sysdeps/unix/sysv/linux/clock_getres.c
+++ b/sysdeps/unix/sysv/linux/clock_getres.c
@@ -56,7 +56,7 @@ __clock_getres64 (clockid_t clock_id, struct __timespec64 *res)
 # else
   r = INLINE_SYSCALL_CALL (clock_getres, clock_id, &ts32);
 # endif
-  if (r == 0)
+  if (r == 0 && res != NULL)
     *res = valid_timespec_to_timespec64 (ts32);
 #endif