[glibc] tst-process_madvise: Check process_madvise-syscall support.

[Stefan Liebler <stli@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=11f09947f3066f5ff84fd15ef22b72b46eea97a8

commit 11f09947f3066f5ff84fd15ef22b72b46eea97a8
Author: Stefan Liebler <stli@linux.ibm.com>
Date:   Thu Aug 11 09:47:46 2022 +0200

    tst-process_madvise: Check process_madvise-syscall support.
    
    So far this test checks if pidfd_open-syscall is supported,
    which was introduced with linux 5.3.
    
    The process_madvise-syscall was introduced with linux 5.10.
    Thus you'll get FAILs if you are running a kernel in between.
    
    This patch adds a check if the first process_madvise-syscall
    returns ENOSYS and in this case will fail with UNSUPPORTED.
    Reviewed-by: Florian Weimer <fweimer@redhat.com>

Diff:
---
 sysdeps/unix/sysv/linux/tst-process_madvise.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/sysdeps/unix/sysv/linux/tst-process_madvise.c b/sysdeps/unix/sysv/linux/tst-process_madvise.c
index a674e80b76..3b032ddefc 100644
--- a/sysdeps/unix/sysv/linux/tst-process_madvise.c
+++ b/sysdeps/unix/sysv/linux/tst-process_madvise.c
@@ -101,8 +101,11 @@ do_test (void)
 
     /* We expect this to succeed in the target process because the mapping
        is valid.  */
-    TEST_COMPARE (process_madvise (pidfd, &iv, 1, MADV_COLD, 0),
-		  2 * page_size);
+    ssize_t ret = process_madvise (pidfd, &iv, 1, MADV_COLD, 0);
+    if (ret == -1 && errno == ENOSYS)
+      FAIL_UNSUPPORTED ("kernel does not support process_madvise, skipping"
+			"test");
+    TEST_COMPARE (ret, 2 * page_size);
   }
 
   {