[PATCH] Linux: Do not check unused bytes after sched_getattr in tst-sched_setattr

[Florian Weimer]

Linux 6.13 was released with a change that overwrites those bytes.
This means that the check_unused subtest fails.

Update the manual accordingly.

Tested on x86_64-linux-gnu (although not with Linux 6.13).

---
 manual/resource.texi                        |  6 +++---
 sysdeps/unix/sysv/linux/tst-sched_setattr.c | 11 -----------
 2 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/manual/resource.texi b/manual/resource.texi
index 612520d4d9..0b82446817 100644
--- a/manual/resource.texi
+++ b/manual/resource.texi
@@ -1058,9 +1058,9 @@ available in the future.
 
 Upon success, @code{@var{attr}->size} contains the size of the structure
 version used by the kernel.  Fields with offsets greater or equal to
-@code{@var{attr}->size} are not updated by the kernel.  To obtain
-predictable values for unknown fields, use @code{memset} to set
-all @var{size} bytes to zero prior to calling @code{sched_getattr}.
+@code{@var{attr}->size} may not be overwritten by the kernel.  To obtain
+predictable values for unknown fields, use @code{memset} to set all
+@var{size} bytes to zero prior to calling @code{sched_getattr}.
 
 On failure, @code{sched_getattr} returns @math{-1} and sets @code{errno}.
 If @code{errno} is @code{E2BIG}, this means that the buffer is not large
diff --git a/sysdeps/unix/sysv/linux/tst-sched_setattr.c b/sysdeps/unix/sysv/linux/tst-sched_setattr.c
index ebad0ae2a8..bf8d9afd34 100644
--- a/sysdeps/unix/sysv/linux/tst-sched_setattr.c
+++ b/sysdeps/unix/sysv/linux/tst-sched_setattr.c
@@ -33,14 +33,6 @@ union
   unsigned char padding[4096];
 } u;
 
-static void
-check_unused (void)
-{
-  TEST_VERIFY (u.attr.size < sizeof (u));
-  for (unsigned int i = u.attr.size; i < sizeof (u); ++i)
-    TEST_COMPARE (u.padding[i], 0xcc);
-}
-
 static int
 do_test (void)
 {
@@ -53,7 +45,6 @@ do_test (void)
   /* Compiler barrier to bypass write access attribute.  */
   volatile unsigned int size = sizeof (u);
   TEST_COMPARE (sched_getattr (0, (struct sched_attr *) &u, size, 0), 0);
-  check_unused ();
   TEST_COMPARE (sched_setattr (0, &u.attr, 0), 0); /* Apply unchanged.  */
 
   /* Try to switch to the SCHED_OTHER policy.   */
@@ -81,14 +72,12 @@ do_test (void)
   memset (&u, 0xcc, sizeof (u));
   TEST_COMPARE (sched_getattr (0, (struct sched_attr *) &u, size, 0), 0);
   TEST_COMPARE (u.attr.sched_policy, SCHED_OTHER);
-  check_unused ();
 
   /* Raise the niceless level to 19 and observe its effect.  */
   TEST_COMPARE (nice (19), 19);
   TEST_COMPARE (sched_getattr (0, &u.attr, sizeof (u.attr), 0), 0);
   TEST_COMPARE (u.attr.sched_policy, SCHED_OTHER);
   TEST_COMPARE (u.attr.sched_nice, 19);
-  check_unused ();
 
   /* Invalid buffer arguments result in EINVAL (not EFAULT).  */
   {

base-commit: 8ef17919509e909746b0ad6465e9c6c952a3fe34