On 05/09/2025 19:02, Mark Brown wrote:

On Fri, Sep 05, 2025 at 01:55:53PM -0400, Zi Yan wrote:

quoted

On 5 Sep 2025, at 13:43, Mark Brown wrote:

quoted

quoted

but the header there is getting ignored AFAICT.  Probably the problem is
fairly obvious and I'm just being slow - I'm not quite 100% at the
minute.

quoted

prctl_thp_disable.c uses “#include <sys/mman.h>” but asm-generic/mman-common.h
is included in asm/mman.h. And sys/mman.h gets MADV_COLLAPSE from
bits/mman-linux.h. Maybe that is why?

Ah, of course - if glibc is reproducing the kernel definitions rather
than including the kernel headers to get them then that'd do it.
Probably the test needs to locally define the new MADV_COLLAPSE for
glibc compatibility, IME trying to directly include the kernel headers
when glibc doesn't normally use them tends to blow up on you sooner or
later.

I knew it'd be something simple, thanks.

Hi Mark,

Thanks for raising this. I think doing 

diff --git a/tools/testing/selftests/mm/prctl_thp_disable.c b/tools/testing/selftests/mm/prctl_thp_disable.c
index 89ed0d7db1c16..0afcdbad94f3d 100644
--- a/tools/testing/selftests/mm/prctl_thp_disable.c
+++ b/tools/testing/selftests/mm/prctl_thp_disable.c

@@ -9,6 +9,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <sys/mman.h>
+#include <linux/mman.h>
 #include <sys/prctl.h>
 #include <sys/wait.h>

should fix this issue?

Thanks
Usama