Re: [PATCH] selftests/vDSO: Fix undefined CLONE_NEWTIME by including

[Purva Yeshi]

On 27/01/25 13:32, Christophe Leroy wrote:
> Le 26/01/2025 à 11:59, Purva Yeshi a écrit :
> > [Vous ne recevez pas souvent de courriers de purvayeshi550@xxxxxxxxx. 
> > Découvrez pourquoi ceci est important à 
> > https://aka.ms/LearnAboutSenderIdentification ]
> >
> > Fix the build failure caused by the undefined `CLONE_NEWTIME`.
> > Include the `linux/sched.h` header file where the function is defined to
> > ensure successful compilation of the selftests.
>
> This is supposed to be already fixed by commit 34d5b600172b ("selftests: 
> vDSO: Explicitly include sched.h")
>
> Can you explain what is the exact problem still ? And why linux/sched.h ?

Yes, I noticed that sched.h is already included, but I still encountered 
an "undeclared CLONE_NEWTIME" error during compilation.

Error I got:
CC       vdso_test_getrandom
vdso_test_getrandom.c: In function ‘kselftest’:
vdso_test_getrandom.c:257:29: error: ‘CLONE_NEWTIME’ undeclared (first 
use in this function); did you mean ‘CLONE_NEWPID’?
  257 |         ksft_assert(unshare(CLONE_NEWTIME) == 0);
      |                             ^~~~~
vdso_test_getrandom.c:47:20: note: in definition of macro ‘ksft_assert’
   47 |         do { if (!(condition)) ksft_exit_fail_msg("Assertion 
failed: %s\n", #condition); } while (0)
      |                    ^~~~~
vdso_test_getrandom.c:257:29: note: each undeclared identifier is 
reported only once for each function it appears in
  257 |         ksft_assert(unshare(CLONE_NEWTIME) == 0);
      |                             ^~~~~
vdso_test_getrandom.c:47:20: note: in definition of macro ‘ksft_assert’
   47 |         do { if (!(condition)) ksft_exit_fail_msg("Assertion 
failed: %s\n", #condition); } while (0)
      |                    ^~~~~
make[1]: * [../lib.mk:222: 
/home/purva/linux/tools/testing/selftests/vDSO/vdso_test_getrandom] Error 1
make[1]: Leaving directory '/home/purva/linux/tools/testing/selftests/vDSO'

I found that CLONE_NEWTIME is declared in both sched.h and 
linux/sched.h. Since sched.h was already included, it was surprising 
that the error persisted. Adding linux/sched.h as a header resolved the 
issue, and the selftests compiled successfully after that.

> Did you properly build kernel headers before building selftests ?

Yes, I ensured that I properly built the kernel headers before building 
the selftests by following the documentation provided here 
(https://docs.kernel.org/dev-tools/kselftest.html#running-the-selftests-hotplug-tests-are-run-in-limited-mode). 
I used the 'make headers' command as part of the process.

> > Signed-off-by: Purva Yeshi <purvayeshi550@xxxxxxxxx>
> > ---
> >   tools/testing/selftests/vDSO/vdso_test_getrandom.c | 2 ++
> >   1 file changed, 2 insertions(+)
> >
> > diff --git a/tools/testing/selftests/vDSO/vdso_test_getrandom.c 
> > b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
> > index 95057f7567db..b2c9cf15878b 100644
> > --- a/tools/testing/selftests/vDSO/vdso_test_getrandom.c
> > +++ b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
> > @@ -29,6 +29,8 @@
> >   #include "vdso_config.h"
> >   #include "vdso_call.h"
> >
> > +#include <linux/sched.h>
> > +
> >   #ifndef timespecsub
> >   #define        timespecsub(tsp, usp, 
> > vsp)                                      \
> >          do 
> > {                                                            \
> > --
> > 2.34.1

Let me know if there’s anything further you'd like me to verify or adjust.

Thank you for your time and feedback!

Best regards,
Purva Yeshi