On 30/01/25 12:32, Christophe Leroy wrote:
Le 29/01/2025 à 19:17, Purva Yeshi a écrit :
On 27/01/25 13:32, Christophe Leroy wrote:
Le 26/01/2025 à 11:59, Purva Yeshi a écrit :
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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.
Must be that your sched.h is not up-to-date I guess. On my side I have:
/usr/include/linux/sched.h:#define CLONE_NEWTIME 0x00000080 /* New
time namespace */
/usr/include/bits/sched.h:#define CLONE_NEWTIME 0x00000080 /*
New time namespace */
And
/usr/include/sched.h:#include <bits/sched.h>
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.
Can you recheck that the sched.h that contains CLONE_NEWTIME is really
the one used by your compiler ?
I rechecked the header files on my system and got the following output:
purva@purva-IdeaPad-Gaming-3-15IHU6:~/linux$ grep -r "CLONE_NEWTIME"
/usr/include/linux/sched.h /usr/include/bits/sched.h /usr/include/sched.h
/usr/include/linux/sched.h:#define CLONE_NEWTIME 0x00000080 /* New time
namespace */
This shows that the definition of CLONE_NEWTIME exists only in
/usr/include/linux/sched.h
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
At the end we should probably wonder if we want selftests to build with
old libc's that do not include latest defines. If we want to, then you
should probably replace sched.h by linux/sched.h . I'm not sure about
what to do really.
Since sched.h from libc may not define CLONE_NEWTIME on older systems,
should we explicitly include linux/sched.h to ensure compatibility with
older libc versions?
Thank you for your time and feedback!
Best regards,
Purva Yeshi
