misc: tst-poll: Proper synchronize with child before sending the signal
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Commit Message
When running the testsuite in parallel, for instance running make -j
$(nproc) check, occasionally tst-epoll fails with a timeout. It happens
because it sometimes takes a bit more than 10ms for the process to get
cloned and blocked by the syscall. In that case the signal is
sent to early, and the test fails with a timeout.
Checked on x86_64-linux-gnu.
---
sysdeps/unix/sysv/linux/tst-epoll.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
Comments
* Adhemerval Zanella:
> When running the testsuite in parallel, for instance running make -j
> $(nproc) check, occasionally tst-epoll fails with a timeout. It happens
> because it sometimes takes a bit more than 10ms for the process to get
> cloned and blocked by the syscall. In that case the signal is
> sent to early, and the test fails with a timeout.
>
> Checked on x86_64-linux-gnu.
> ---
> sysdeps/unix/sysv/linux/tst-epoll.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/sysdeps/unix/sysv/linux/tst-epoll.c b/sysdeps/unix/sysv/linux/tst-epoll.c
> index 3b38beae6e..545f506faa 100644
> --- a/sysdeps/unix/sysv/linux/tst-epoll.c
> +++ b/sysdeps/unix/sysv/linux/tst-epoll.c
> @@ -22,7 +22,7 @@
> #include <support/support.h>
> #include <support/xsignal.h>
> #include <support/xunistd.h>
> -#include <support/xtime.h>
> +#include <support/process_state.h>
> #include <stdlib.h>
> #include <sys/epoll.h>
>
> @@ -97,8 +97,8 @@ test_epoll_basic (epoll_wait_check_t epoll_wait_check)
> xclose (fds[0][0]);
> xclose (fds[1][1]);
>
> - /* Wait some time so child is blocked on the syscall. */
> - nanosleep (&(struct timespec) {0, 10000000}, NULL);
> + /* Wait until child is blocked on epoll_wait. */
> + support_process_state_wait (p, support_process_state_sleeping);
> TEST_COMPARE (kill (p, SIGUSR1), 0);
>
> int e = epoll_wait_check (efd, &event, 1, 500000000, &ss);
Looks okay. I don't see any blocking system calls between the fork and
the epoll_wait call.
Thanks,
Florian
On 2024-01-26 08:23, Adhemerval Zanella wrote:
> When running the testsuite in parallel, for instance running make -j
> $(nproc) check, occasionally tst-epoll fails with a timeout. It happens
> because it sometimes takes a bit more than 10ms for the process to get
> cloned and blocked by the syscall. In that case the signal is
> sent to early, and the test fails with a timeout.
>
> Checked on x86_64-linux-gnu.
> ---
> sysdeps/unix/sysv/linux/tst-epoll.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/sysdeps/unix/sysv/linux/tst-epoll.c b/sysdeps/unix/sysv/linux/tst-epoll.c
> index 3b38beae6e..545f506faa 100644
> --- a/sysdeps/unix/sysv/linux/tst-epoll.c
> +++ b/sysdeps/unix/sysv/linux/tst-epoll.c
> @@ -22,7 +22,7 @@
> #include <support/support.h>
> #include <support/xsignal.h>
> #include <support/xunistd.h>
> -#include <support/xtime.h>
> +#include <support/process_state.h>
> #include <stdlib.h>
> #include <sys/epoll.h>
>
> @@ -97,8 +97,8 @@ test_epoll_basic (epoll_wait_check_t epoll_wait_check)
> xclose (fds[0][0]);
> xclose (fds[1][1]);
>
> - /* Wait some time so child is blocked on the syscall. */
> - nanosleep (&(struct timespec) {0, 10000000}, NULL);
> + /* Wait until child is blocked on epoll_wait. */
> + support_process_state_wait (p, support_process_state_sleeping);
> TEST_COMPARE (kill (p, SIGUSR1), 0);
>
> int e = epoll_wait_check (efd, &event, 1, 500000000, &ss);
Thanks for working on the patch and sorry for taking so long to test
it. There is a minor typo on the subject (poll -> epoll), but otherwise
works as expected, so:
Tested-by: Aurelien Jarno <aurelien@aurel32.net>
@@ -22,7 +22,7 @@
#include <support/support.h>
#include <support/xsignal.h>
#include <support/xunistd.h>
-#include <support/xtime.h>
+#include <support/process_state.h>
#include <stdlib.h>
#include <sys/epoll.h>
@@ -97,8 +97,8 @@ test_epoll_basic (epoll_wait_check_t epoll_wait_check)
xclose (fds[0][0]);
xclose (fds[1][1]);
- /* Wait some time so child is blocked on the syscall. */
- nanosleep (&(struct timespec) {0, 10000000}, NULL);
+ /* Wait until child is blocked on epoll_wait. */
+ support_process_state_wait (p, support_process_state_sleeping);
TEST_COMPARE (kill (p, SIGUSR1), 0);
int e = epoll_wait_check (efd, &event, 1, 500000000, &ss);