seccomp: set seccompNotifyIsSupported

Otherwise seccomp_user_notify is never used.

PiperOrigin-RevId: 775381191

Author: avagin

pkg/sentry/platform/systrap/subprocess.go

@@ -187,6 +187,7 @@ func initSeccompNotify() {
 	switch errno {
 	case unix.EFAULT:
 		// seccomp unotify is supported.
+		seccompNotifyIsSupported = true
 	case unix.EINVAL:
 		log.Warningf("Seccomp user-space notification mechanism isn't " +
 			"supported by the kernel (available since Linux 5.0).")

pkg/sentry/platform/systrap/syscall_thread.go

@@ -224,7 +224,6 @@ func (t *syscallThread) syscall(sysno uintptr, args ...arch.SyscallArgument) (ui
 			return 0, errDeadSubprocess
 		}
 	} else {
-
 		// Notify the syscall thread about a new syscall request.
 		atomic.AddUint32(&sentryMsg.state, 1)
 		futexWakeUint32(&sentryMsg.state)