With glibc >= 2.24, raise() temporarily blocks signals to make this function async-signal-safe. This has the consequence that the SIGCONT signal send by the call to PTRACE_CONT is delivered slightly later. In turn it means the next ptrace event received is the SIGCONT signal instead of the expected one. Unfortunately the libnih testsuite has very precise expectations, and do not expect such an event. Fix that by catching it and waiting for the following event. --- libnih-1.0.3.orig/nih/tests/test_child.c +++ libnih-1.0.3/nih/tests/test_child.c @@ -360,6 +360,14 @@ test_poll (void) waitid (P_PID, pid, &siginfo, WSTOPPED | WNOWAIT); + /* ptrace might catch the SIGCONT emitted with PTRACE_CONT, catch it + and wait for the next event. + */ + if (siginfo.si_code == CLD_TRAPPED && siginfo.si_status == SIGCONT) { + assert0 (ptrace (PTRACE_CONT, pid, NULL, NULL)); + waitid (P_PID, pid, &siginfo, WSTOPPED | WNOWAIT); + } + watch = nih_child_add_watch (NULL, pid, NIH_CHILD_TRAPPED, my_handler, &watch); @@ -420,6 +428,14 @@ test_poll (void) /* Wait for ptrace to stop the parent (signalling the fork) */ waitid (P_PID, pid, &siginfo, WSTOPPED | WNOWAIT); + /* ptrace might catch the SIGCONT emitted with PTRACE_CONT, catch it + and wait for the next event. + */ + if (siginfo.si_code == CLD_TRAPPED && siginfo.si_status == SIGCONT) { + assert0 (ptrace (PTRACE_CONT, pid, NULL, NULL)); + waitid (P_PID, pid, &siginfo, WSTOPPED | WNOWAIT); + } + /* Will be able to get the child pid now, we have to do it here * because we want to wait on it to ensure the test is synchronous; * otherwise nih_child_poll() could actually eat the child event @@ -489,6 +505,14 @@ test_poll (void) waitid (P_PID, pid, &siginfo, WSTOPPED | WNOWAIT); + /* ptrace might catch the SIGCONT emitted with PTRACE_CONT, catch it + and wait for the next event. + */ + if (siginfo.si_code == CLD_TRAPPED && siginfo.si_status == SIGCONT) { + assert0 (ptrace (PTRACE_CONT, pid, NULL, NULL)); + waitid (P_PID, pid, &siginfo, WSTOPPED | WNOWAIT); + } + watch = nih_child_add_watch (NULL, pid, NIH_CHILD_PTRACE, my_handler, &watch);