Index: gdb-7.7/gdb/linux-nat.c =================================================================== --- gdb-7.7.orig/gdb/linux-nat.c 2014-02-09 19:18:24.048554459 +0100 +++ gdb-7.7/gdb/linux-nat.c 2014-02-09 19:19:22.210622806 +0100 @@ -1529,8 +1529,22 @@ get_pending_status (struct lwp_info *lp, gdb_signal_to_string (signo)); } - if (*status == 0 && ptid_get_pid (lp->ptid) == pid_was_stopped) - *status = W_STOPCODE (SIGSTOP); + /* Workaround RHEL-5 kernel which has unreliable PTRACE_DETACH, SIGSTOP (that + many TIDs are left unstopped). See RH Bug 496732. */ + if (ptid_get_pid (lp->ptid) == pid_was_stopped) + { + int err; + + errno = 0; + err = kill_lwp (ptid_get_lwp (lp->ptid), SIGSTOP); + if (debug_linux_nat) + { + fprintf_unfiltered (gdb_stdlog, + "SC: lwp kill %d %s\n", + err, + errno ? safe_strerror (errno) : "ERRNO-OK"); + } + } return 0; }