Merge branch 'egil/erts/fix_scheduler_suspend/ERL-94/PR-978/OTP-13425' into maint-18

* egil/erts/fix_scheduler_suspend/ERL-94/PR-978/OTP-13425:
  erts: Fix install of suspend handler

4 files changed, 20 insertions, 10 deletions

diff --git a/erts/emulator/beam/break.c b/erts/emulator/beam/break.c
index 0ddf7f4e6d..298b30fff3 100644
--- a/erts/emulator/beam/break.c
+++ b/erts/emulator/beam/break.c
@@ -684,7 +684,7 @@ erl_crash_dump_v(char *file, int line, char* fmt, va_list args)
        crash dump. */
     erts_thr_progress_fatal_error_block(&tpd_buf);
 
-#ifdef ERTS_THR_HAVE_SIG_FUNCS
+#ifdef ERTS_SYS_SUSPEND_SIGNAL
     /*
      * We suspend all scheduler threads so that we can dump some
      * data about the currently running processes and scheduler data.
@@ -818,7 +818,7 @@ erl_crash_dump_v(char *file, int line, char* fmt, va_list args)
 
 #ifdef ERTS_SMP
 
-#if defined(ERTS_THR_HAVE_SIG_FUNCS)
+#ifdef ERTS_SYS_SUSPEND_SIGNAL
 
     /* We resume all schedulers so that we are in a known safe state
        when we write the rest of the crash dump */
diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index b4d5bf8fb6..8b85613e18 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -2134,6 +2134,7 @@ erl_start(int argc, char **argv)
 	init_break_handler();
     if (replace_intr)
 	erts_replace_intr();
+    sys_init_suspend_handler();
 #endif
 
     boot_argc = argc - i;  /* Number of arguments to init */
diff --git a/erts/emulator/sys/unix/erl_unix_sys.h b/erts/emulator/sys/unix/erl_unix_sys.h
index 8d4e98bf3a..b55180c509 100644
--- a/erts/emulator/sys/unix/erl_unix_sys.h
+++ b/erts/emulator/sys/unix/erl_unix_sys.h
@@ -311,6 +311,7 @@ extern SIGFUNC sys_signal(int, SIGFUNC);
 extern void sys_sigrelease(int);
 extern void sys_sigblock(int);
 extern void sys_stop_cat(void);
+extern void sys_init_suspend_handler(void);
 
 /*
  * Handling of floating point exceptions.
diff --git a/erts/emulator/sys/unix/sys.c b/erts/emulator/sys/unix/sys.c
index d94b37430e..cbd47db37f 100644
--- a/erts/emulator/sys/unix/sys.c
+++ b/erts/emulator/sys/unix/sys.c
@@ -226,8 +226,10 @@ static erts_smp_atomic_t sys_misc_mem_sz;
 static void smp_sig_notify(char c);
 static int sig_notify_fds[2] = {-1, -1};
 
+#if !defined(ETHR_UNUSABLE_SIGUSRX) && defined(ERTS_THR_HAVE_SIG_FUNCS)
 static int sig_suspend_fds[2] = {-1, -1};
 #define ERTS_SYS_SUSPEND_SIGNAL SIGUSR2
+#endif
 
 #endif
 
@@ -872,7 +874,7 @@ sigusr1_exit(void)
 
 #else
 
-#ifdef ERTS_SMP
+#ifdef ERTS_SYS_SUSPEND_SIGNAL
 void
 sys_thr_suspend(erts_tid_t tid) {
     erts_thr_kill(tid, ERTS_SYS_SUSPEND_SIGNAL);
@@ -900,7 +902,7 @@ static RETSIGTYPE user_signal1(int signum)
 #endif
 }
 
-#ifdef ERTS_SMP
+#ifdef ERTS_SYS_SUSPEND_SIGNAL
 #if (defined(SIG_SIGSET) || defined(SIG_SIGNAL))
 static RETSIGTYPE suspend_signal(void)
 #else
@@ -913,7 +915,7 @@ static RETSIGTYPE suspend_signal(int signum)
      res = read(sig_suspend_fds[0], buf, sizeof(int));
    } while (res < 0 && errno == EINTR);
 }
-#endif /* #ifdef ERTS_SMP */
+#endif /* #ifdef ERTS_SYS_SUSPEND_SIGNAL */
 
 #endif /* #ifndef ETHR_UNUSABLE_SIGUSRX */
 
@@ -966,13 +968,17 @@ void init_break_handler(void)
    sys_signal(SIGINT, request_break);
 #ifndef ETHR_UNUSABLE_SIGUSRX
    sys_signal(SIGUSR1, user_signal1);
-#ifdef ERTS_SMP
-   sys_signal(ERTS_SYS_SUSPEND_SIGNAL, suspend_signal);
-#endif /* #ifdef ERTS_SMP */
 #endif /* #ifndef ETHR_UNUSABLE_SIGUSRX */
    sys_signal(SIGQUIT, do_quit);
 }
 
+void sys_init_suspend_handler(void)
+{
+#ifdef ERTS_SYS_SUSPEND_SIGNAL
+   sys_signal(ERTS_SYS_SUSPEND_SIGNAL, suspend_signal);
+#endif
+}
+
 int sys_max_files(void)
 {
    return(max_files);
@@ -990,7 +996,7 @@ static void block_signals(void)
 #endif /* #ifndef ETHR_UNUSABLE_SIGUSRX */
 #endif /* #ifndef ERTS_SMP */
 
-#if defined(ERTS_SMP) && !defined(ETHR_UNUSABLE_SIGUSRX)
+#ifdef ERTS_SYS_SUSPEND_SIGNAL
    sys_sigblock(ERTS_SYS_SUSPEND_SIGNAL);
 #endif
 
@@ -1009,7 +1015,7 @@ static void unblock_signals(void)
 #endif /* #ifndef ETHR_UNUSABLE_SIGUSRX */
 #endif /* #ifndef ERTS_SMP */
 
-#if defined(ERTS_SMP) && !defined(ETHR_UNUSABLE_SIGUSRX)
+#ifdef ERTS_SYS_SUSPEND_SIGNAL
    sys_sigrelease(ERTS_SYS_SUSPEND_SIGNAL);
 #endif
 
@@ -3248,12 +3254,14 @@ init_smp_sig_notify(void)
 
 static void
 init_smp_sig_suspend(void) {
+#ifdef ERTS_SYS_SUSPEND_SIGNAL
   if (pipe(sig_suspend_fds) < 0) {
     erts_exit(ERTS_ABORT_EXIT,
 	     "Failed to create sig_suspend pipe: %s (%d)\n",
 	     erl_errno_id(errno),
 	     errno);
   }
+#endif
 }
 
 #ifdef __DARWIN__