diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index d11dbfbfcf..ba028ed230 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2019-10-16  Christian Biesinger  <cbiesinger@google.com>
+
+	* gdbsupport/gdb_setjmp.h (SIGSETJMP): Allow passing in the value to
+	pass on to sigsetjmp's second argument.
+	* cp-support.c (gdb_demangle): Unblock SIGSEGV if we caught a crash.
+
 2019-10-16  Keith Seitz  <keiths@redhat.com>
 
 	PR gdb/23567
diff --git a/gdb/cp-support.c b/gdb/cp-support.c
index cd732b60e7..253369b1ef 100644
--- a/gdb/cp-support.c
+++ b/gdb/cp-support.c
@@ -1539,7 +1539,16 @@ gdb_demangle (const char *name, int options)
       ofunc = signal (SIGSEGV, gdb_demangle_signal_handler);
 #endif
 
-      crash_signal = SIGSETJMP (gdb_demangle_jmp_buf);
+      /* The signal handler may keep the signal blocked when we longjmp out
+         of it.  If we have sigprocmask, we can use it to unblock the signal
+	 afterwards and we can avoid the performance overhead of saving the
+	 signal mask just in case the signal gets triggered.  Otherwise, just
+	 tell sigsetjmp to save the mask.  */
+#ifdef HAVE_SIGPROCMASK
+      crash_signal = SIGSETJMP (gdb_demangle_jmp_buf, 0);
+#else
+      crash_signal = SIGSETJMP (gdb_demangle_jmp_buf, 1);
+#endif
     }
 #endif
 
@@ -1559,6 +1568,14 @@ gdb_demangle (const char *name, int options)
 	{
 	  static int error_reported = 0;
 
+#ifdef HAVE_SIGPROCMASK
+	  /* If we got the signal, SIGSEGV may still be blocked; restore it.  */
+	  sigset_t segv_sig_set;
+	  sigemptyset (&segv_sig_set);
+	  sigaddset (&segv_sig_set, SIGSEGV);
+	  sigprocmask (SIG_UNBLOCK, &segv_sig_set, NULL);
+#endif
+
 	  if (!error_reported)
 	    {
 	      std::string short_msg
diff --git a/gdb/gdbsupport/gdb_setjmp.h b/gdb/gdbsupport/gdb_setjmp.h
index d4ebbfa8f2..499597085b 100644
--- a/gdb/gdbsupport/gdb_setjmp.h
+++ b/gdb/gdbsupport/gdb_setjmp.h
@@ -23,11 +23,13 @@
 
 #ifdef HAVE_SIGSETJMP
 #define SIGJMP_BUF		sigjmp_buf
-#define SIGSETJMP(buf)		sigsetjmp((buf), 1)
+#define SIGSETJMP(buf,val)	sigsetjmp((buf), val)
 #define SIGLONGJMP(buf,val)	siglongjmp((buf), (val))
 #else
 #define SIGJMP_BUF		jmp_buf
-#define SIGSETJMP(buf)		setjmp(buf)
+/* We ignore val here because that's safer and avoids having to check
+   whether _setjmp exists.  */
+#define SIGSETJMP(buf,val)	setjmp(buf)
 #define SIGLONGJMP(buf,val)	longjmp((buf), (val))
 #endif