I have found a core file from gnome-shell in my home directory,
where gnome-shell got aborted by librthread because gnome-shell
was trying to lock the malloc mutex recursively.
What's happening here is that gnome-shell wants to print a gjs stack
trace when certain signals are caught, and sets up a signal handler
which uses stdio and malloc. This isn't safe. A correct approach would
be to print a stack dump from within the application's main loop after
a signal was caught. However, this main loop lives in mutter code, not
iin gnome-shell code. So the correct fix is a lot more involved than
the diff below and would likely require API changes in mutter to allow
gnome-shell to hook its handler at a suitable place.
For now, just disable this signal handler, which will always crash
on OpenBSD rather than producing stack trace information, to prevent
gnome-shell from littering home directories with useless core dumps.
ok?
Index: Makefile
===================================================================
RCS file: /cvs/ports/x11/gnome/shell/Makefile,v
retrieving revision 1.168
diff -u -p -r1.168 Makefile
--- Makefile 6 Mar 2019 08:29:36 -0000 1.168
+++ Makefile 25 Mar 2019 07:28:18 -0000
@@ -6,7 +6,7 @@ COMMENT= next generation GNOME shell
GNOME_PROJECT= gnome-shell
GNOME_VERSION= 3.30.2
-REVISION= 0
+REVISION= 1
# GPLv2+
PERMIT_PACKAGE_CDROM= Yes
Index: patches/patch-src_main_c
===================================================================
RCS file: patches/patch-src_main_c
diff -N patches/patch-src_main_c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ patches/patch-src_main_c 25 Mar 2019 07:28:46 -0000
@@ -0,0 +1,47 @@
+$OpenBSD$
+Disable broken signal handler which locks the malloc mutex recursively.
+
+#0 thrkill () at -:3
+#1 0x00000dc8de8ca89e in _libc_abort () at /usr/src/lib/libc/stdlib/abort.c:51
+#2 0x00000dc8de93cbba in _rthread_mutex_timedlock (mutexp=Variable "mutexp"
is
+not available.
+)
+ at /usr/src/lib/libc/thread/rthread_mutex.c:117
+#3 0x00000dc8de8adf12 in malloc (size=128)
+ at /usr/src/lib/libc/stdlib/malloc.c:1253
+#4 0x00000dc8de947746 in _libc_vasprintf (str=0xdc9b1be0b08,
+ fmt=0xdc935649217 "== Stack trace for context %p ==\n", ap=0xdc9b1be0ce0)
+ at /usr/src/lib/libc/stdio/vasprintf.c:39
+#5 0x00000dc975b5cbbd in g_vasprintf (string=0xdc9b1be0b08,
+ format=0xdc935649217 "== Stack trace for context %p ==\n",
+ args=0xdc9b1be0ce0) at ../glib-2.58.3/glib/gprintf.c:330
+#6 0x00000dc975b13661 in g_strdup_vprintf (
+ format=0xdc935649217 "== Stack trace for context %p ==\n",
+ args=0xdc9b1be0ce0) at ../glib-2.58.3/glib/gstrfuncs.c:514
+#7 0x00000dc975aef17f in g_printerr (
+ format=0xdc935649217 "== Stack trace for context %p ==\n")
+ at ../glib-2.58.3/glib/gmessages.c:3247
+#8 0x00000dc935781742 in gjs_context_print_stack_stderr ()
+ from /usr/local/lib/libgjs.so.5.0
+#9 0x00000dc9357817c5 in gjs_dumpstack () from /usr/local/lib/libgjs.so.5.0
+#10 0x00000dc6bd8b62f0 in dump_gjs_stack_on_signal_handler (signo=6)
+
+Index: src/main.c
+--- src/main.c.orig
++++ src/main.c
+@@ -348,6 +348,7 @@ dump_gjs_stack_on_signal_handler (int signo)
+ static void
+ dump_gjs_stack_on_signal (int signo)
+ {
++#if 0 /* this handler is disabled because it triggers malloc mutex recursion
*/
+ struct sigaction sa = { 0 };
+
+ sa.sa_flags = SA_RESETHAND | SA_NODEFER;
+@@ -356,6 +357,7 @@ dump_gjs_stack_on_signal (int signo)
+
+ sigaction (signo, &sa, NULL);
+ _tracked_signals[signo] = TRUE;
++#endif
+ }
+
+ static gboolean
