Hang (possibly related to Automatic proxy configuration?)

Without warning (i.e. epiphany had been working perfectly well for browsing various pages), visiting a URL caused the entire browser to freeze. Here's what gdb said:

(gdb) thread apply all bt

Thread 7 (Thread -1247204432 (LWP 10595)):
#0 0xffffe410 in __kernel_vsyscall ()
#1 0xb7f168c4 in poll () from /lib/tls/i686/cmov/libc.so.6
#2 0xb7fa8086 in PR_Poll () from /usr/lib/libnspr4.so
#3 0xb67b8080 in NSGetModule () from /usr/lib/firefox/components/libnecko.so
#4 0xb67b87c5 in NSGetModule () from /usr/lib/firefox/components/libnecko.so
#5 0xb6f91b29 in nsIThread::IsMainThread () from /usr/lib/firefox/libxpcom_core.so
#6 0xb7fa979d in PR_Select () from /usr/lib/libnspr4.so
#7 0xb7096341 in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#8 0xb7f204ee in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 6 (Thread -1271174224 (LWP 10598)):
#0 0xffffe410 in __kernel_vsyscall ()
#1 0xb7098c76 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0
#2 0xb7f2d4e7 in pthread_cond_wait () from /lib/tls/i686/cmov/libc.so.6
#3 0xb7fa45f0 in PR_WaitCondVar () from /usr/lib/libnspr4.so
#4 0xb6f93eb4 in NS_NewThread () from /usr/lib/firefox/libxpcom_core.so
#5 0xb6f91b29 in nsIThread::IsMainThread () from /usr/lib/firefox/libxpcom_core.so
#6 0xb7fa979d in PR_Select () from /usr/lib/libnspr4.so
#7 0xb7096341 in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#8 0xb7f204ee in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 5 (Thread -1329828944 (LWP 10671)):
#0 0xffffe410 in __kernel_vsyscall ()
#1 0xb7f168c4 in poll () from /lib/tls/i686/cmov/libc.so.6
#2 0xb0bd402e in QueueRunnable::waitOnPipe () from /usr/lib/j2se/1.4/jre/plugin/i386/mozilla/libjavaplugin_oji.so
#3 0xb0bd410a in QueueRunnable::threadEntry () from /usr/lib/j2se/1.4/jre/plugin/i386/mozilla/libjavaplugin_oji.so
#4 0xb7fa979d in PR_Select () from /usr/lib/libnspr4.so
#5 0xb7096341 in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#6 0xb7f204ee in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 4 (Thread -1338221648 (LWP 10672)):
#0 0xffffe410 in __kernel_vsyscall ()
#1 0xb7f168c4 in poll () from /lib/tls/i686/cmov/libc.so.6
---Type <return> to continue, or q <return> to quit---
#2 0xb0bd402e in QueueRunnable::waitOnPipe () from /usr/lib/j2se/1.4/jre/plugin/i386/mozilla/libjavaplugin_oji.so
#3 0xb0bd410a in QueueRunnable::threadEntry () from /usr/lib/j2se/1.4/jre/plugin/i386/mozilla/libjavaplugin_oji.so
#4 0xb7fa979d in PR_Select () from /usr/lib/libnspr4.so
#5 0xb7096341 in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#6 0xb7f204ee in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 3 (Thread -1260696656 (LWP 1281)):
#0 0xffffe410 in __kernel_vsyscall ()
#1 0xb7f168c4 in poll () from /lib/tls/i686/cmov/libc.so.6
#2 0xb6ff57d8 in g_main_context_check () from /usr/lib/libglib-2.0.so.0
#3 0xb6ff5ca8 in g_main_loop_run () from /usr/lib/libglib-2.0.so.0
#4 0xb7a3970e in link_thread_io_context () from /usr/lib/libORBit-2.so.0
#5 0xb700e5d2 in g_static_private_free () from /usr/lib/libglib-2.0.so.0
#6 0xb7096341 in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#7 0xb7f204ee in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 2 (Thread -1297097808 (LWP 1451)):
#0 0xffffe410 in __kernel_vsyscall ()
#1 0xb7f168c4 in poll () from /lib/tls/i686/cmov/libc.so.6
#2 0xb7afb647 in __res_queriesmatch () from /lib/tls/i686/cmov/libresolv.so.2
#3 0xb7afa113 in __libc_res_nquery () from /lib/tls/i686/cmov/libresolv.so.2
#4 0xb7afa3d8 in __res_nquery () from /lib/tls/i686/cmov/libresolv.so.2
#5 0xb7afa93e in __libc_res_nsearch () from /lib/tls/i686/cmov/libresolv.so.2
#6 0xb52612be in _nss_dns_gethostbyname3_r () from /lib/tls/i686/cmov/libnss_dns.so.2
#7 0xb52615d7 in _nss_dns_gethostbyname2_r () from /lib/tls/i686/cmov/libnss_dns.so.2
#8 0xb7f08112 in sched_setaffinity () from /lib/tls/i686/cmov/libc.so.6
#9 0xb7f095a1 in getaddrinfo () from /lib/tls/i686/cmov/libc.so.6
#10 0xb7f9e140 in PR_GetAddrInfoByName () from /usr/lib/libnspr4.so
#11 0xb67c3795 in NSGetModule () from /usr/lib/firefox/components/libnecko.so
#12 0xb7fa979d in PR_Select () from /usr/lib/libnspr4.so
#13 0xb7096341 in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#14 0xb7f204ee in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 1 (Thread -1227376960 (LWP 10591)):
#0 0xffffe410 in __kernel_vsyscall ()
---Type <return> to continue, or q <return> to quit---
#1 0xb7098c76 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0
#2 0xb7f2d4e7 in pthread_cond_wait () from /lib/tls/i686/cmov/libc.so.6
#3 0xb7fa45f0 in PR_WaitCondVar () from /usr/lib/libnspr4.so
#4 0xb7fa48b4 in PR_Wait () from /usr/lib/libnspr4.so
#5 0xb67c2660 in NSGetModule () from /usr/lib/firefox/components/libnecko.so
#6 0xb6fa5d49 in XPTC_InvokeByIndex () from /usr/lib/firefox/libxpcom_core.so
#7 0xb6a0e8f3 in NSGetModule () from /usr/lib/firefox/components/libxpconnect.so
#8 0xb6a143e5 in NSGetModule () from /usr/lib/firefox/components/libxpconnect.so
#9 0xb698de8a in js_Invoke () from /usr/lib/firefox/libmozjs.so
#10 0xb6981bda in js_FreeStack () from /usr/lib/firefox/libmozjs.so
#11 0xb698e010 in js_Invoke () from /usr/lib/firefox/libmozjs.so
#12 0xb6a0c042 in NSGetModule () from /usr/lib/firefox/components/libxpconnect.so
#13 0xb6a075e6 in NSGetModule () from /usr/lib/firefox/components/libxpconnect.so
#14 0xb6fa681b in nsXPTCStubBase::Stub249 () from /usr/lib/firefox/libxpcom_core.so
#15 0x0ac0bbd0 in ?? ()
#16 0x00000004 in ?? ()
#17 0x0af9fbe0 in ?? ()
#18 0xbfcf2f94 in ?? ()
#19 0x0be8af88 in ?? ()
#20 0xb6fbdd4c in ?? () from /usr/lib/firefox/libxpcom_core.so
#21 0xbfcf2f94 in ?? ()
#22 0x0ac0bbd0 in ?? ()
#23 0x00000004 in ?? ()
#24 0xbfcf2f94 in ?? ()
#25 0x03cf2fb8 in ?? ()
#26 0xb6fac8af in nsCSubstring::Assign () from /usr/lib/firefox/libxpcom_core.so
#27 0xb67aa402 in NSGetModule () from /usr/lib/firefox/components/libnecko.so
#28 0xb67a8438 in NSGetModule () from /usr/lib/firefox/components/libnecko.so
#29 0xb67a3540 in NSGetModule () from /usr/lib/firefox/components/libnecko.so
#30 0xb60196ea in NSGetModule () from /usr/lib/firefox/components/libdocshell.so
#31 0xb6022f6f in NSGetModule () from /usr/lib/firefox/components/libdocshell.so
#32 0xb601b5a7 in NSGetModule () from /usr/lib/firefox/components/libdocshell.so
#33 0xb60182b6 in NSGetModule () from /usr/lib/firefox/components/libdocshell.so
#34 0xb5fce3d3 in NSGetModule () from /usr/lib/firefox/components/libwebbrwsr.so
#35 0xb7fd6a5f in gtk_moz_embed_get_title () from /usr/lib/firefox/libgtkembedmoz.so
---Type <return> to continue, or q <return> to quit---
#36 0xb7fd501b in gtk_moz_embed_load_url () from /usr/lib/firefox/libgtkembedmoz.so
#37 0x080b9c85 in _mozilla_embed_get_ephy_browser ()
#38 0x080e5023 in ephy_embed_load_url ()
#39 0x0807b7cf in ephy_shell_new_tab_full ()
#40 0x0807b8ab in ephy_shell_new_tab ()
#41 0x08086493 in ephy_window_get_notebook ()
#42 0x08103506 in ephy_marshal_OBJECT__STRING_OBJECT_FLAGS ()
#43 0xb705c1cd in g_cclosure_new_swap () from /usr/lib/libgobject-2.0.so.0
#44 0xb705c79f in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#45 0xb706b9ce in g_signal_stop_emission () from /usr/lib/libgobject-2.0.so.0
#46 0xb706c886 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#47 0xb706ce89 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#48 0x0809a218 in ephy_link_open ()
#49 0x08103506 in ephy_marshal_OBJECT__STRING_OBJECT_FLAGS ()
#50 0xb705c79f in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#51 0xb706b2ea in g_signal_stop_emission () from /usr/lib/libgobject-2.0.so.0
#52 0xb706c886 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#53 0xb706ce89 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#54 0x0809a218 in ephy_link_open ()
#55 0x0807e677 in ephy_tab_get_icon_address ()
#56 0x08102fde in ephy_marshal_BOOLEAN__OBJECT ()
#57 0xb705c79f in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#58 0xb706b2ea in g_signal_stop_emission () from /usr/lib/libgobject-2.0.so.0
#59 0xb706c886 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#60 0xb7070030 in g_signal_emit_by_name () from /usr/lib/libgobject-2.0.so.0
#61 0x080bad92 in _mozilla_embed_new_xul_dialog ()
#62 0xb762d6f3 in gtk_marshal_BOOLEAN__POINTER () from /usr/lib/libgtk-x11-2.0.so.0
#63 0xb705c79f in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#64 0xb706b2ea in g_signal_stop_emission () from /usr/lib/libgobject-2.0.so.0
#65 0xb706c886 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#66 0xb7676033 in gtk_signal_emit () from /usr/lib/libgtk-x11-2.0.so.0
#67 0xb7fda65c in gtk_moz_embed_get_title () from /usr/lib/firefox/libgtkembedmoz.so
#68 0xb62f502b in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#69 0xb63f1e98 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#70 0xb63e4ff5 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
---Type <return> to continue, or q <return> to quit---
#71 0xb62b5ad7 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#72 0xb62cc9e2 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#73 0xb62cc753 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#74 0xb62cc753 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#75 0xb62cc753 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#76 0xb62cc753 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#77 0xb62cc753 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#78 0xb62cc753 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#79 0xb62cc753 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#80 0xb62cc753 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#81 0xb62cc753 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#82 0xb62cc753 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#83 0xb6310ba6 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#84 0xb6319316 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#85 0xb613e1f5 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#86 0xb613e6bb in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#87 0xb62f7c78 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#88 0xb62fec65 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#89 0xb613e367 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#90 0xb61420d0 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#91 0xb63ccbd1 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#92 0xb63cdfbc in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#93 0xb63c4628 in NSGetModule () from /usr/lib/firefox/components/libgklayout.so
#94 0xb656cbfe in NSGetModule () from /usr/lib/firefox/components/libwidget_gtk2.so
#95 0xb6568d6c in ?? () from /usr/lib/firefox/components/libwidget_gtk2.so
#96 0x0b9bf9e8 in ?? ()
#97 0xbfcf64f0 in ?? ()
#98 0xbfcf6538 in ?? ()
#99 0xb6fe0147 in g_datalist_id_get_data () from /usr/lib/libglib-2.0.so.0
#100 0xb6568dcd in ?? () from /usr/lib/firefox/components/libwidget_gtk2.so
#101 0x0b9bf9e8 in ?? ()
#102 0x095d88e0 in ?? ()
#103 0x095c5df8 in ?? ()
#104 0xb705bb40 in g_closure_ref () from /usr/lib/libgobject-2.0.so.0
#105 0xb762e850 in _gtk_marshal_BOOLEAN__BOXED () from /usr/lib/libgtk-x11-2.0.so.0
---Type <return> to continue, or q <return> to quit---
#106 0xb705c79f in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#107 0xb706b2ea in g_signal_stop_emission () from /usr/lib/libgobject-2.0.so.0
#108 0xb706c886 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#109 0xb706ce89 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#110 0xb7710c4f in gtk_widget_activate () from /usr/lib/libgtk-x11-2.0.so.0
#111 0xb762cfcd in gtk_propagate_event () from /usr/lib/libgtk-x11-2.0.so.0
#112 0xb762d3db in gtk_main_do_event () from /usr/lib/libgtk-x11-2.0.so.0
#113 0xb74d0ddc in _gdk_events_queue () from /usr/lib/libgdk-x11-2.0.so.0
#114 0xb6ff28c6 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#115 0xb6ff5986 in g_main_context_check () from /usr/lib/libglib-2.0.so.0
#116 0xb6ff5ca8 in g_main_loop_run () from /usr/lib/libglib-2.0.so.0
#117 0xb762c6d5 in gtk_main () from /usr/lib/libgtk-x11-2.0.so.0
#118 0x08076491 in main ()
#0 0xffffe410 in __kernel_vsyscall ()
(gdb)

The only change I've recently made to my configuration is I'm temporarily on a different network that requires use of this proxy configuration: http://www.it.usyd.edu.au/proxy.pac, rather than the direct connection I usually have.