Bug 36016 – crash when NS fails

• Component: JavaScriptCore
• Status: UNCONFIRMED

My DNS server here was down so NS queries were going unanswered.  This resulted in libproxy->webkit crashes.  Indeed, having no NS services is not good, but it should not cause segfaults in applications.  That's a bug.

Here's the stacktrace:

Thread 12 (Thread 29625):
#0  0x0093c422 in __kernel_vsyscall ()
No symbol table info available.
#1  0x00884829 in __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/lowlevellock.S:142
No locals.
#2  0x0087ff3b in _L_lock_752 () from /lib/tls/i686/cmov/libpthread.so.0
No locals.
#3  0x0087fd51 in __pthread_mutex_lock (mutex=0x5b3b1d8) at pthread_mutex_lock.c:61
        ignore3 = 0
        ignore1 = -512
        ignore2 = 128
        __PRETTY_FUNCTION__ = "__pthread_mutex_lock"
        type = <value optimized out>
#4  0x05b37c39 in get_proxy_uri_sync (proxy_uri_resolver=0xa368490, uri=0xa670c60, cancellable=0xa658dc0, proxy_uri=0xa670c48) at soup-proxy-resolver-gnome.c:467
        status = <value optimized out>
#5  0x05b37f19 in libproxy_threadpool_func (user_data=0xa670c40, thread_data=0x0) at soup-proxy-resolver-gnome.c:410
No locals.
#6  0x0044b9af in g_thread_pool_thread_proxy (data=0xa65bd30) at /build/buildd/glib2.0-2.22.3/glib/gthreadpool.c:265
        task = 0xa670c40
        pool = 0xa65bd30
#7  0x0044a37f in g_thread_create_proxy (data=0xa66b6e0) at /build/buildd/glib2.0-2.22.3/glib/gthread.c:635
        __PRETTY_FUNCTION__ = "g_thread_create_proxy"
#8  0x0087d80e in start_thread (arg=0xb075cb70) at pthread_create.c:300
        __res = <value optimized out>
        __ignore1 = <value optimized out>
        __ignore2 = <value optimized out>
        pd = 0xb075cb70
        now = <value optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {8970228, 0, 4001536, -1334459384, 1260261021, -1355287556}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = <value optimized out>
        robust = <value optimized out>
#9  0x089068de in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130
No locals.

Thread 11 (Thread 29624):
#0  0x0093c422 in __kernel_vsyscall ()
No symbol table info available.
#1  0x00884829 in __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/lowlevellock.S:142
No locals.
#2  0x0087ff3b in _L_lock_752 () from /lib/tls/i686/cmov/libpthread.so.0
No locals.
#3  0x0087fd51 in __pthread_mutex_lock (mutex=0x5b3b1d8) at pthread_mutex_lock.c:61
        ignore3 = 0
        ignore1 = -512
        ignore2 = 128
        __PRETTY_FUNCTION__ = "__pthread_mutex_lock"
        type = <value optimized out>
#4  0x05b37c39 in get_proxy_uri_sync (proxy_uri_resolver=0xa3d6d00, uri=0xa670c20, cancellable=0xa658b20, proxy_uri=0xa670ce8) at soup-proxy-resolver-gnome.c:467
        status = <value optimized out>
#5  0x05b37f19 in libproxy_threadpool_func (user_data=0xa670ce0, thread_data=0x0) at soup-proxy-resolver-gnome.c:410
No locals.
#6  0x0044b9af in g_thread_pool_thread_proxy (data=0xa65bd30) at /build/buildd/glib2.0-2.22.3/glib/gthreadpool.c:265
        task = 0xa670ce0
        pool = 0xa65bd30
#7  0x0044a37f in g_thread_create_proxy (data=0xa6709d0) at /build/buildd/glib2.0-2.22.3/glib/gthread.c:635
        __PRETTY_FUNCTION__ = "g_thread_create_proxy"
#8  0x0087d80e in start_thread (arg=0xb0f5db70) at pthread_create.c:300
        __res = <value optimized out>
        __ignore1 = <value optimized out>
        __ignore2 = <value optimized out>
        pd = 0xb0f5db70
        now = <value optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {8970228, 0, 4001536, -1326066680, 1262358172, -1355287556}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = <value optimized out>
        robust = <value optimized out>
#9  0x089068de in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130
No locals.

Thread 10 (Thread 29623):
#0  0x0093c422 in __kernel_vsyscall ()
No symbol table info available.
#1  0x00884829 in __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/lowlevellock.S:142
No locals.
#2  0x0087ff3b in _L_lock_752 () from /lib/tls/i686/cmov/libpthread.so.0
No locals.
#3  0x0087fd51 in __pthread_mutex_lock (mutex=0x5b3b1d8) at pthread_mutex_lock.c:61
        ignore3 = 0
        ignore1 = -512
        ignore2 = 128
        __PRETTY_FUNCTION__ = "__pthread_mutex_lock"
        type = <value optimized out>
#4  0x05b37c39 in get_proxy_uri_sync (proxy_uri_resolver=0xa34dc10, uri=0xa670cc0, cancellable=0xa655c60, proxy_uri=0xa670ca8) at soup-proxy-resolver-gnome.c:467
        status = <value optimized out>
#5  0x05b37f19 in libproxy_threadpool_func (user_data=0xa670ca0, thread_data=0x0) at soup-proxy-resolver-gnome.c:410
No locals.
#6  0x0044b9af in g_thread_pool_thread_proxy (data=0xa65bd30) at /build/buildd/glib2.0-2.22.3/glib/gthreadpool.c:265
        task = 0xa670ca0
        pool = 0xa65bd30
#7  0x0044a37f in g_thread_create_proxy (data=0xa66bd50) at /build/buildd/glib2.0-2.22.3/glib/gthread.c:635
        __PRETTY_FUNCTION__ = "g_thread_create_proxy"
#8  0x0087d80e in start_thread (arg=0xb175eb70) at pthread_create.c:300
        __res = <value optimized out>
        __ignore1 = <value optimized out>
        __ignore2 = <value optimized out>
        pd = 0xb175eb70
        now = <value optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {8970228, 0, 4001536, -1317673976, 1264455327, -1355287556}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = <value optimized out>
        robust = <value optimized out>
#9  0x089068de in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130
No locals.

Thread 9 (Thread 29622):
#0  0x0093c422 in __kernel_vsyscall ()
No symbol table info available.
#1  0x00884829 in __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/lowlevellock.S:142
No locals.
#2  0x0087ff3b in _L_lock_752 () from /lib/tls/i686/cmov/libpthread.so.0
No locals.
#3  0x0087fd51 in __pthread_mutex_lock (mutex=0x5b3b1d8) at pthread_mutex_lock.c:61
        ignore3 = 0
        ignore1 = -512
        ignore2 = 128
        __PRETTY_FUNCTION__ = "__pthread_mutex_lock"
        type = <value optimized out>
#4  0x05b37c39 in get_proxy_uri_sync (proxy_uri_resolver=0xa2ee340, uri=0xa670d40, cancellable=0xa655ca0, proxy_uri=0xa670d28) at soup-proxy-resolver-gnome.c:467
        status = <value optimized out>
#5  0x05b37f19 in libproxy_threadpool_func (user_data=0xa670d20, thread_data=0x0) at soup-proxy-resolver-gnome.c:410
No locals.
#6  0x0044b9af in g_thread_pool_thread_proxy (data=0xa65bd30) at /build/buildd/glib2.0-2.22.3/glib/gthreadpool.c:265
        task = 0xa670d20
        pool = 0xa65bd30
#7  0x0044a37f in g_thread_create_proxy (data=0xa432750) at /build/buildd/glib2.0-2.22.3/glib/gthread.c:635
        __PRETTY_FUNCTION__ = "g_thread_create_proxy"
#8  0x0087d80e in start_thread (arg=0xb1f5fb70) at pthread_create.c:300
        __res = <value optimized out>
        __ignore1 = <value optimized out>
        __ignore2 = <value optimized out>
        pd = 0xb1f5fb70
        now = <value optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {8970228, 0, 4001536, -1309281272, 1266552478, -1355287556}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = <value optimized out>
        robust = <value optimized out>
#9  0x089068de in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130
No locals.

Thread 8 (Thread 29621):
#0  0x0093c422 in __kernel_vsyscall ()
No symbol table info available.
#1  0x00884829 in __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/lowlevellock.S:142
No locals.
#2  0x0087ff3b in _L_lock_752 () from /lib/tls/i686/cmov/libpthread.so.0
No locals.
#3  0x0087fd51 in __pthread_mutex_lock (mutex=0x5b3b1d8) at pthread_mutex_lock.c:61
        ignore3 = 0
        ignore1 = -512
        ignore2 = 128
        __PRETTY_FUNCTION__ = "__pthread_mutex_lock"
        type = <value optimized out>
#4  0x05b37c39 in get_proxy_uri_sync (proxy_uri_resolver=0xa19f080, uri=0xa670d00, cancellable=0xa655a00, proxy_uri=0xa670da8) at soup-proxy-resolver-gnome.c:467
        status = <value optimized out>
#5  0x05b37f19 in libproxy_threadpool_func (user_data=0xa670da0, thread_data=0x0) at soup-proxy-resolver-gnome.c:410
No locals.
#6  0x0044b9af in g_thread_pool_thread_proxy (data=0xa65bd30) at /build/buildd/glib2.0-2.22.3/glib/gthreadpool.c:265
        task = 0xa670da0
        pool = 0xa65bd30
#7  0x0044a37f in g_thread_create_proxy (data=0xa6775d8) at /build/buildd/glib2.0-2.22.3/glib/gthread.c:635
        __PRETTY_FUNCTION__ = "g_thread_create_proxy"
#8  0x0087d80e in start_thread (arg=0xb2760b70) at pthread_create.c:300
        __res = <value optimized out>
        __ignore1 = <value optimized out>
        __ignore2 = <value optimized out>
        pd = 0xb2760b70
        now = <value optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {8970228, 0, 4001536, -1300888568, 1285426841, -1355287556}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = <value optimized out>
        robust = <value optimized out>
#9  0x089068de in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130
No locals.

Thread 7 (Thread 29620):
#0  0x0093c422 in __kernel_vsyscall ()
No symbol table info available.
#1  0x00884829 in __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/lowlevellock.S:142
No locals.
#2  0x0087ff3b in _L_lock_752 () from /lib/tls/i686/cmov/libpthread.so.0
No locals.
#3  0x0087fd51 in __pthread_mutex_lock (mutex=0x5b3b1d8) at pthread_mutex_lock.c:61
        ignore3 = 0
        ignore1 = -512
        ignore2 = 128
        __PRETTY_FUNCTION__ = "__pthread_mutex_lock"
        type = <value optimized out>
#4  0x05b37c39 in get_proxy_uri_sync (proxy_uri_resolver=0xa3b9c20, uri=0xa670d80, cancellable=0xa22d620, proxy_uri=0xa670d68) at soup-proxy-resolver-gnome.c:467
        status = <value optimized out>
#5  0x05b37f19 in libproxy_threadpool_func (user_data=0xa670d60, thread_data=0x0) at soup-proxy-resolver-gnome.c:410
No locals.
#6  0x0044b9af in g_thread_pool_thread_proxy (data=0xa65bd30) at /build/buildd/glib2.0-2.22.3/glib/gthreadpool.c:265
        task = 0xa670d60
        pool = 0xa65bd30
#7  0x0044a37f in g_thread_create_proxy (data=0xa22a048) at /build/buildd/glib2.0-2.22.3/glib/gthread.c:635
        __PRETTY_FUNCTION__ = "g_thread_create_proxy"
#8  0x0087d80e in start_thread (arg=0xb2f61b70) at pthread_create.c:300
        __res = <value optimized out>
        __ignore1 = <value optimized out>
        __ignore2 = <value optimized out>
        pd = 0xb2f61b70
        now = <value optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {8970228, 0, 4001536, -1292495864, 1287523992, -1355287556}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = <value optimized out>
        robust = <value optimized out>
#9  0x089068de in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130
No locals.

Thread 6 (Thread 29619):
#0  0x0093c422 in __kernel_vsyscall ()
No symbol table info available.
#1  0x00884829 in __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/lowlevellock.S:142
No locals.
#2  0x0087ff3b in _L_lock_752 () from /lib/tls/i686/cmov/libpthread.so.0
No locals.
#3  0x0087fd51 in __pthread_mutex_lock (mutex=0x5b3b1d8) at pthread_mutex_lock.c:61
        ignore3 = 0
        ignore1 = -512
        ignore2 = 128
        __PRETTY_FUNCTION__ = "__pthread_mutex_lock"
        type = <value optimized out>
#4  0x05b37c39 in get_proxy_uri_sync (proxy_uri_resolver=0xa2d5240, uri=0xa670ac0, cancellable=0xa65ae60, proxy_uri=0xa670c08) at soup-proxy-resolver-gnome.c:467
        status = <value optimized out>
#5  0x05b37f19 in libproxy_threadpool_func (user_data=0xa670c00, thread_data=0x0) at soup-proxy-resolver-gnome.c:410
No locals.
#6  0x0044b9af in g_thread_pool_thread_proxy (data=0xa65bd30) at /build/buildd/glib2.0-2.22.3/glib/gthreadpool.c:265
        task = 0xa670c00
        pool = 0xa65bd30
#7  0x0044a37f in g_thread_create_proxy (data=0xa66be00) at /build/buildd/glib2.0-2.22.3/glib/gthread.c:635
        __PRETTY_FUNCTION__ = "g_thread_create_proxy"
#8  0x0087d80e in start_thread (arg=0xb3762b70) at pthread_create.c:300
        __res = <value optimized out>
        __ignore1 = <value optimized out>
        __ignore2 = <value optimized out>
        pd = 0xb3762b70
        now = <value optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {8970228, 0, 4001536, -1284103160, 1289621147, -1355287556}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = <value optimized out>
        robust = <value optimized out>
#9  0x089068de in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130
No locals.

Thread 5 (Thread 29618):
#0  0x0093c422 in __kernel_vsyscall ()
No symbol table info available.
#1  0x00884829 in __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/lowlevellock.S:142
No locals.
#2  0x0087ff3b in _L_lock_752 () from /lib/tls/i686/cmov/libpthread.so.0
No locals.
#3  0x0087fd51 in __pthread_mutex_lock (mutex=0x5b3b1d8) at pthread_mutex_lock.c:61
        ignore3 = 0
        ignore1 = -512
        ignore2 = 128
        __PRETTY_FUNCTION__ = "__pthread_mutex_lock"
        type = <value optimized out>
#4  0x05b37c39 in get_proxy_uri_sync (proxy_uri_resolver=0xa32d590, uri=0xa670e00, cancellable=0xa22d0c0, proxy_uri=0xa670dc8) at soup-proxy-resolver-gnome.c:467
        status = <value optimized out>
#5  0x05b37f19 in libproxy_threadpool_func (user_data=0xa670dc0, thread_data=0x0) at soup-proxy-resolver-gnome.c:410
No locals.
#6  0x0044b9af in g_thread_pool_thread_proxy (data=0xa65bd30) at /build/buildd/glib2.0-2.22.3/glib/gthreadpool.c:265
        task = 0xa670dc0
        pool = 0xa65bd30
#7  0x0044a37f in g_thread_create_proxy (data=0xa6255d0) at /build/buildd/glib2.0-2.22.3/glib/gthread.c:635
        __PRETTY_FUNCTION__ = "g_thread_create_proxy"
#8  0x0087d80e in start_thread (arg=0xb3f63b70) at pthread_create.c:300
        __res = <value optimized out>
        __ignore1 = <value optimized out>
        __ignore2 = <value optimized out>
        pd = 0xb3f63b70
        now = <value optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {8970228, 0, 4001536, -1275710456, 1291718298, -1355287556}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = <value optimized out>
        robust = <value optimized out>
#9  0x089068de in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130
No locals.

Thread 4 (Thread 29585):
#0  0x0093c422 in __kernel_vsyscall ()
No symbol table info available.
#1  0x088f8c96 in *__GI___poll (fds=0x897aff4, nfds=22, timeout=46) at ../sysdeps/unix/sysv/linux/poll.c:87
        resultvar = <value optimized out>
        oldtype = 0
        result = <value optimized out>
#2  0x0043054b in IA__g_poll (fds=0xa3adcd0, nfds=22, timeout=46) at /build/buildd/glib2.0-2.22.3/glib/gpoll.c:127
No locals.
#3  0x0042356b in g_main_context_poll (context=0x9f8c390, block=<value optimized out>, dispatch=1, self=0x9f51220) at /build/buildd/glib2.0-2.22.3/glib/gmain.c:2904
        poll_func = 0x430520 <IA__g_poll>
#4  g_main_context_iterate (context=0x9f8c390, block=<value optimized out>, dispatch=1, self=0x9f51220) at /build/buildd/glib2.0-2.22.3/glib/gmain.c:2586
        max_priority = 2147483647
        timeout = 46
        some_ready = <value optimized out>
        nfds = 22
        allocated_nfds = <value optimized out>
        fds = <value optimized out>
        __PRETTY_FUNCTION__ = "g_main_context_iterate"
#5  0x00423b9f in IA__g_main_loop_run (loop=0xa198148) at /build/buildd/glib2.0-2.22.3/glib/gmain.c:2799
        self = 0x9f51220
        __PRETTY_FUNCTION__ = "IA__g_main_loop_run"
#6  0x00dec419 in IA__gtk_main () at /usr/src/gtk+2.0-2.18.3/gtk/gtkmain.c:1218
        tmp_list = 0x9fb6e18
        functions = 0x0
        init = 0x0
        loop = 0xa198148
#7  0x08063870 in main (argc=1, argv=0xbf910124) at main.c:154
        context = <value optimized out>
        program = <value optimized out>
        app = 0xbf910078
        new_app = 0x719d20
        gc = 0x9f92ec0
        l = 0x9fba72c

Thread 3 (Thread 29626):
#0  0x0093c422 in __kernel_vsyscall ()
No symbol table info available.
#1  0x00884829 in __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/lowlevellock.S:142
No locals.
#2  0x0087ff3b in _L_lock_752 () from /lib/tls/i686/cmov/libpthread.so.0
No locals.
#3  0x0087fd51 in __pthread_mutex_lock (mutex=0x5b3b1d8) at pthread_mutex_lock.c:61
        ignore3 = 0
        ignore1 = -512
        ignore2 = 128
        __PRETTY_FUNCTION__ = "__pthread_mutex_lock"
        type = <value optimized out>
#4  0x05b37c39 in get_proxy_uri_sync (proxy_uri_resolver=0xa198490, uri=0xa670bc0, cancellable=0xa658d80, proxy_uri=0xa670c88) at soup-proxy-resolver-gnome.c:467
        status = <value optimized out>
#5  0x05b37f19 in libproxy_threadpool_func (user_data=0xa670c80, thread_data=0x0) at soup-proxy-resolver-gnome.c:410
No locals.
#6  0x0044b9af in g_thread_pool_thread_proxy (data=0xa65bd30) at /build/buildd/glib2.0-2.22.3/glib/gthreadpool.c:265
        task = 0xa670c80
        pool = 0xa65bd30
#7  0x0044a37f in g_thread_create_proxy (data=0xa66b7c8) at /build/buildd/glib2.0-2.22.3/glib/gthread.c:635
        __PRETTY_FUNCTION__ = "g_thread_create_proxy"
#8  0x0087d80e in start_thread (arg=0xaff5bb70) at pthread_create.c:300
        __res = <value optimized out>
        __ignore1 = <value optimized out>
        __ignore2 = <value optimized out>
        pd = 0xaff5bb70
        now = <value optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {8970228, 0, 4001536, -1342852088, 1274941090, -1355287556}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = <value optimized out>
        robust = <value optimized out>
#9  0x089068de in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130
No locals.

Thread 2 (Thread 29637):
#0  0x0093c422 in __kernel_vsyscall ()
No symbol table info available.
#1  0x00881e15 in pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/pthread_cond_wait.S:122
No locals.
#2  0xb4e97447 in WTF::TCMalloc_PageHeap::scavengerThread (this=0xb590ec60) at ../JavaScriptCore/wtf/FastMalloc.cpp:2291
No locals.
#3  0xb4e97481 in WTF::TCMalloc_PageHeap::runScavengerThread (context=0xb590ec60) at ../JavaScriptCore/wtf/FastMalloc.cpp:1429
No locals.
#4  0x0087d80e in start_thread (arg=0xaecffb70) at pthread_create.c:300
        __res = <value optimized out>
        __ignore1 = <value optimized out>
        __ignore2 = <value optimized out>
        pd = 0xaecffb70
        now = <value optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {8970228, 0, 4001536, -1362103288, 1065225888, -1355287556}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = <value optimized out>
        robust = <value optimized out>
#5  0x089068de in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130
No locals.

Thread 1 (Thread 29627):
#0  0x072884af in ?? ()
No symbol table info available.
#1  0xb4e2cb88 in JSC::JITCode::execute (this=0x200, program=0xaf759fc0, callFrame=0xb594be24, scopeChain=0xb5937168, thisObj=0xaee80000, exception=0xaf759ff8) at ../JavaScriptCore/jit/JITCode.h:79
No locals.
#2  JSC::Interpreter::execute (this=0x200, program=0xaf759fc0, callFrame=0xb594be24, scopeChain=0xb5937168, thisObj=0xaee80000, exception=0xaf759ff8) at ../JavaScriptCore/interpreter/Interpreter.cpp:655
        oldEnd = 0xae0ff000
        lastGlobalObject = 0xaee80000
        globalObject = 0xaee80000
        newEnd = <value optimized out>
        newCallFrame = <value optimized out>
#3  0xb4ea911f in JSC::evaluate (exec=0xb594be24, scopeChain=..., source=..., thisValue=...) at ../JavaScriptCore/runtime/Completion.cpp:60
        thisObj = 0xaee80000
        exception = {u = {asEncodedJSValue = -8589934592, asDouble = -nan(0xffffe00000000), asBits = {payload = 0, tag = -2}}}
        program = {<JSC::ScriptExecutable> = {<JSC::ExecutableBase> = {<WTF::RefCounted<JSC::ExecutableBase>> = {<WTF::RefCountedBase> = {m_refCount = 1}, <WTFNoncopyable::Noncopyable> = {<WTF::FastAllocBase> = {<No data fields>}, <No data fields>}, <No data fields>}, _vptr.ExecutableBase = 0xb587f940, static NUM_PARAMETERS_IS_HOST = <optimized out>, static NUM_PARAMETERS_NOT_COMPILED = <optimized out>, m_numParameters = -1, m_jitCode = {m_ref = {m_code = {m_value = 0x72868e0}, m_executablePool = {<WTF::FastAllocBase> = {<No data fields>}, m_ptr = 0xb59434b0}, m_size = 235}}}, m_source = {m_provider = {<WTF::FastAllocBase> = {<No data fields>}, m_ptr = 0xb5937678}, m_startChar = 0, m_endChar = 94, m_firstLine = 1}, m_features = 0, m_firstLine = 1, m_lastLine = 1}, m_programCodeBlock = 0xb5966ee0}
        error = <value optimized out>
        result = <value optimized out>
#4  0xb4dd70bf in JSEvaluateScript (ctx=0xb594be24, script=0xb593e2f0, thisObject=0x0, sourceURL=0x0, startingLineNumber=1, exception=0x0) at ../JavaScriptCore/API/JSBase.cpp:54
        globalObject = 0xaee80000
        completion = {m_type = JSC::Normal, m_value = {u = {asEncodedJSValue = -8589934592, asDouble = -nan(0xffffe00000000), asBits = {payload = 0, tag = -2}}}}
        lock = {<WTFNoncopyable::Noncopyable> = {<WTF::FastAllocBase> = {<No data fields>}, <No data fields>}, m_lockBehavior = JSC::SilenceAssertionsOnly}
        source = {m_provider = {<WTF::FastAllocBase> = {<No data fields>}, m_ptr = 0xb5937678}, m_startChar = 0, m_endChar = 94, m_firstLine = 1}
#5  0x025693bb in webkit_pacrunner (self=0xa632100, pac=0xa66b920, url=0xa675b68) at webkit.c:186
        str = 0xb593e2f0
        val = <value optimized out>
        tmp = <value optimized out>
        ctxs = 0xa117808
#6  0x053bc812 in px_proxy_factory_get_proxies (self=0xa632100, url=0xa229c18 "http://weather.noaa.gov/cgi-bin/mgetmetar.pl?cccc=LFPB") at proxy_factory.c:732
        realurl = 0xa675b68
        config = <value optimized out>
        response = 0xa6763e8
        tmp = <value optimized out>
        order = <value optimized out>
        orderv = 0x53bd8b0
        wpad_fallback_env = <value optimized out>
        do_wpad_fallback = 174504216
        ignores = 0xa66b918
#7  0x05b37a91 in get_proxy_for_uri (uri=<value optimized out>, proxy_uri=<value optimized out>) at soup-proxy-resolver-gnome.c:338
        uristr = 0xa229c18 "http://weather.noaa.gov/cgi-bin/mgetmetar.pl?cccc=LFPB"
        proxies = 0x0
        got_proxy = <value optimized out>
#8  0x05b37cda in get_proxy_uri_sync (proxy_uri_resolver=0xa335c40, uri=0xa670e40, cancellable=0xa22d360, proxy_uri=0xa670e28) at soup-proxy-resolver-gnome.c:472
        status = <value optimized out>
#9  0x05b37f19 in libproxy_threadpool_func (user_data=0xa670e20, thread_data=0x0) at soup-proxy-resolver-gnome.c:410
No locals.
#10 0x0044b9af in g_thread_pool_thread_proxy (data=0xa65bd30) at /build/buildd/glib2.0-2.22.3/glib/gthreadpool.c:265
        task = 0xa670e20
        pool = 0xa65bd30
#11 0x0044a37f in g_thread_create_proxy (data=0xa66ef50) at /build/buildd/glib2.0-2.22.3/glib/gthread.c:635
        __PRETTY_FUNCTION__ = "g_thread_create_proxy"
#12 0x0087d80e in start_thread (arg=0xaf75ab70) at pthread_create.c:300
        __res = <value optimized out>
        __ignore1 = <value optimized out>
        __ignore2 = <value optimized out>
        pd = 0xaf75ab70
        now = <value optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {8970228, 0, 4001536, -1351244792, 1272843939, -1355287556}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = <value optimized out>
        robust = <value optimized out>
#13 0x089068de in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130

To reproduce I would think simply stopping a gnome machine, configured to use a proxy for Internet access from being able to resolve names and configuring at least one (i.e. weather) location in the clock should yield the panel segfaulting soon enough (i.e. when an update is attempted).  Probably killing the panel so that it tries to update on restart would speed up the segfault.

Assuming I could reproduce this, what could I do to help get to the bottom of this issue?

Any update on this?  I've provided instructions on how to reproduce as well as offered to follow some instruction and return some results to help get to the bottom of this.