I'm on a fairly disk / resource constrained machine but installed apport-retrace and got the following stack trace (Lucid with an update just this evening) from _usr_lib_gvfs_gvfsd-smb.1000.crash:

--- stack trace ---
#0  0x00944422 in __kernel_vsyscall ()
No symbol table info available.
#1  0x00712641 in raise () from /lib/tls/i686/cmov/libc.so.6
No symbol table info available.
#2  0x00715a72 in abort () from /lib/tls/i686/cmov/libc.so.6
No symbol table info available.
#3  0x00680dd3 in g_assertion_message () from /lib/libglib-2.0.so.0
No symbol table info available.
#4  0x0068142d in g_assertion_message_expr () from /lib/libglib-2.0.so.0
No symbol table info available.
#5  0x00a08802 in ?? () from /usr/lib/libgnome-keyring.so.0
No symbol table info available.
#6  0x00a07b55 in ?? () from /usr/lib/libgnome-keyring.so.0
No symbol table info available.
#7  0x00a088fc in ?? () from /usr/lib/libgnome-keyring.so.0
No symbol table info available.
#8  0x00a095b1 in ?? () from /usr/lib/libgnome-keyring.so.0
No symbol table info available.
#9  0x00a11a16 in gnome_keyring_set_network_password_sync () from /usr/lib/libgnome-keyring.so.0
No symbol table info available.
#10 0x080647cd in ?? ()
No symbol table info available.
#11 0x08052696 in ?? ()
No symbol table info available.
#12 0x08059b68 in ?? ()
No symbol table info available.
#13 0x080589fd in ?? ()
No symbol table info available.
#14 0x0805476e in ?? ()
No symbol table info available.
#15 0x00685cec in ?? () from /lib/libglib-2.0.so.0
No symbol table info available.
#16 0x00683dcf in ?? () from /lib/libglib-2.0.so.0
No symbol table info available.
#17 0x0060a96e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
No symbol table info available.
#18 0x007b59de in clone () from /lib/tls/i686/cmov/libc.so.6
No symbol table info available.
--- source code stack trace ---
#0  0x00944422 in __kernel_vsyscall ()
#1  0x00712641 in raise () from /lib/tls/i686/cmov/libc.so.6
#2  0x00715a72 in abort () from /lib/tls/i686/cmov/libc.so.6
#3  0x00680dd3 in g_assertion_message () from /lib/libglib-2.0.so.0
#4  0x0068142d in g_assertion_message_expr () from /lib/libglib-2.0.so.0
#5  0x00a08802 in ?? () from /usr/lib/libgnome-keyring.so.0
#6  0x00a07b55 in ?? () from /usr/lib/libgnome-keyring.so.0
#7  0x00a088fc in ?? () from /usr/lib/libgnome-keyring.so.0
#8  0x00a095b1 in ?? () from /usr/lib/libgnome-keyring.so.0
#9  0x00a11a16 in gnome_keyring_set_network_password_sync () from /usr/lib/libgnome-keyring.so.0
#10 0x080647cd in ?? ()
#11 0x08052696 in ?? ()
#12 0x08059b68 in ?? ()
#13 0x080589fd in ?? ()
#14 0x0805476e in ?? ()
#15 0x00685cec in ?? () from /lib/libglib-2.0.so.0
#16 0x00683dcf in ?? () from /lib/libglib-2.0.so.0
#17 0x0060a96e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#18 0x007b59de in clone () from /lib/tls/i686/cmov/libc.so.6

I have a feeling I didn't use the correct parameters to pull down the proper symbols, or maybe I don't have space, but it does show the shared objects on the stack which may help.

I also got the following trace from _usr_lib_gvfs_gvfsd-smb-browse.1000.crash:
--- source code stack trace ---
#0  0x00172422 in __kernel_vsyscall ()
#1  0x008a7641 in raise () from /lib/tls/i686/cmov/libc.so.6
#2  0x008aaa72 in abort () from /lib/tls/i686/cmov/libc.so.6
#3  0x00815dd3 in g_assertion_message () from /lib/libglib-2.0.so.0
#4  0x0081642d in g_assertion_message_expr () from /lib/libglib-2.0.so.0
#5  0x00e82802 in ?? () from /usr/lib/libgnome-keyring.so.0
#6  0x00e81b55 in ?? () from /usr/lib/libgnome-keyring.so.0
#7  0x00e828fc in ?? () from /usr/lib/libgnome-keyring.so.0
#8  0x00e835b1 in ?? () from /usr/lib/libgnome-keyring.so.0
#9  0x00e8ba16 in gnome_keyring_set_network_password_sync () from /usr/lib/libgnome-keyring.so.0
#10 0x08061d5d in ?? ()
#11 0x080507e8 in ?? ()
#12 0x08058198 in ?? ()
#13 0x0805702d in ?? ()
#14 0x08052d9e in ?? ()
#15 0x0081acec in ?? () from /lib/libglib-2.0.so.0
#16 0x00818dcf in ?? () from /lib/libglib-2.0.so.0
#17 0x00ccd96e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#18 0x0094a9de in clone () from /lib/tls/i686/cmov/libc.so.6