Another one:
#0 0xb7fbf424 in __kernel_vsyscall () No symbol table info available. #1 0xb7e7a640 in raise () from /lib/i686/cmov/libc.so.6 No symbol table info available. #2 0xb7e7c018 in abort () from /lib/i686/cmov/libc.so.6 No symbol table info available. #3 0x080ee9a5 in default_fatal_finish (type=<value optimized out>, status=0) at failures.c:161 backtrace = 0x8282480 "imap [0x80ee991] -> imap [0x80eea12] -> imap [0x80ee399] -> imap [0x80b50eb] -> imap(shared_storage_get_namespace+0x2bf) [0x8075fff] -> imap [0x80757d7] -> imap [0x8063034] -> imap(cmd_list_full+0x514"... #4 0x080eea12 in i_internal_fatal_handler (type=LOG_TYPE_PANIC, status=0, fmt=0x810632c "file %s: line %d (%s): assertion failed: (%s)", args=0xbfbda674 "\017\v\021\b\036") at failures.c:441 No locals. #5 0x080ee399 in i_panic (format=0x810632c "file %s: line %d (%s): assertion failed: (%s)") at failures.c:208 No locals. #6 0x080b50eb in mail_user_init (username=0x829854e "") at mail-user.c:30 user = <value optimized out> pool = <value optimized out> __PRETTY_FUNCTION__ = "mail_user_init" #7 0x08075fff in shared_storage_get_namespace (_storage=0x82929d0, _name=0xbfbda724, ns_r=0xbfbda728) at shared-storage.c:224 user = (struct mail_user *) 0x828e270 ns = (struct mail_namespace *) 0x0 owner = <value optimized out> domain = 0x0 username = 0x829854e "" userdomain = 0x829854e "" name = 0x810fc97 "INBOX" p = <value optimized out> dest = <value optimized out> error = <value optimized out> prefix = (string_t *) 0x82823b0 location = <value optimized out> ret = <value optimized out> static_tab = {{key = 117 'u', value = 0x0, long_key = 0x8110b32 "user"}, {key = 110 'n', value = 0x0, long_key = 0x8109830 "username"}, { key = 100 'd', value = 0x0, long_key = 0x8109839 "domain"}, {key = 104 'h', value = 0x0, long_key = 0x8109807 "home"}, {key = 0 '\0', value = 0x0, long_key = 0x0}} __PRETTY_FUNCTION__ = "shared_storage_get_namespace" #8 0x080757d7 in shared_list_join_refpattern (list=0x8292dd8, ref=0x8298548 "#User/", pattern=0x8298550 "*") at shared-list.c:148 ns = <value optimized out> ns_ref = 0x829854e "" prefix = 0x8292998 "#User/" #9 0x08063034 in cmd_list_continue (cmd=0x8293448) at cmd-list.c:672 _data_stack_cur_id = 4 ctx = (struct cmd_list_context *) 0x82934e0 #10 0x08063a04 in cmd_list_full (cmd=0x8293448, lsub=false) at cmd-list.c:903 client = (struct client *) 0x82931b8 args = (const struct imap_arg *) 0x82984e8 arg = <value optimized out> ctx = (struct cmd_list_context *) 0x82934e0 patterns = {arr = {buffer = 0x8293508, element_size = 4}, v = 0x8293508, v_modifiable = 0x8293508} pattern = 0x8298550 "*" #11 0x08063d09 in cmd_list (cmd=0x8293448) at cmd-list.c:918 No locals. #12 0x0806700c in client_command_input (cmd=0x8293448) at client.c:603 client = (struct client *) 0x82931b8 command = <value optimized out> __PRETTY_FUNCTION__ = "client_command_input" #13 0x080670a9 in client_command_input (cmd=0x8293448) at client.c:652 client = (struct client *) 0x82931b8 command = <value optimized out> __PRETTY_FUNCTION__ = "client_command_input" #14 0x080676ed in client_handle_input (client=0x82931b8) at client.c:693 _data_stack_cur_id = 3 ret = <value optimized out> remove_io = <value optimized out> handled_commands = false #15 0x08067ba3 in client_input (client=0x82931b8) at client.c:748 cmd = <value optimized out> output = (struct ostream *) 0x829336c bytes = <value optimized out> __PRETTY_FUNCTION__ = "client_input" #16 0x080f73a0 in io_loop_handler_run (ioloop=0x828aae0) at ioloop-epoll.c:208 ctx = (struct ioloop_handler_context *) 0x828abe8 event = (const struct epoll_event *) 0x828ac28 list = (struct io_list *) 0x82933f0 io = (struct io_file *) 0x82933c8 tv = {tv_sec = 1799, tv_usec = 999778} t_id = 2 msecs = <value optimized out> ret = 1 i = 0 j = 0 call = <value optimized out> #17 0x080f6830 in io_loop_run (ioloop=0x828aae0) at ioloop.c:338 No locals. #18 0x080704c5 in main (argc=Cannot access memory at address 0x4c2f ) at main.c:320