#3 0x082d05ab in handle_segfault (sig=11) at mysqld.cc:2838
#4 <signal handler called>
#5 0x0881d10e in decimal_cmp (from1=0x0, from2=0x945d0f8) at decimal.c:1971
#6 0x082114e3 in my_decimal_cmp (a=0x0, b=0x945d0f8) at my_decimal.h:438
#7 0x0823e58d in Arg_comparator::compare_decimal (this=0x945cecc) at item_cmpfunc.cc:1090
#8 0x0822374a in Arg_comparator::compare (this=0x945cecc) at item_cmpfunc.h:72
#9 0x08240614 in Item_func_gt::val_int (this=0x945ce48) at item_cmpfunc.cc:1884
#10 0x08208738 in Item::send (this=0x945ce48, protocol=0x93ee7e4, buffer=0xae898060) at item.cc:5971
#11 0x082b8b56 in select_send::send_data (this=0x945d000, items=...) at sql_class.cc:1996
#12 0x08356416 in JOIN::exec (this=0x946ac68) at sql_select.cc:2115
#13 0x08358e45 in mysql_select (thd=0x93ee4b8, rref_pointer_array=0x93f0044, tables=0x0,
wild_num=0, fields=..., conds=0x0, og_num=0, order=0x0, group=0x0, having=0x0, proc_param=0x0,
select_options=2147764736, result=0x945d000, unit=0x93efc28, select_lex=0x93eff08)
at sql_select.cc:2931
#14 0x08350b5f in handle_select (thd=0x93ee4b8, lex=0x93efbcc, result=0x945d000,
setup_tables_done_option=0) at sql_select.cc:284
#15 0x082ec098 in execute_sqlcom_select (thd=0x93ee4b8, all_tables=0x0) at sql_parse.cc:5148
#16 0x082e3474 in mysql_execute_command (thd=0x93ee4b8) at sql_parse.cc:2281
#17 0x082ee6d3 in mysql_parse (thd=0x93ee4b8, rawbuf=0x945cc08 "SELECT UNIX_TIMESTAMP('abc') > 0",
length=32, found_semicolon=0xae899234) at sql_parse.cc:6149
#18 0x082e10d6 in dispatch_command (command=COM_QUERY, thd=0x93ee4b8, packet=0x9447329 "",
packet_length=32) at sql_parse.cc:1227
#19 0x082e0580 in do_command (thd=0x93ee4b8) at sql_parse.cc:922
#20 0x082dd545 in handle_one_connection (arg=0x93ee4b8) at sql_connect.cc:1193
#21 0xb76aeb25 in start_thread () from /lib/libpthread.so.0

bzr version-info
revision-id: <email address hidden>
date: 2012-01-25 22:05:20 +0400
build-date: 2012-01-29 21:29:29 +0400
revno: 3395
branch-nick: maria-5.3

Also reproducible on MariaDB 5.3.2, 5.3.3, 5.5.
Could not reproduce in MariaDB 5.2, MySQL 5.1.60, 5.5.20, 5.6.4.

Minimal optimizer_switch: none required
Full optimizer_switch: index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off,table_elimination=on

Test case:

SELECT UNIX_TIMESTAMP('abc') > 0;