Description:
Hi,
The symptom of this bug is similar as Bug #68008. But their root cause is very different. I don't know whether this one affects 5.6.9.
When having the following configuration settings in option files:
#my.cnf
loose-enable-performance-schema
performance_schema_events_waits_history_long_size=0
The server crashes with the log message:
Floating point exception (core dumped)
The root cause is the modular operation in the following function:
/* storage/perfschema/pfs_events_waits.cc */
121 void insert_events_waits_history_long(PFS_events_waits *wait)
122 {
123 uint index= PFS_atomic::add_u32(&events_waits_history_long_index, 1);
124
125 index= index % events_waits_history_long_size;
126 if (index == 0)
127 events_waits_history_long_full= true;
128
129 /* See related comment in insert_events_waits_history. */
130 copy_events_waits(&events_waits_history_long_array[index], wait);
131 }
The back-trace from GDB is attached as follows:
(gdb) r
Starting program: /home/tianyin/mysql-5.5.28/usr/local/mysql/bin/mysqld
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7ffff6793700 (LWP 17817)]
[Thread 0x7ffff6793700 (LWP 17817) exited]
Program received signal SIGFPE, Arithmetic exception.
0x000000000086bbc0 in insert_events_waits_history_long (wait=0x7fffdb8352e8) at /home/tianyin/source_code/mysql-5.5.28/storage/perfschema/pfs_events_waits.cc:125
125 index= index % events_waits_history_long_size;
(gdb) bt
#0 0x000000000086bbc0 in insert_events_waits_history_long (wait=0x7fffdb8352e8) at /home/tianyin/source_code/mysql-5.5.28/storage/perfschema/pfs_events_waits.cc:125
#1 0x000000000086ac74 in end_mutex_wait_v1 (locker=0x7fffdb8352d8, rc=0) at /home/tianyin/source_code/mysql-5.5.28/storage/perfschema/pfs.cc:1629
#2 0x0000000000845f8b in inline_mysql_mutex_lock (that=0x10f5760, src_file=0xb0d588 "/home/tianyin/source_code/mysql-5.5.28/mysys/my_open.c", src_line=137)
at /home/tianyin/source_code/mysql-5.5.28/include/mysql/psi/mysql_thread.h:621
#3 0x000000000084621c in my_register_filename (fd=7, FileName=0x7fffffffd990 "/home/tianyin/mysql-5.5.28/usr/local/mysql/share/english/errmsg.sys",
type_of_file=FILE_BY_OPEN, error_message_number=29, MyFlags=0) at /home/tianyin/source_code/mysql-5.5.28/mysys/my_open.c:137
#4 0x000000000084604e in my_open (FileName=0x7fffffffd990 "/home/tianyin/mysql-5.5.28/usr/local/mysql/share/english/errmsg.sys", Flags=0, MyFlags=0)
at /home/tianyin/source_code/mysql-5.5.28/mysys/my_open.c:52
#5 0x00000000006e2759 in inline_mysql_file_open (key=9, src_file=0xaa1010 "/home/tianyin/source_code/mysql-5.5.28/sql/derror.cc", src_line=119,
filename=0x7fffffffd990 "/home/tianyin/mysql-5.5.28/usr/local/mysql/share/english/errmsg.sys", flags=0, myFlags=0)
at /home/tianyin/source_code/mysql-5.5.28/include/mysql/psi/mysql_file.h:1046
#6 0x00000000006e2bb1 in read_texts (file_name=0xaa1000 "errmsg.sys", language=0xa4ee60 "english", point=0x7fffffffdde0, error_messages=728)
at /home/tianyin/source_code/mysql-5.5.28/sql/derror.cc:116
#7 0x00000000006e2a16 in init_errmessage () at /home/tianyin/source_code/mysql-5.5.28/sql/derror.cc:70
#8 0x0000000000548070 in init_common_variables () at /home/tianyin/source_code/mysql-5.5.28/sql/mysqld.cc:3360
#9 0x0000000000549636 in mysqld_main (argc=30, argv=0x10fbe48) at /home/tianyin/source_code/mysql-5.5.28/sql/mysqld.cc:4397
#10 0x0000000000543f24 in main (argc=1, argv=0x7fffffffe1d8) at /home/tianyin/source_code/mysql-5.5.28/sql/main.cc:25
Thanks,
Tianyin
How to repeat:
Add the following two lines in the configuration file my.cnf,
#/etc/mysql/my.cnf
loose-enable-performance-schema
performance_schema_events_waits_history_long_size=0
then start the mysqld, and you can see the crash:
$ ./bin/mysqld
Floating point exception (core dumped)
Suggested fix:
Similar as Bug #68008,
I can think about two workaround:
1. Check the value, i.e., events_waits_history_long_size, in the "insert_events_waits_history_long" function;
2. Abandon the settings "performance_schema_events_waits_history_long_size=0" in the parsing function.
