MySQL Bugs: #71566: MySQL 5.5.35 Segfault

Bug #71566	MySQL 5.5.35 Segfault
Submitted:	3 Feb 2014 15:35	Modified:	24 Aug 2014 20:16
Reporter:	Steven Johnson	Email Updates:
Status:	No Feedback	Impact on me:	None
Category:	MySQL Server: Merge storage engine	Severity:	S2 (Serious)
Version:	5.5.35	OS:	Linux (RHEL 6.4)
Assigned to:		CPU Architecture:	Any

Description:
We have had several segfaults recently on a RHEL 6.4 server running MySQL 5.5.35. We have not found any existing bugs that show this issue or any fixes that address this issue in 5.5.36, as such we are raising this as a bug. 

See below for log output:

07:06:03 UTC - mysqld got signal 11 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.
We will try our best to scrape up some info that will hopefully help
diagnose the problem, but since we have already crashed, 
something is definitely wrong and this may fail.

key_buffer_size=3221225472
read_buffer_size=131072
max_used_connections=21
max_threads=1100
thread_count=13
connection_count=13
It is possible that mysqld could use up to 
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 5552003 K  bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x2db5100
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong...
stack_bottom = 7f1375becd98 thread_stack 0x40000
/usr/libexec/mysqld(my_print_stacktrace+0x2e)[0x78b35e]
/usr/libexec/mysqld(handle_fatal_signal+0x493)[0x674343]
/lib64/libpthread.so.0[0x30c780f500]
/usr/libexec/mysqld(mi_reset+0x2a)[0x7bb5da]
/usr/libexec/mysqld(myrg_reset+0x38)[0x796b48]
/usr/libexec/mysqld(_Z24mark_tmp_table_for_reuseP5TABLE+0x18)[0x54a378]
/usr/libexec/mysqld(_Z19close_thread_tablesP3THD+0xca)[0x54f32a]
/usr/libexec/mysqld(_Z21mysql_execute_commandP3THD+0x1b9)[0x581cd9]
/usr/libexec/mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x1bb)[0x5862eb]
/usr/libexec/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x1c9c)[0x58873c]
/usr/libexec/mysqld(_Z24do_handle_one_connectionP3THD+0xd2)[0x619032]
/usr/libexec/mysqld(handle_one_connection+0x50)[0x619140]
/lib64/libpthread.so.0[0x30c7807851]
/lib64/libc.so.6(clone+0x6d)[0x30c70e890d]

Trying to get some variables.
Some pointers may be invalid and cause the dump to abort.
Query (7f12d8004bc0): is an invalid pointer
Connection ID (thread ID): 530286
Status: NOT_KILLED

How to repeat:
We are currently unaware of how to repeat this segfault.

We appear to have found the cause of the issue. 

The variable "table_open_cache" was erroneously set to a very small value. 

Setting this to the correct value appears to have mitigated the segfaults.

Thank you for the report.

Backtrace is not really useful unfortunately. Please try to find out what leads to segfault in your case and, at least, explain why you choose "Merge table engine" category for this bug. Do you use Merge tables when the issue happens?

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".