從48往後的版本的changelog中收集，還沒細看，先整理下來！
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fixed in 5.1.49：
Bug#50364
Replication: FLUSH LOGS could in some circumstances crash the server. This occurred because the I/O thread could concurrently access the relay log I/O cache while another thread was performing the FLUSH LOGS,
which closes and reopens the relay log and, while doing so, initializes (or re-initializes) its I/O cache. This could cause problems if some other thread (in this case, the I/O thread) is accessing it at the same time. Now the thread performing the FLUSH LOGS
takes a lock on the relay log before actually flushing it
Bug#54041
A client could supply data in chunks to a prepared statement parameter other than of type TEXT or BLOB using the mysql_stmt_send_long_data() C API function (or COM_STMT_SEND_LONG_DATA command). This led to a
crash because other data types are not valid for long data.
Bug#42064
The server could crash with an out of memory error when trying to parse a query that was too long to fit in memory. Now the parser rejects such queries with an ER_OUT_OF_RESOURCES error.
fiexed in 5.1.50：
Bug#55581
The server could crash on shutdown, if started with --innodb-use-system-malloc=0.
Bug#54453
The database server could crash when renaming a table that had active transactions. (This issue only affected the database server when built for debugging.)
Bug#54408
The server could crash during the recovery phase of startup, if it previously crashed while inserting BLOB or other large columns that use off-page storage into an InnoDB table created with ROW_FORMAT=REDUNDANT or ROW_FORMAT=COMPACT.
Bug#54041
A client could supply data in chunks to a prepared statement parameter other than of type TEXT or BLOB using the mysql_stmt_send_long_data() C API function (or COM_STMT_SEND_LONG_DATA command). This led to a crash because other
data types are not valid for long data.
fiexed in 5.1.51:
Bug#46086
Partitioning: When the storage engine used to create a partitioned table was disabled, attempting to drop the table caused the server to crash.
fiexed in 5.1.55
Bug#58553
Issuing EXPLAIN EXTENDED for a query that would use condition pushdown could cause mysqld to crash.
Bug#58396
EXPLAIN could crash for queries that used GROUP_CONCAT().
Bug#57703
Unnecessary subquery evaluation in contexts such as statement preparation or view creation could cause a server crash.
Bug#57321
NULL geometry values could cause a crash in Item_func_spatial_collection::fix_length_and_dec.
Bug#51817
When mysqld printed crash dump information, it incorrectly indicated that some valid pointers were invalid