BUG#53657: Slave crashed with error 22 when trying to lock mutex

           at mf_iocache.c, line 1722

The slave crashed while two threads: IO thread and user thread
raced for the same mutex (the append_buffer_lock protecting the
relay log's IO_CACHE). The IO thread was trying to flush the
cache, and for that was grabbing the append_buffer_lock. 

However, the other thread was closing and reopening the relay log
when the IO thread tried to lock. Closing and reopening the log
includes destroying and reinitialising the IO_CACHE
mutex. Therefore, the IO thread tried to lock a destroyed mutex.

We fix this by backporting patch for BUG#50364 which fixed this
bug in mysql server 5.5+. The patch deploys missing
synchronization when flush_master_info is called and the relay
log is flushed by the IO thread. In detail the patch backports
revision (from mysql-trunk):
- luis.soares@sun.com-20100203165617-b1yydr0ee24ycpjm

This patch already includes the post-push fix also in BUG#50364:
- luis.soares@sun.com-20100222002629-0cijwqk6baxhj7gr

1 files changed, 3 insertions, 2 deletions

diff --git a/sql/rpl_mi.h b/sql/rpl_mi.h
index 93fb0a98198..023879f84fa 100644
--- a/sql/rpl_mi.h
+++ b/sql/rpl_mi.h
@@ -108,7 +108,8 @@ int init_master_info(Master_info* mi, const char* master_info_fname,
 		     bool abort_if_no_master_info_file,
 		     int thread_mask);
 void end_master_info(Master_info* mi);
-int flush_master_info(Master_info* mi, bool flush_relay_log_cache);
-
+int flush_master_info(Master_info* mi, 
+                      bool flush_relay_log_cache, 
+                      bool need_lock_relay_log);
 #endif /* HAVE_REPLICATION */
 #endif /* RPL_MI_H */