Commit 68249bbb authored by guilhem@mysql.com's avatar guilhem@mysql.com

Merge gbichot@bk-internal.mysql.com:/home/bk/mysql-4.0

into mysql.com:/home/mysql_src/mysql-4.0
parents 0c3109fc 9275a701
No related merge requests found
......@@ -1544,7 +1544,6 @@ bool MYSQL_LOG::write(THD *thd,const char *query, uint query_length,
void MYSQL_LOG:: wait_for_update(THD* thd, bool master_or_slave)
{
safe_mutex_assert_owner(&LOCK_log);
const char* old_msg = thd->enter_cond(&update_cond, &LOCK_log,
master_or_slave ?
"Has read all relay log; waiting for \
......
......@@ -299,8 +299,18 @@ void THD::awake(bool prepare_to_die)
exits the cond in the time between read and broadcast, but that is
ok since all we want to do is to make the victim thread get out
of waiting on current_cond.
If we see a non-zero current_cond: it cannot be an old value (because
then exit_cond() should have run and it can't because we have mutex); so
it is the true value but maybe current_mutex is not yet non-zero (we're
in the middle of enter_cond() and there is a "memory order
inversion"). So we test the mutex too to not lock 0.
Note that there is a small chance we fail to kill. If victim has locked
current_mutex, and hasn't entered enter_cond(), then we don't know it's
going to wait on cond. Then victim goes into its cond "forever" (until
we issue a second KILL). True we have set its thd->killed but it may not
see it immediately and so may have time to reach the cond_wait().
*/
if (mysys_var->current_cond)
if (mysys_var->current_cond && mysys_var->current_mutex)
{
pthread_mutex_lock(mysys_var->current_mutex);
pthread_cond_broadcast(mysys_var->current_cond);
......
......@@ -539,6 +539,7 @@ public:
const char* msg)
{
const char* old_msg = proc_info;
safe_mutex_assert_owner(mutex);
mysys_var->current_mutex = mutex;
mysys_var->current_cond = cond;
proc_info = msg;
......
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