Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Won't Fix
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10.2, 10.3, 10.4
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None
Description
In innodb_init() there's wait for thd_destructor_thread startup:
mysql_thread_create(thd_destructor_thread_key,
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&thd_destructor_thread,
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NULL, thd_destructor_proxy, NULL);
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while (!my_atomic_loadptr_explicit(reinterpret_cast<void**>
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(&srv_running),
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MY_MEMORY_ORDER_RELAXED))
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os_thread_sleep(20);
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However if thd_destructor_thread dies before loadptr, this becomes dead loop. E.g. server shutdown during InnoDB initialisation?
Second problem is in innobase_end(). In fact time to time I get crashes here.
st_my_thread_var* running = reinterpret_cast<st_my_thread_var*>(
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my_atomic_loadptr_explicit(
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reinterpret_cast<void**>(&srv_running),
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MY_MEMORY_ORDER_RELAXED));
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if (!abort_loop && running) {
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// may be UNINSTALL PLUGIN statement
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running->abort = 1;
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mysql_cond_broadcast(running->current_cond);
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}
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If thd_destructor_thread dies between atomic load and mysql_cond_broadcast(), it'll attempt to broadcast on destroyed cond via freed "running" pointer.
The problem is much broader though. Background threads creation/destruction synchronisation is in sorry state. So we need to implement some universally applicable framework.
Attachments
Issue Links
- relates to
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MDEV-16264 Implement a common work queue for InnoDB background tasks
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- Closed
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