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Bug#13898343 THREAD LOOPS ENDLESSLY IN LF_PINBOX_PUT_PINS WHILE HOLDING

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LOCK_THREAD_COUNT

When using the performance schema file io instrumentation in MySQL 5.5,
a thread would loop forever inside lf_pinbox_put_pins, when disconnecting.
It would also hold LOCK_thread_count while doing so, effectively killing the
server.

The root cause of the loop in lf_pinbox_put_pins() is a leak of LF_PINS,
when used with the filename_hash LF_HASH table in the performance schema.

This fix contains the following changes:

1)
Added the missing call to lf_hash_search_unpin(), to prevent the leak.

2)
In mysys/lf_alloc-pin.c, there was some extra debugging code
(MY_LF_EXTRA_DEBUG) written to detect precisely this kind of issues,
but it was never used.
Replaced MY_LF_EXTRA_DEBUG with DBUG_OFF, so that leaks similar to this one
can be always detected in regular debug builds.

3)
Backported the fix for the following bug, from 5.6 to 5.5:
Bug#13417446 - 63339: INCORRECT FILE PATH IN PEFORMANCE_SCHEMA ON WINDOWS
This commit is contained in:
Marc Alff
2012-03-28 17:54:30 +02:00
parent 86ad81b3af
commit ea40710d0e
2 changed files with 35 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
mysys/lf_alloc-pin.c
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@ -211,13 +211,16 @@ void _lf_pinbox_put_pins(LF_PINS *pins)
LF_PINBOX *pinbox= pins->pinbox;
uint32 top_ver, nr;
nr= pins->link;
#ifdef MY_LF_EXTRA_DEBUG
#ifndef DBUG_OFF
{
/* This thread should not hold any pin. */
int i;
for (i= 0; i < LF_PINBOX_PINS; i++)
DBUG_ASSERT(pins->pin[i] == 0);
}
#endif
#endif /* DBUG_OFF */
/*
XXX this will deadlock if other threads will wait for
the caller to do something after _lf_pinbox_put_pins(),