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BUG#21102971 data corruption on arm64

Browse source 
The root cause is that x86 has a stronger memory model than the ARM
processors. And the GCC builtins didn't issue the correct fences when
setting/unsetting the lock word. In particular during the mutex release.

The solution is rewriting atomic TAS operations: replace '__sync_' by
'__atomic_' if possible.

Reviewed-by: Sunny Bains      <sunny.bains@oracle.com>
Reviewed-by: Bin Su           <bin.x.su@oracle.com>
Reviewed-by: Debarun Banerjee <debarun.banerjee@oracle.com>
Reviewed-by: Krunal Bauskar   <krunal.bauskar@oracle.com>
RB: 9782
RB: 9665
RB: 9783
This commit is contained in:
Shaohua Wang 2015-08-10 16:31:05 +08:00
commit f59d68eeae
4 changed files with 131 additions and 33 deletions
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9
storage/innobase/include/sync0sync.ic
View file

@ -1,6 +1,6 @@
/*****************************************************************************
Copyright (c) 1995, 2009, Innobase Oy. All Rights Reserved.
Copyright (c) 1995, 2015, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2008, Google Inc.
Portions of this file contain modifications contributed and copyrighted by
@ -80,7 +80,7 @@ mutex_test_and_set(
mutex_t* mutex) /*!< in: mutex */
{
#if defined(HAVE_ATOMIC_BUILTINS)
return(os_atomic_test_and_set_byte(&mutex->lock_word, 1));
return(os_atomic_test_and_set(&mutex->lock_word));
#else
ibool ret;
@ -108,10 +108,7 @@ mutex_reset_lock_word(
mutex_t* mutex) /*!< in: mutex */
{
#if defined(HAVE_ATOMIC_BUILTINS)
/* In theory __sync_lock_release should be used to release the lock.
Unfortunately, it does not work properly alone. The workaround is
that more conservative __sync_lock_test_and_set is used instead. */
os_atomic_test_and_set_byte(&mutex->lock_word, 0);
os_atomic_clear(&mutex->lock_word);
#else
mutex->lock_word = 0;