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| author | Inaam Rana <inaam.rana@oracle.com> | 2012-03-15 11:53:30 -0400 |
|---|---|---|
| committer | Inaam Rana <inaam.rana@oracle.com> | 2012-03-15 11:53:30 -0400 |
| commit | a8217b7cd3e31c7ff5212b84b9736af689a5ad39 (patch) | |
| tree | b303a60ab468832985d978864483e9ea27b60ebe /storage | |
| parent | 7f84e70b8689c535828af7f696775c4391f20a66 (diff) | |
| download | mariadb-git-a8217b7cd3e31c7ff5212b84b9736af689a5ad39.tar.gz | |
Bug#13537504 VALGRIND: COND. JUMP/MOVE DEPENDS ON UNINITIALISED VALUES
IN OS_THREAD_EQ
rb://977
approved by: Marko Makela
rw_lock::writer_thread field contains the thread id of current x-holder
or wait-x thread. This field is un-initialized at lock creation and is
written to for the first time when an attempt is made to x-lock.
Current code considers ::writer_thread as valid memory region only when
the lock is held in x-mode (or there is an x-waiter). This is an
overkill and it generates valgrind warnings.
The fix is to consider ::writer_thread as valid memory region once it
has been written to.
Reasoning:
==========
The ::writer_thread can be safely considered valid because:
* We only ever do comparison with current calling threads id.
* We only ever do comparison when ::recursive flag is set
* We always unset ::recursive flag in x-unlock
* Same thread cannot be unlocking and attempting to lock at the same
time
* thread_id recycling is not an issue because before an id is recycled
the thread must leave innodb meaning it must release all locks meaning
it must unset ::recursive flag.
Diffstat (limited to 'storage')
| -rw-r--r-- | storage/innodb_plugin/ChangeLog | 6 | ||||
| -rw-r--r-- | storage/innodb_plugin/include/sync0rw.ic | 4 |
2 files changed, 6 insertions, 4 deletions
diff --git a/storage/innodb_plugin/ChangeLog b/storage/innodb_plugin/ChangeLog index b43aed5cc06..416227c84c3 100644 --- a/storage/innodb_plugin/ChangeLog +++ b/storage/innodb_plugin/ChangeLog @@ -1,3 +1,9 @@ +2012-03-15 The InnoDB Team + + * include/sync0rw.ic: + Fix Bug#13537504 VALGRIND: COND. JUMP/MOVE DEPENDS ON + UNINITIALISED VALUES IN OS_THREAD_EQ + 2012-03-08 The InnoDB Team * btr/btr0pcur.c: diff --git a/storage/innodb_plugin/include/sync0rw.ic b/storage/innodb_plugin/include/sync0rw.ic index 5eb3d017eca..cd997febc30 100644 --- a/storage/innodb_plugin/include/sync0rw.ic +++ b/storage/innodb_plugin/include/sync0rw.ic @@ -564,8 +564,6 @@ rw_lock_x_unlock_func( if (lock->lock_word == 0) { /* Last caller in a possible recursive chain. */ lock->recursive = FALSE; - UNIV_MEM_INVALID(&lock->writer_thread, - sizeof lock->writer_thread); } #ifdef UNIV_SYNC_DEBUG @@ -606,8 +604,6 @@ rw_lock_x_unlock_direct( if (lock->lock_word == 0) { lock->recursive = FALSE; - UNIV_MEM_INVALID(&lock->writer_thread, - sizeof lock->writer_thread); } #ifdef UNIV_SYNC_DEBUG |