4501 Vamsikrishna Bhagi 2012-10-18
Bug#14547920 I_MAIN.BUG13115401 CAUSING VALGRIND REPORT
FAILURE ON PB2
Issue: The test i_main.bug13115401 which was added to fix
the bug #13115401 has introduced a sproadic valgrind
failure report on pushbuild specific to yaSSL build.
It being a sporadic issue, it can be reproduced once
or twice when the command below is run for around
50 times.
perl mysql-test-run.pl --timer --debug-server
--force --comment=n_mix-debug --vardir=var-n_mix
--mysqld=--binlog-format=mixed
--experimental=collections/default.experimental
--skip-ndb
--skip-test-list=collections/disabled-per-push.list
--unit-tests --valgrind
--valgrind-option=--gen-suppressions=all
--valgrind-option=--show-reachable=yes
Solution: The problem arises on a multi-threaded scenario
when a thread tries to create a session object
from GetSessions() method as another thread is
already doing a creation. As the memory allocated
in first thread is overridden by memory allocated
by the second thread, the memory allocated by the
first thread will be a leak in this case. This is
because the yassl session instance is not thread
safe. In the current scenario a pointer is not
necessary as it is created from a singleton
method and actually adds to complexity by
allowing multiple allocations. Hence it is
replaced by a normal object. This will solve the
problem aroused in a multithreaded scenario.
******
Bug#14547920 I_MAIN.BUG13115401 CAUSING VALGRIND REPORT
FAILURE ON PB2
Issue: The test i_main.bug13115401 which was added to fix
the bug #13115401 has introduced a sporadic valgrind
failure report on pushbuild specific to yaSSL build.
Being a sporadic issue, it can be reproduced once
or twice when the command below is run for around
50 times.
perl mysql-test-run.pl --timer --debug-server
--force --comment=n_mix-debug --vardir=var-n_mix
--mysqld=--binlog-format=mixed
--experimental=collections/default.experimental
--skip-ndb
--skip-test-list=collections/disabled-per-push.list
--unit-tests --valgrind
--valgrind-option=--gen-suppressions=all
--valgrind-option=--show-reachable=yes
Solution: The problem arises on a multi-threaded scenario
when a thread tries to create a session object
from GetSessions() method as another thread is
already doing a creation. As the memory allocated
in first thread is overridden by memory allocated
by the second thread, the memory allocated by the
first thread will be a leak in this case. This is
because the yassl session instance is not thread
safe. To make this instance creation process
compatible with multi-threading, a new instance
is created by with the help of pthread_once,
which will essentially check if the function used
for creating an instance is already called
previously or not.
@ extra/yassl/src/yassl_int.cpp
Bug#14547920 I_MAIN.BUG13115401 CAUSING VALGRIND REPORT
FAILURE ON PB2
The return value of the method GetSession() is a pointer
*sessionsInstance which is created afterchecking if the
pointer is empty or not. But this results in a leak when a
thread execution clears the check condition
if (!sessionsInstance) as the allocation for another thread
is going on at sessionsInstance = NEW_YS Sessions.
Implementing this method with a pointer causes this
conflict. A pointer is not required in this case as the
allocation is done through a singleton creator and is also
adding a loophole in a multithreaded condition, hence it is
replaced with normal object Sessions::sessionsInstance.
******
Bug#14547920 I_MAIN.BUG13115401 CAUSING VALGRIND REPORT
FAILURE ON PB2
The return value of the method GetSession() is a pointer
*sessionsInstance which is created after checking if the
pointer is empty or not. But this results in a leak when a
thread execution clears the check condition
if (!sessionsInstance) as the allocation for another thread
is going on at sessionsInstance = NEW_YS Sessions. To make
this process thread safe, pthread_once method is used to
create an instance which will see to that session is
created only once in existing context(kindly refer C++
documentation for more details on pthread_once). Since
pthread_once takes only void returning functions as an
argument, a new function Session_initialize is implemented
to create a session. The check variable session_created is
refreshed after deleting the sessionInstance in yaSSL
cleanup. Since a session is being created only after the
old one is cleared, there will not be a memory leak.
modified:
extra/yassl/include/yassl_int.hpp
extra/yassl/src/yassl_int.cpp
4500 Amit Bhattacharya 2012-10-18
Removing the files to fix the issues
removed:
mysql-test/include/multi_table_del_sj.inc
mysql-test/include/multi_table_upd_sj.inc
mysql-test/r/multi_table_upd_del_sj.result
mysql-test/t/multi_table_upd_del_sj.test
=== modified file 'extra/yassl/include/yassl_int.hpp'
--- a/extra/yassl/include/yassl_int.hpp 2012-07-24 13:24:00 +0000
+++ b/extra/yassl/include/yassl_int.hpp 2012-10-18 05:32:59 +0000
@@ -278,13 +278,13 @@ public:
~Sessions();
+ friend void Session_initialize();
friend Sessions& GetSessions(); // singleton creator
private:
Sessions(const Sessions&); // hide copy
Sessions& operator=(const Sessions&); // and assign
};
-
#ifdef _POSIX_THREADS
typedef pthread_t THREAD_ID_T;
#else
=== modified file 'extra/yassl/src/yassl_int.cpp'
--- a/extra/yassl/src/yassl_int.cpp 2012-07-24 13:24:00 +0000
+++ b/extra/yassl/src/yassl_int.cpp 2012-10-18 05:32:59 +0000
@@ -17,15 +17,12 @@
* draft along with type conversion functions.
*/
+#include "pthread.h"
#include "runtime.hpp"
#include "yassl_int.hpp"
#include "handshake.hpp"
#include "timer.hpp"
-#ifdef _POSIX_THREADS
- #include "pthread.h"
-#endif
-
#ifdef HAVE_LIBZ
#include "zlib.h"
@@ -1564,17 +1561,22 @@ SSL_SESSION::~SSL_SESSION()
ysDelete(peerX509_);
}
-
static Sessions* sessionsInstance = 0;
+static pthread_once_t session_created= PTHREAD_ONCE_INIT;
+
+
+void Session_initialize()
+{
+ sessionsInstance = NEW_YS Sessions;
+}
+
Sessions& GetSessions()
{
- if (!sessionsInstance)
- sessionsInstance = NEW_YS Sessions;
+ pthread_once(&session_created, Session_initialize);
return *sessionsInstance;
}
-
static sslFactory* sslFactoryInstance = 0;
sslFactory& GetSSL_Factory()
@@ -2627,9 +2629,10 @@ extern "C" void yaSSL_CleanUp()
{
TaoCrypt::CleanUp();
yaSSL::ysDelete(yaSSL::sslFactoryInstance);
- yaSSL::ysDelete(yaSSL::sessionsInstance);
yaSSL::ysDelete(yaSSL::errorsInstance);
-
+ yaSSL::ysDelete(yaSSL::sessionsInstance);
+ yaSSL::session_created= PTHREAD_ONCE_INIT;
+
// In case user calls more than once, prevent seg fault
yaSSL::sslFactoryInstance = 0;
yaSSL::sessionsInstance = 0;
No bundle (reason: useless for push emails).
| Thread |
|---|
| • bzr push into mysql-5.6 branch (vamsikrishna.bhagi:4500 to 4501) Bug#14547920 | Vamsikrishna Bhagi | 18 Oct |
