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Dmitry Lenev
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Fix for bug #51136 "Crash in pthread_rwlock_rdlock on
TEMPORARY + HANDLER + LOCK + SP". Server crashed when one: 1) Opened HANDLER or acquired global read lock 2) Then locked one or several temporary tables with LOCK TABLES statement (but no base tables). 3) Then issued any statement causing commit (explicit or implicit). 4) Issued statement which should have closed HANDLER or released global read lock. The problem was that when entering LOCK TABLES mode in the scenario described above we incorrectly set transactional MDL sentinel to zero. As result during commit all metadata locks were released (including lock for open HANDLER or global metadata shared lock). Indeed, attempt to release metadata lock for the second time which happened during HANLDER CLOSE or during release of GLR caused crash. This patch fixes problem by changing MDL_context's set_trans_sentinel() method to set sentinel to correct value (it should point to the most recent ticket). --BZR-- revision-id: [email protected] property-branch-nick: mysql-next-4284-bg51136 property-file-info: ld7:file_id65:sp1f-handler.test-20010406221832-gfvg6n4rp4py6lunazzembziuu5qxvi57:message95:Added test for bug #51136 "Crash in pthread_rwlock_rdlock on property-file-info: TEMPORARY + HANDLER + LOCK + SP".4:path30:mysql-test/include/handler.inced7:file_id65:sp1f-flush.result-20010323030458-fknoht4a4rohnwlkdtjcyx653fk3jumx7:message38:Updated test results (see flush.test).4:path25:mysql-test/r/flush.resulted7:file_id73:sp1f-innodb_handler.resul-20020821205505-jopsqbjuqwwxb5hvf3r2wn37vobunxru7:message47:Updated test results (see include/handler.inc).4:path34:mysql-test/r/handler_innodb.resulted7:file_id67:sp1f-handler.result-20010406221832-ybo3cgjo6qapqc6776ivjpdngwmk6plu7:message47:Updated test results (see include/handler.inc).4:path34:mysql-test/r/handler_myisam.resulted7:file_id63:sp1f-flush.test-20010323030458-7rtnbsox2xqacdijdaxl3yeinfs233eo7:message109:Added additional coverage for bug #51136 "Crash in property-file-info: pthread_rwlock_rdlock on TEMPORARY + HANDLER + LOCK + property-file-info: SP".4:path23:mysql-test/t/flush.tested7:file_id39:mdl.h-20080523121748-o4y2wcq3maotb9do-17:message321:When setting new value of transactional sentinel use property-file-info: pointer to the most recent ticket instead of value property-file-info: returned by MDL_context::mdl_savepoint(). property-file-info: This allows to handle correctly situation when the new property-file-info: value of sentinel should be the same as its current value property-file-info: (MDL_context::mdl_savepoint() returns NULL in this case).4:path9:sql/mdl.hee testament3-sha1: d133366368945a06f2a0f20b107cb4ace4bd9a21
1 parent 693fa6e commit 1146efb

6 files changed

Lines changed: 97 additions & 1 deletion

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‎mysql-test/include/handler.inc‎

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@@ -1681,3 +1681,25 @@ handler t1 close;
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--echo # Clean-up.
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drop function f1;
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drop tables t1, t2;
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--echo #
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--echo # Test for bug #51136 "Crash in pthread_rwlock_rdlock on TEMPORARY +
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--echo # HANDLER + LOCK + SP".
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--echo # Also see additional coverage for this bug in flush.test.
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--echo #
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--disable_warnings
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drop tables if exists t1, t2;
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--enable_warnings
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create table t1 (i int);
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create temporary table t2 (j int);
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handler t1 open;
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lock table t2 read;
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--echo # This commit should not release any MDL locks.
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commit;
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unlock tables;
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--echo # The below statement crashed before the bug fix as it
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--echo # has attempted to release metadata lock which was
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--echo # already released by commit.
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handler t1 close;
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drop tables t1, t2;

‎mysql-test/r/flush.result‎

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@@ -94,3 +94,20 @@ unlock tables;
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set global general_log= @old_general_log;
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set global read_only= @old_read_only;
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End of 5.1 tests
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#
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# Additional test for bug #51136 "Crash in pthread_rwlock_rdlock
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# on TEMPORARY + HANDLER + LOCK + SP".
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# Also see the main test for this bug in include/handler.inc.
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#
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drop tables if exists t1, t2;
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create table t1 (i int);
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create temporary table t2 (j int);
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flush tables with read lock;
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lock table t2 read;
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# This commit should not release any MDL locks.
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commit;
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# The below statement crashed before the bug fix as it
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# has attempted to release global shared metadata lock
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# which was already released by commit.
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unlock tables;
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drop tables t1, t2;

‎mysql-test/r/handler_innodb.result‎

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@@ -1667,3 +1667,21 @@ handler t1 close;
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# Clean-up.
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drop function f1;
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drop tables t1, t2;
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#
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# Test for bug #51136 "Crash in pthread_rwlock_rdlock on TEMPORARY +
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# HANDLER + LOCK + SP".
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# Also see additional coverage for this bug in flush.test.
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#
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drop tables if exists t1, t2;
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create table t1 (i int);
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create temporary table t2 (j int);
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handler t1 open;
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lock table t2 read;
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# This commit should not release any MDL locks.
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commit;
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unlock tables;
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# The below statement crashed before the bug fix as it
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# has attempted to release metadata lock which was
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# already released by commit.
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handler t1 close;
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drop tables t1, t2;

‎mysql-test/r/handler_myisam.result‎

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@@ -1664,6 +1664,24 @@ handler t1 close;
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drop function f1;
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drop tables t1, t2;
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#
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# Test for bug #51136 "Crash in pthread_rwlock_rdlock on TEMPORARY +
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# HANDLER + LOCK + SP".
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# Also see additional coverage for this bug in flush.test.
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#
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drop tables if exists t1, t2;
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create table t1 (i int);
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create temporary table t2 (j int);
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handler t1 open;
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lock table t2 read;
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# This commit should not release any MDL locks.
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commit;
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unlock tables;
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# The below statement crashed before the bug fix as it
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# has attempted to release metadata lock which was
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# already released by commit.
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handler t1 close;
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drop tables t1, t2;
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#
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# BUG #46456: HANDLER OPEN + TRUNCATE + DROP (temporary) TABLE, crash
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#
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CREATE TABLE t1 AS SELECT 1 AS f1;

‎mysql-test/t/flush.test‎

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Original file line numberDiff line numberDiff line change
@@ -203,3 +203,24 @@ set global general_log= @old_general_log;
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set global read_only= @old_read_only;
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--echo End of 5.1 tests
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--echo #
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--echo # Additional test for bug #51136 "Crash in pthread_rwlock_rdlock
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--echo # on TEMPORARY + HANDLER + LOCK + SP".
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--echo # Also see the main test for this bug in include/handler.inc.
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--echo #
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--disable_warnings
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drop tables if exists t1, t2;
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--enable_warnings
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create table t1 (i int);
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create temporary table t2 (j int);
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flush tables with read lock;
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lock table t2 read;
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--echo # This commit should not release any MDL locks.
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commit;
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--echo # The below statement crashed before the bug fix as it
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--echo # has attempted to release global shared metadata lock
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--echo # which was already released by commit.
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unlock tables;
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drop tables t1, t2;

‎sql/mdl.h‎

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@@ -501,7 +501,7 @@ class MDL_context
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void set_trans_sentinel()
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{
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m_trans_sentinel= mdl_savepoint();
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m_trans_sentinel= m_tickets.front();
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}
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MDL_ticket *trans_sentinel() const { return m_trans_sentinel; }
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