database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-08-07 00:04:31 +03:00
Code Activity

Bug#33899: Deadlock in mysql_real_query with shared memory connections

Browse Source 
The problem is that the read and write methods of the shared
memory transport (protocol) didn't react to asynchornous close
events, which could lead to a lock up as the client would wait
(until time out) for a server response that will never come.

The solution is to also wait for close events while waiting
for I/O from or to the server.

Bug report and patch submitted by: Armin Schöffmann
This commit is contained in:
Davi Arnaut
2009-03-26 20:25:10 -03:00
parent 9be507ca1f bfa198c2e7
commit 26f561d5d0
3 changed files with 41 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
mysql-test/r/shm.result
View File

@@ -2152,4 +2152,11 @@ Warnings:
Warning 1052 Column 'kundentyp' in group statement is ambiguous Warning 1052 Column 'kundentyp' in group statement is ambiguous
drop table t1; drop table t1;
mysqld is alive mysqld is alive
SET @max_allowed_packet= @@global.max_allowed_packet;
SET @net_buffer_length= @@global.net_buffer_length;
SET GLOBAL max_allowed_packet= 1024;
SET GLOBAL net_buffer_length= 1024;
ERROR 1153 (08S01) at line 1: Got a packet bigger than 'max_allowed_packet' bytes
SET GLOBAL max_allowed_packet= @max_allowed_packet;
SET GLOBAL net_buffer_length= @net_buffer_length;
End of 5.0 tests. End of 5.0 tests.

19
mysql-test/t/shm.test
View File

@@ -16,4 +16,23 @@ if (`SELECT '$shm' != 'ON'`){
# #
--exec $MYSQLADMIN --no-defaults --user=root --host=127.0.0.1 --port=$MASTER_MYPORT --shared-memory-base-name=HeyMrBaseNameXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX ping --exec $MYSQLADMIN --no-defaults --user=root --host=127.0.0.1 --port=$MASTER_MYPORT --shared-memory-base-name=HeyMrBaseNameXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX ping
#
# Bug #33899: Deadlock in mysql_real_query with shared memory connections
#
let $name= query_get_value("SHOW GLOBAL VARIABLES LIKE 'shared_memory_base_name'", Value, 1);
let $stmt= `SELECT REPEAT('a', 2048)`;
SET @max_allowed_packet= @@global.max_allowed_packet;
SET @net_buffer_length= @@global.net_buffer_length;
SET GLOBAL max_allowed_packet= 1024;
SET GLOBAL net_buffer_length= 1024;
--error 1
--exec echo SELECT '$stmt'| $MYSQL --protocol=memory --shared-memory-base-name=$name 2>&1
SET GLOBAL max_allowed_packet= @max_allowed_packet;
SET GLOBAL net_buffer_length= @net_buffer_length;
--echo End of 5.0 tests. --echo End of 5.0 tests.

22
vio/viosocket.c
View File

@@ -480,19 +480,22 @@ size_t vio_read_shared_memory(Vio * vio, uchar* buf, size_t size)
size_t length; size_t length;
size_t remain_local; size_t remain_local;
char *current_postion; char *current_postion;
HANDLE events[2];
DBUG_ENTER("vio_read_shared_memory"); DBUG_ENTER("vio_read_shared_memory");
DBUG_PRINT("enter", ("sd: %d buf: 0x%lx size: %d", vio->sd, (long) buf, DBUG_PRINT("enter", ("sd: %d buf: 0x%lx size: %d", vio->sd, (long) buf,
size)); size));
remain_local = size; remain_local = size;
current_postion=buf; current_postion=buf;
events[0]= vio->event_server_wrote;
events[1]= vio->event_conn_closed;
do do
{ {
if (vio->shared_memory_remain == 0) if (vio->shared_memory_remain == 0)
{ {
HANDLE events[2];
events[0]= vio->event_server_wrote;
events[1]= vio->event_conn_closed;
/* /*
WaitForMultipleObjects can return next values: WaitForMultipleObjects can return next values:
WAIT_OBJECT_0+0 - event from vio->event_server_wrote WAIT_OBJECT_0+0 - event from vio->event_server_wrote
@@ -500,7 +503,7 @@ size_t vio_read_shared_memory(Vio * vio, uchar* buf, size_t size)
anything anything
WAIT_ABANDONED_0 and WAIT_TIMEOUT - fail. We can't read anything WAIT_ABANDONED_0 and WAIT_TIMEOUT - fail. We can't read anything
*/ */
if (WaitForMultipleObjects(2, (HANDLE*)&events,FALSE, if (WaitForMultipleObjects(array_elements(events), events, FALSE,
vio->net->read_timeout*1000) != WAIT_OBJECT_0) vio->net->read_timeout*1000) != WAIT_OBJECT_0)
{ {
DBUG_RETURN(-1); DBUG_RETURN(-1);
@@ -543,17 +546,22 @@ size_t vio_write_shared_memory(Vio * vio, const uchar* buf, size_t size)
size_t length, remain, sz; size_t length, remain, sz;
HANDLE pos; HANDLE pos;
const uchar *current_postion; const uchar *current_postion;
HANDLE events[2];
DBUG_ENTER("vio_write_shared_memory"); DBUG_ENTER("vio_write_shared_memory");
DBUG_PRINT("enter", ("sd: %d buf: 0x%lx size: %d", vio->sd, (long) buf, DBUG_PRINT("enter", ("sd: %d buf: 0x%lx size: %d", vio->sd, (long) buf,
size)); size));
remain = size; remain = size;
current_postion = buf; current_postion = buf;
events[0]= vio->event_server_read;
events[1]= vio->event_conn_closed;
while (remain != 0) while (remain != 0)
{ {
if (WaitForSingleObject(vio->event_server_read, if (WaitForMultipleObjects(array_elements(events), events, FALSE,
vio->net->write_timeout*1000) != vio->net->write_timeout*1000) != WAIT_OBJECT_0)
WAIT_OBJECT_0)
{ {
DBUG_RETURN((size_t) -1); DBUG_RETURN((size_t) -1);
} }