mirror/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2026-05-14 19:07:15 +02:00
Code Issues Projects Releases Packages Wiki 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 asynchronous 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.

mysql-test/r/shm.result:
  Add test case result for Bug#33899
mysql-test/t/shm.test:
  Add test case for Bug#33899
vio/viosocket.c:
  Also wait for close events.
This commit is contained in:
Davi Arnaut 2009-03-26 20:17:27 -03:00
commit 96e02e5716
3 changed files with 39 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

20
vio/viosocket.c
View file

@ -479,26 +479,28 @@ int vio_read_shared_memory(Vio * vio, gptr buf, int size)
int length;
int remain_local;
char *current_postion;
HANDLE events[2];
DBUG_ENTER("vio_read_shared_memory");
DBUG_PRINT("enter", ("sd: %d buf: 0x%lx size: %d", vio->sd, buf, size));
remain_local = size;
current_postion=buf;
events[0]= vio->event_server_wrote;
events[1]= vio->event_conn_closed;
do
{
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:
WAIT_OBJECT_0+0 - event from vio->event_server_wrote
WAIT_OBJECT_0+1 - event from vio->event_conn_closed. 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)
{
DBUG_RETURN(-1);
@ -537,19 +539,23 @@ int vio_write_shared_memory(Vio * vio, const gptr buf, int size)
{
int length;
uint remain;
HANDLE pos;
int sz;
char *current_postion;
HANDLE pos, events[2];
DBUG_ENTER("vio_write_shared_memory");
DBUG_PRINT("enter", ("sd: %d buf: 0x%lx size: %d", vio->sd, buf, size));
remain = size;
current_postion = buf;
events[0]= vio->event_server_read;
events[1]= vio->event_conn_closed;
while (remain != 0)
{
if (WaitForSingleObject(vio->event_server_read, vio->net->write_timeout*1000)
!= WAIT_OBJECT_0)
if (WaitForMultipleObjects(array_elements(events), events, FALSE,
vio->net->write_timeout*1000) != WAIT_OBJECT_0)
{
DBUG_RETURN(-1);
};