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Fix race condition in session.cc

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The dummy session was unnecessarily modified by multiple threads at the
same time. The state of the dummy session must not change once it's been
set at startup.
This commit is contained in:
Markus Mäkelä
2018-08-13 01:12:01 +03:00
parent 2852530893
commit f90b8cdafb
1 changed files with 17 additions and 14 deletions
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31
server/core/session.cc
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@ -58,7 +58,22 @@ static uint64_t next_session_id = 1;
static uint32_t retain_last_statements = 0;
static session_dump_statements_t dump_statements = SESSION_DUMP_STATEMENTS_NEVER;
static struct session session_dummy_struct;
namespace
{
static struct session dummy_session()
{
struct session session = {};
session.ses_chk_top = CHK_NUM_SESSION;
session.ses_chk_tail = CHK_NUM_SESSION;
session.state = SESSION_STATE_DUMMY;
session.refcount = 1;
return session;
}
}
static struct session session_dummy_struct = dummy_session();
static void session_initialize(void *session);
static int session_setup_filters(MXS_SESSION *session);
@ -237,19 +252,7 @@ static MXS_SESSION* session_alloc_body(SERVICE* service, DCB* client_dcb,
MXS_SESSION *
session_set_dummy(DCB *client_dcb)
{
MXS_SESSION *session;
session = &session_dummy_struct;
session->ses_chk_top = CHK_NUM_SESSION;
session->ses_chk_tail = CHK_NUM_SESSION;
session->service = NULL;
session->client_dcb = NULL;
memset(&session->stats, 0, sizeof(MXS_SESSION_STATS));
session->stats.connect = 0;
session->state = SESSION_STATE_DUMMY;
session->refcount = 1;
session->ses_id = 0;
MXS_SESSION* session = &session_dummy_struct;
client_dcb->session = session;
return session;
}