[ovs-dev] [PATCH v3] datapath-windows: Solved BSOD when uninstalling the driver (race condition)
Sorin Vinturis
svinturis at cloudbasesolutions.com
Tue Apr 7 16:35:54 UTC 2015
The BSOD occurred because the FilterAttach routine released the switch
context, while there were IRPs in processing.
The solution was to add a reference count to prevent premature deallocation of the
global switch context structure, gOvsSwitchContext.
Signed-off-by: Sorin Vinturis <svinturis at cloudbasesolutions.com>
Reported-by: Alin Gabriel Serdean <aserdean at cloudbasesolutions.com>
Reported-at: https://github.com/openvswitch/ovs-issues/issues/58
Acked-by: Eitan Eliahu <eliahue at vmware.com>
---
datapath-windows/ovsext/Datapath.c | 12 ++++++--
datapath-windows/ovsext/Switch.c | 56 ++++++++++++++++++++++++++++++++++++++
datapath-windows/ovsext/Switch.h | 6 +++-
3 files changed, 71 insertions(+), 3 deletions(-)
diff --git a/datapath-windows/ovsext/Datapath.c b/datapath-windows/ovsext/Datapath.c
index 8eb13f1..b692225 100644
--- a/datapath-windows/ovsext/Datapath.c
+++ b/datapath-windows/ovsext/Datapath.c
@@ -701,8 +701,13 @@ OvsDeviceControl(PDEVICE_OBJECT deviceObject,
/* Check if the extension is enabled. */
if (NULL == gOvsSwitchContext) {
- status = STATUS_DEVICE_NOT_READY;
- goto done;
+ status = STATUS_NOT_FOUND;
+ goto exit;
+ }
+
+ if (!OvsAcquireSwitchContext()) {
+ status = STATUS_NOT_FOUND;
+ goto exit;
}
/* Concurrent netlink operations are not supported. */
@@ -874,6 +879,9 @@ OvsDeviceControl(PDEVICE_OBJECT deviceObject,
status = InvokeNetlinkCmdHandler(&usrParamsCtx, nlFamilyOps, &replyLen);
done:
+ OvsReleaseSwitchContext(gOvsSwitchContext);
+
+exit:
KeMemoryBarrier();
instance->inUse = 0;
diff --git a/datapath-windows/ovsext/Switch.c b/datapath-windows/ovsext/Switch.c
index a228d8e..94565a6 100644
--- a/datapath-windows/ovsext/Switch.c
+++ b/datapath-windows/ovsext/Switch.c
@@ -42,6 +42,12 @@ extern PNDIS_SPIN_LOCK gOvsCtrlLock;
extern NDIS_HANDLE gOvsExtDriverHandle;
extern NDIS_HANDLE gOvsExtDriverObject;
+/*
+ * Reference count used to prevent premature deallocation of the global switch
+ * context structure, gOvsSwitchContext.
+ */
+volatile LONG gOvsSwitchContextRefCount = 1;
+
static NDIS_STATUS OvsCreateSwitch(NDIS_HANDLE ndisFilterHandle,
POVS_SWITCH_CONTEXT *switchContextOut);
static NDIS_STATUS OvsInitSwitchContext(POVS_SWITCH_CONTEXT switchContext);
@@ -420,6 +426,7 @@ OvsInitSwitchContext(POVS_SWITCH_CONTEXT switchContext)
switchContext->isActivateFailed = FALSE;
switchContext->dpNo = OVS_DP_NUMBER;
ovsTimeIncrementPerTick = KeQueryTimeIncrement() / 10000;
+
OVS_LOG_TRACE("Exit: Succesfully initialized switchContext: %p",
switchContext);
return NDIS_STATUS_SUCCESS;
@@ -428,6 +435,12 @@ OvsInitSwitchContext(POVS_SWITCH_CONTEXT switchContext)
static VOID
OvsUninitSwitchContext(POVS_SWITCH_CONTEXT switchContext)
{
+ OvsReleaseSwitchContext(switchContext);
+}
+
+VOID
+OvsDeleteSwitchContext(POVS_SWITCH_CONTEXT switchContext)
+{
OVS_LOG_TRACE("Enter: Delete switchContext:%p", switchContext);
/* We need to do cleanup for tunnel port here. */
@@ -450,6 +463,49 @@ OvsUninitSwitchContext(POVS_SWITCH_CONTEXT switchContext)
OVS_LOG_TRACE("Exit: Delete switchContext: %p", switchContext);
}
+VOID
+OvsReleaseSwitchContext(POVS_SWITCH_CONTEXT switchContext)
+{
+ LONG ref = 0;
+ LONG newRef = 0;
+ LONG icxRef = 0;
+
+ do {
+ ref = gOvsSwitchContextRefCount;
+ newRef = (0 == ref) ? 0 : ref - 1;
+ icxRef = InterlockedCompareExchange(&gOvsSwitchContextRefCount,
+ newRef,
+ ref);
+ } while (icxRef != ref);
+
+ if (ref == 1) {
+ OvsDeleteSwitchContext(switchContext);
+ }
+}
+
+BOOLEAN
+OvsAcquireSwitchContext(VOID)
+{
+ LONG ref = 0;
+ LONG newRef = 0;
+ LONG icxRef = 0;
+ BOOLEAN ret = FALSE;
+
+ do {
+ ref = gOvsSwitchContextRefCount;
+ newRef = (0 == ref) ? 0 : ref + 1;
+ icxRef = InterlockedCompareExchange(&gOvsSwitchContextRefCount,
+ newRef,
+ ref);
+ } while (icxRef != ref);
+
+ if (ref != 0) {
+ ret = TRUE;
+ }
+
+ return ret;
+}
+
/*
* --------------------------------------------------------------------------
* This function activates the switch by initializing it with all the runtime
diff --git a/datapath-windows/ovsext/Switch.h b/datapath-windows/ovsext/Switch.h
index 7960072..6ec34e1 100644
--- a/datapath-windows/ovsext/Switch.h
+++ b/datapath-windows/ovsext/Switch.h
@@ -202,7 +202,6 @@ OvsAcquireDatapathWrite(OVS_DATAPATH *datapath,
dispatch ? NDIS_RWL_AT_DISPATCH_LEVEL : 0);
}
-
static __inline VOID
OvsReleaseDatapath(OVS_DATAPATH *datapath,
LOCK_STATE_EX *lockState)
@@ -211,6 +210,11 @@ OvsReleaseDatapath(OVS_DATAPATH *datapath,
NdisReleaseRWLock(datapath->lock, lockState);
}
+BOOLEAN
+OvsAcquireSwitchContext(VOID);
+
+VOID
+OvsReleaseSwitchContext(POVS_SWITCH_CONTEXT switchContext);
PVOID OvsGetExternalVport();
--
1.9.0.msysgit.0
More information about the dev
mailing list