There is a possible race condition when hv_utils starts to load immediately
after hv_vmbus is loading - null pointer error could happen.
This patch added wait/completion to ensure all channels are ready before
vmbus loading completes. So another module won't have any uninitialized channel.
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/module.h>
+#include <linux/completion.h>
#include "osd.h"
#include "logging.h"
#include "vmbus_private.h"
#include "osd.h"
#include "logging.h"
#include "vmbus_private.h"
+
+DECLARE_COMPLETION(hv_channel_ready);
+
+/*
+ * Count initialized channels, and ensure all channels are ready when hv_vmbus
+ * module loading completes.
+ */
+static void count_hv_channel(void)
+{
+ static int counter;
+ unsigned long flags;
+
+ spin_lock_irqsave(&gVmbusConnection.channel_lock, flags);
+ if (++counter == MAX_MSG_TYPES)
+ complete(&hv_channel_ready);
+ spin_unlock_irqrestore(&gVmbusConnection.channel_lock, flags);
+}
+
+
/*
* VmbusChannelProcessOffer - Process the offer by creating a channel/device
* associated with this offer
/*
* VmbusChannelProcessOffer - Process the offer by creating a channel/device
* associated with this offer
* can cleanup properly
*/
newChannel->State = CHANNEL_OPEN_STATE;
* can cleanup properly
*/
newChannel->State = CHANNEL_OPEN_STATE;
- while (cnt != MAX_MSG_TYPES) {
+ /* Open IC channels */
+ for (cnt = 0; cnt < MAX_MSG_TYPES; cnt++) {
if (memcmp(&newChannel->OfferMsg.Offer.InterfaceType,
&hv_cb_utils[cnt].data,
if (memcmp(&newChannel->OfferMsg.Offer.InterfaceType,
&hv_cb_utils[cnt].data,
- sizeof(struct hv_guid)) == 0) {
+ sizeof(struct hv_guid)) == 0 &&
+ VmbusChannelOpen(newChannel, 2 * PAGE_SIZE,
+ 2 * PAGE_SIZE, NULL, 0,
+ hv_cb_utils[cnt].callback,
+ newChannel) == 0) {
+ hv_cb_utils[cnt].channel = newChannel;
- hv_cb_utils[cnt].log_msg);
-
- if (VmbusChannelOpen(newChannel, 2 * PAGE_SIZE,
- 2 * PAGE_SIZE, NULL, 0,
- hv_cb_utils[cnt].callback,
- newChannel) == 0)
- hv_cb_utils[cnt].channel = newChannel;
+ hv_cb_utils[cnt].log_msg);
+ count_hv_channel();
void vmbus_child_driver_unregister(struct driver_context *driver_ctx);
void vmbus_get_interface(struct vmbus_channel_interface *interface);
void vmbus_child_driver_unregister(struct driver_context *driver_ctx);
void vmbus_get_interface(struct vmbus_channel_interface *interface);
+extern struct completion hv_channel_ready;
+
#include <linux/pci.h>
#include <linux/dmi.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/dmi.h>
#include <linux/slab.h>
+#include <linux/completion.h>
#include "version_info.h"
#include "osd.h"
#include "logging.h"
#include "version_info.h"
#include "osd.h"
#include "logging.h"
vmbus_drv_obj->GetChannelOffers();
vmbus_drv_obj->GetChannelOffers();
+ wait_for_completion(&hv_channel_ready);
+
cleanup:
DPRINT_EXIT(VMBUS_DRV);
cleanup:
DPRINT_EXIT(VMBUS_DRV);