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Commit 2115b561 authored by K. Y. Srinivasan's avatar K. Y. Srinivasan Committed by Greg Kroah-Hartman
Browse files

Drivers: hv: vmbus: Properly protect calls to smp_processor_id() 



Disable preemption when sampling current processor ID when preemption
is otherwise possible.

Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Tested-by: default avatarSitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b29ef354

drivers/hv/channel.c

+5 −2
Original line number Diff line number Diff line
@@ -486,11 +486,14 @@ static int vmbus_close_internal(struct vmbus_channel *channel) 
	channel->state = CHANNEL_OPEN_STATE;

	channel->sc_creation_callback = NULL;

	/* Stop callback and cancel the timer asap */

	if (channel->target_cpu != smp_processor_id())

	if (channel->target_cpu != get_cpu()) {

		put_cpu();

		smp_call_function_single(channel->target_cpu, reset_channel_cb,

					 channel, true);

	else

	} else {

		reset_channel_cb(channel);

		put_cpu();

	}



	/* Send a closing message */

drivers/hv/channel_mgmt.c

+15 −6
Original line number Diff line number Diff line
@@ -224,11 +224,14 @@ static void vmbus_process_rescind_offer(struct work_struct *work) 
	msg.header.msgtype = CHANNELMSG_RELID_RELEASED;

	vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released));



	if (channel->target_cpu != smp_processor_id())

	if (channel->target_cpu != get_cpu()) {

		put_cpu();

		smp_call_function_single(channel->target_cpu,

					 percpu_channel_deq, channel, true);

	else

	} else {

		percpu_channel_deq(channel);

		put_cpu();

	}



	if (channel->primary_channel == NULL) {

		spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
@@ -294,12 +297,15 @@ static void vmbus_process_offer(struct work_struct *work) 
	spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);



	if (enq) {

		if (newchannel->target_cpu != smp_processor_id())

		if (newchannel->target_cpu != get_cpu()) {

			put_cpu();

			smp_call_function_single(newchannel->target_cpu,

						 percpu_channel_enq,

						 newchannel, true);

		else

		} else {

			percpu_channel_enq(newchannel);

			put_cpu();

		}

	}

	if (!fnew) {

		/*
@@ -314,12 +320,15 @@ static void vmbus_process_offer(struct work_struct *work) 
			list_add_tail(&newchannel->sc_list, &channel->sc_list);

			spin_unlock_irqrestore(&channel->sc_lock, flags);



			if (newchannel->target_cpu != smp_processor_id())

			if (newchannel->target_cpu != get_cpu()) {

				put_cpu();

				smp_call_function_single(newchannel->target_cpu,

							 percpu_channel_enq,

							 newchannel, true);

			else

			} else {

				percpu_channel_enq(newchannel);

				put_cpu();

			}



			newchannel->state = CHANNEL_OPEN_STATE;

			if (channel->sc_creation_callback != NULL)