This is a note to let you know that I've just added the patch titled
Drivers: hv: vmbus: Fix a rescind issue
to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: drivers-hv-vmbus-fix-a-rescind-issue.patch and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 7fa32e5ec28b1609abc0b797b58267f725fc3964 Mon Sep 17 00:00:00 2001
From: "K. Y. Srinivasan" kys@microsoft.com Date: Tue, 14 Nov 2017 06:53:33 -0700 Subject: Drivers: hv: vmbus: Fix a rescind issue
From: K. Y. Srinivasan kys@microsoft.com
commit 7fa32e5ec28b1609abc0b797b58267f725fc3964 upstream.
The current rescind processing code will not correctly handle the case where the host immediately rescinds a channel that has been offerred. In this case, we could be blocked in the open call and since the channel is rescinded, the host will not respond and we could be blocked forever in the vmbus open call.i Fix this problem.
Signed-off-by: K. Y. Srinivasan kys@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/hv/channel.c | 10 ++++++++-- drivers/hv/channel_mgmt.c | 7 ++++--- include/linux/hyperv.h | 1 + 3 files changed, 13 insertions(+), 5 deletions(-)
--- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -640,22 +640,28 @@ void vmbus_close(struct vmbus_channel *c */ return; } - mutex_lock(&vmbus_connection.channel_mutex); /* * Close all the sub-channels first and then close the * primary channel. */ list_for_each_safe(cur, tmp, &channel->sc_list) { cur_channel = list_entry(cur, struct vmbus_channel, sc_list); - vmbus_close_internal(cur_channel); if (cur_channel->rescind) { + wait_for_completion(&cur_channel->rescind_event); + mutex_lock(&vmbus_connection.channel_mutex); + vmbus_close_internal(cur_channel); hv_process_channel_removal( cur_channel->offermsg.child_relid); + } else { + mutex_lock(&vmbus_connection.channel_mutex); + vmbus_close_internal(cur_channel); } + mutex_unlock(&vmbus_connection.channel_mutex); } /* * Now close the primary. */ + mutex_lock(&vmbus_connection.channel_mutex); vmbus_close_internal(channel); mutex_unlock(&vmbus_connection.channel_mutex); } --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -333,6 +333,7 @@ static struct vmbus_channel *alloc_chann return NULL;
spin_lock_init(&channel->lock); + init_completion(&channel->rescind_event);
INIT_LIST_HEAD(&channel->sc_list); INIT_LIST_HEAD(&channel->percpu_list); @@ -883,6 +884,7 @@ static void vmbus_onoffer_rescind(struct /* * Now wait for offer handling to complete. */ + vmbus_rescind_cleanup(channel); while (READ_ONCE(channel->probe_done) == false) { /* * We wait here until any channel offer is currently @@ -898,7 +900,6 @@ static void vmbus_onoffer_rescind(struct if (channel->device_obj) { if (channel->chn_rescind_callback) { channel->chn_rescind_callback(channel); - vmbus_rescind_cleanup(channel); return; } /* @@ -907,7 +908,6 @@ static void vmbus_onoffer_rescind(struct */ dev = get_device(&channel->device_obj->device); if (dev) { - vmbus_rescind_cleanup(channel); vmbus_device_unregister(channel->device_obj); put_device(dev); } @@ -921,13 +921,14 @@ static void vmbus_onoffer_rescind(struct * 2. Then close the primary channel. */ mutex_lock(&vmbus_connection.channel_mutex); - vmbus_rescind_cleanup(channel); if (channel->state == CHANNEL_OPEN_STATE) { /* * The channel is currently not open; * it is safe for us to cleanup the channel. */ hv_process_channel_removal(rescind->child_relid); + } else { + complete(&channel->rescind_event); } mutex_unlock(&vmbus_connection.channel_mutex); } --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -708,6 +708,7 @@ struct vmbus_channel { u8 monitor_bit;
bool rescind; /* got rescind msg */ + struct completion rescind_event;
u32 ringbuffer_gpadlhandle;
Patches currently in stable-queue which might be from kys@microsoft.com are
queue-4.14/hv-kvp-avoid-reading-past-allocated-blocks-from-kvp-file.patch queue-4.14/drivers-hv-vmbus-fix-a-rescind-issue.patch