Commit 09a19628 authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Greg Kroah-Hartman

Drivers: hv: vmbus: teardown hv_vmbus_con workqueue and vmbus_connection pages on shutdown

We need to destroy hv_vmbus_con on module shutdown, otherwise the following
crash is sometimes observed:

[   76.569845] hv_vmbus: Hyper-V Host Build:9600-6.3-17-0.17039; Vmbus version:3.0
[   82.598859] BUG: unable to handle kernel paging request at ffffffffa0003480
[   82.599287] IP: [<ffffffffa0003480>] 0xffffffffa0003480
[   82.599287] PGD 1f34067 PUD 1f35063 PMD 3f72d067 PTE 0
[   82.599287] Oops: 0010 [#1] SMP
[   82.599287] Modules linked in: [last unloaded: hv_vmbus]
[   82.599287] CPU: 0 PID: 26 Comm: kworker/0:1 Not tainted 3.19.0-rc5_bug923184+ #488
[   82.599287] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v1.0 11/26/2012
[   82.599287] Workqueue: hv_vmbus_con 0xffffffffa0003480
[   82.599287] task: ffff88007b6ddfa0 ti: ffff88007f8f8000 task.ti: ffff88007f8f8000
[   82.599287] RIP: 0010:[<ffffffffa0003480>]  [<ffffffffa0003480>] 0xffffffffa0003480
[   82.599287] RSP: 0018:ffff88007f8fbe00  EFLAGS: 00010202
...

To avoid memory leaks we need to free monitor_pages and int_page for
vmbus_connection. Implement vmbus_disconnect() function by separating cleanup
path from vmbus_connect().

As we use hv_vmbus_con to release channels (see free_channel() in channel_mgmt.c)
we need to make sure the work was done before we remove the queue, do that with
drain_workqueue(). We also need to avoid handling messages  which can (potentially)
create new channels, so set vmbus_connection.conn_state = DISCONNECTED at the very
beginning of vmbus_exit() and check for that in vmbus_onmessage_work().
Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent adcde069
......@@ -216,10 +216,21 @@ int vmbus_connect(void)
cleanup:
pr_err("Unable to connect to host\n");
vmbus_connection.conn_state = DISCONNECTED;
vmbus_disconnect();
kfree(msginfo);
return ret;
}
if (vmbus_connection.work_queue)
void vmbus_disconnect(void)
{
if (vmbus_connection.work_queue) {
drain_workqueue(vmbus_connection.work_queue);
destroy_workqueue(vmbus_connection.work_queue);
}
if (vmbus_connection.int_page) {
free_pages((unsigned long)vmbus_connection.int_page, 0);
......@@ -230,10 +241,6 @@ int vmbus_connect(void)
free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
vmbus_connection.monitor_pages[0] = NULL;
vmbus_connection.monitor_pages[1] = NULL;
kfree(msginfo);
return ret;
}
/*
......
......@@ -692,6 +692,7 @@ void vmbus_free_channels(void);
/* Connection interface */
int vmbus_connect(void);
void vmbus_disconnect(void);
int vmbus_post_msg(void *buffer, size_t buflen);
......
......@@ -574,6 +574,10 @@ static void vmbus_onmessage_work(struct work_struct *work)
{
struct onmessage_work_context *ctx;
/* Do not process messages if we're in DISCONNECTED state */
if (vmbus_connection.conn_state == DISCONNECTED)
return;
ctx = container_of(work, struct onmessage_work_context,
work);
vmbus_onmessage(&ctx->msg);
......@@ -1025,12 +1029,14 @@ static int __init hv_acpi_init(void)
static void __exit vmbus_exit(void)
{
vmbus_connection.conn_state = DISCONNECTED;
hv_remove_vmbus_irq();
vmbus_free_channels();
bus_unregister(&hv_bus);
hv_cleanup();
acpi_bus_unregister_driver(&vmbus_acpi_driver);
hv_cpu_hotplug_quirk(false);
vmbus_disconnect();
}
......
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