From: Vitaly Kuznetsov <[mailto:vkuznets@xxxxxxxxxx]> 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: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> --- drivers/hv/connection.c | 17 ++++++++++++----- drivers/hv/hyperv_vmbus.h | 1 + drivers/hv/vmbus_drv.c | 6 ++++++ 3 files changed, 19 insertions(+), 5 deletions(-) diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c index a63a795..c4acd1c 100644 --- a/drivers/hv/connection.c +++ b/drivers/hv/connection.c @@ -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 @@ cleanup: 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; } /* diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h index 44b1c94..6cf2de9 100644 --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -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); diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 1fb8db0..f824c08 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -571,6 +571,10 @@ 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); @@ -1095,12 +1099,14 @@ cleanup: 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(); } -- 1.7.4.1 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
