From 096c605feb3d85b309e95db2afc01584b967cc23 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Wed, 22 Apr 2015 21:31:29 -0700 Subject: [PATCH] Drivers: hv: vmbus: unregister panic notifier on module unload Commit 96c1d0581d00f7abe033350edb021a9d947d8d81 ("Drivers: hv: vmbus: Add support for VMBus panic notifier handler") introduced atomic_notifier_chain_register() call on module load. We also need to call atomic_notifier_chain_unregister() on module unload as otherwise the following crash is observed when we bring hv_vmbus back: [ 39.788877] BUG: unable to handle kernel paging request at ffffffffa00078a8 [ 39.788877] IP: [] notifier_call_chain+0x3f/0x80 ... [ 39.788877] Call Trace: [ 39.788877] [] __atomic_notifier_call_chain+0x5d/0x90 ... [ 39.788877] [] ? atomic_notifier_chain_register+0x38/0x70 [ 39.788877] [] ? atomic_notifier_chain_register+0x17/0x70 [ 39.788877] [] hv_acpi_init+0x14f/0x1000 [hv_vmbus] [ 39.788877] [] do_one_initcall+0xd4/0x210 Signed-off-by: Vitaly Kuznetsov Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- drivers/hv/vmbus_drv.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 0d8d1d79408c..7870a906365e 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -1108,6 +1108,10 @@ static void __exit vmbus_exit(void) hv_synic_clockevents_cleanup(); hv_remove_vmbus_irq(); vmbus_free_channels(); + if (ms_hyperv.features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { + atomic_notifier_chain_unregister(&panic_notifier_list, + &hyperv_panic_block); + } bus_unregister(&hv_bus); hv_cleanup(); for_each_online_cpu(cpu) -- 2.20.1