From: Vitaly Kuznetsov Date: Fri, 27 Feb 2015 19:25:53 +0000 (-0800) Subject: Drivers: hv: vmbus: avoid double kfree for device_obj X-Git-Tag: firefly_0821_release~176^2~1906^2~123 X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=adcde069a85cb6674bdcf5f49f434d18b2db6e58;p=firefly-linux-kernel-4.4.55.git Drivers: hv: vmbus: avoid double kfree for device_obj On driver shutdown device_obj is being freed twice: 1) In vmbus_free_channels() 2) vmbus_device_release() (which is being triggered by device_unregister() in vmbus_device_unregister(). This double kfree leads to the following sporadic crash on driver unload: [ 23.469876] general protection fault: 0000 [#1] SMP [ 23.470036] Modules linked in: hv_vmbus(-) [ 23.470036] CPU: 2 PID: 213 Comm: rmmod Not tainted 3.19.0-rc5_bug923184+ #488 [ 23.470036] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090006 05/23/2012 [ 23.470036] task: ffff880036ef1cb0 ti: ffff880036ce8000 task.ti: ffff880036ce8000 [ 23.470036] RIP: 0010:[] [] __kmalloc_node_track_caller+0xdb/0x1e0 [ 23.470036] RSP: 0018:ffff880036cebcc8 EFLAGS: 00010246 ... When this crash does not happen on driver unload the similar one is expected if we try to load hv_vmbus again. Remove kfree from vmbus_free_channels() as freeing it from vmbus_device_release() seems right. Signed-off-by: Vitaly Kuznetsov Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index ba4b25f0b213..36bacc75a32a 100644 --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -262,7 +262,6 @@ void vmbus_free_channels(void) list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { vmbus_device_unregister(channel->device_obj); - kfree(channel->device_obj); free_channel(channel); } }