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:[<ffffffff811d2e1b>] [<ffffffff811d2e1b>] __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 <vkuznets@xxxxxxxxxx>
---
drivers/hv/channel_mgmt.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 877a944..0141a3d 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -259,7 +259,6 @@ 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);
}
}
--
1.9.3
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