From: Vitaly Kuznetsov <[mailto:vkuzn...@redhat.com]>
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 <vkuzn...@redhat.com>
Signed-off-by: K. Y. Srinivasan <k...@microsoft.com>
---
drivers/hv/channel_mgmt.c | 1 -
1 files changed, 0 insertions(+), 1 deletions(-)
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index ba4b25f..36bacc7 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);
}
}
--
1.7.4.1
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