Messages in this thread | | | From | Cong Wang <> | Date | Thu, 9 Nov 2017 16:16:01 -0800 | Subject | Re: [vlan_device_event] BUG: unable to handle kernel paging request at 6b6b6ccf |
| |
On Thu, Nov 9, 2017 at 7:51 AM, Girish Moodalbail <girish.moodalbail@oracle.com> wrote: > > Upon receiving NETDEV_DOWN event, we are calling > > vlan_vid_del(dev, htons(ETH_P_8021Q), 0); > > which in turn calls call_rcu() to queue vlan_info_free_rcu() to be called at > some point. This free function frees the array[] > (vlan_info.vlan_grp.vn_devices_array). My guess is that > vlan_info_free_rcu() is being called first and then the array[] is being > accessed in vlan_device_event(). >
Well yes and no.
No, RCU itself is not broken and we clearly unpublish the RCU pointer before calling call_rcu().
Yes, I see where it is broken: the grp pointer still points to old dev->vlan_info, we should re-fetch it after vlan_vid_del().
I will send a fix.
Thanks!
| |