[dpdk-users] Kernel oops when adding vlan over kni driver

[Peter Fredriksson <pfredriksson@sandvine.com>]

Hi all,

I encounter a problem in my setup and am not able to find a nice solution or workaround. In our setup, we create VLANs on top of kni interfaces. They are created with another MAC address than the kni interface itself. This leads to a kernel oops due to the following.

* vlan_dev.c - vlan_dev_open
* since different mac - dev_uc_add
* dev_addr_list.c - dev_uc_add. Get lock with netif_addr_lock_bh and while holding the lock, __dev_set_rx_mode is used to set promiscuous mode if needed.
* dev.c - ops->ndo_set_rx_mode
* kni_net.c - kni_net_set_promiscusity
* kni_net.c - kni_net_process_request
* kni_net.c - kni_net_process_request calls wait_event_interruptible_timeout to wait for response from user space

And here I get the kernel Oops "BUG: scheduling while atomic" since wait_event_interruptible_timeout will trigger a call to schedule while we hold the lock from netif_addr_lock_bh.

I have created a temporary workaround where I have made kni_net_set_promiscusity just send the request and removed the response from user space since we anyway do not use it. Anyone else who has encountered this problem? Does anyone have a proposal for a better solution/workaround?


Best regards,

Peter

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