On Tue, Mar 22, 2016 at 06:29:48PM -0600, Subash Abhinov Kasiviswanathan wrote: > A crash is observed when a decrypted packet is processed in receive > path. get_rps_cpus() tries to dereference the skb->dev fields but it > appears that the device is freed from the poison pattern. > > [<ffffffc000af58ec>] get_rps_cpu+0x94/0x2f0 > [<ffffffc000af5f94>] netif_rx_internal+0x140/0x1cc > [<ffffffc000af6094>] netif_rx+0x74/0x94 > [<ffffffc000bc0b6c>] xfrm_input+0x754/0x7d0 > [<ffffffc000bc0bf8>] xfrm_input_resume+0x10/0x1c > [<ffffffc000ba6eb8>] esp_input_done+0x20/0x30 > [<ffffffc0000b64c8>] process_one_work+0x244/0x3fc > [<ffffffc0000b7324>] worker_thread+0x2f8/0x418 > [<ffffffc0000bb40c>] kthread+0xe0/0xec > > -013|get_rps_cpu( > | dev = 0xFFFFFFC08B688000, > | skb = 0xFFFFFFC0C76AAC00 -> ( > | dev = 0xFFFFFFC08B688000 -> ( > | name = > "...................................................... > | name_hlist = (next = 0xAAAAAAAAAAAAAAAA, pprev = > 0xAAAAAAAAAAA > > Following are the sequence of events observed - > > - Encrypted packet in receive path from netdevice is queued > - Encrypted packet queued for decryption (asynchronous) > - Netdevice brought down and freed > - Packet is decrypted and returned through callback in esp_input_done > - Packet is queued again for process in network stack using netif_rx > > Since the device appears to have been freed, the dereference of > skb->dev in get_rps_cpus() leads to an unhandled page fault > exception. > > Fix this by holding on to device reference when queueing packets > asynchronously and releasing the reference on call back return. > > v2: Make the change generic to xfrm as mentioned by Steffen and > update the title to xfrm > > Suggested-by: Herbert Xu <herb...@gondor.apana.org.au> > Signed-off-by: Jerome Stanislaus <jero...@codeaurora.org> > Signed-off-by: Subash Abhinov Kasiviswanathan <subas...@codeaurora.org>
Looks good. David, in case you want to take it directly into the net tree: Acked-by: Steffen Klassert <steffen.klass...@secunet.com>
