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由 subashab@codeaurora.org 提交于
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: NHerbert Xu <herbert@gondor.apana.org.au> Signed-off-by: NJerome Stanislaus <jeromes@codeaurora.org> Signed-off-by: NSubash Abhinov Kasiviswanathan <subashab@codeaurora.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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