Xiumei found a panic in esp offload:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
RIP: 0010:esp_output_done+0x101/0x160 [esp4]
Call Trace:
? esp_output+0x180/0x180 [esp4]
cryptd_aead_crypt+0x4c/0x90
cryptd_queue_worker+0x6e/0xa0
process_one_work+0x1a7/0x3b0
worker_thread+0x30/0x390
? create_worker+0x1a0/0x1a0
kthread+0x112/0x130
? kthread_flush_work_fn+0x10/0x10
ret_from_fork+0x35/0x40
It was caused by that skb secpath is used in esp_output_done() after it's
been released elsewhere.
The tx path for esp offload is:
__dev_queue_xmit()->
validate_xmit_skb_list()->
validate_xmit_xfrm()->
esp_xmit()->
esp_output_tail()->
aead_request_set_callback(esp_output_done) <--[1]
crypto_aead_encrypt() <--[2]
In [1], .callback is set, and in [2] it will trigger the worker schedule,
later on a kernel thread will call .callback(esp_output_done), as the call
trace shows.
But in validate_xmit_xfrm():
skb_list_walk_safe(skb, skb2, nskb) {
...
err = x->type_offload->xmit(x, skb2, esp_features); [esp_xmit]
...
}
When the err is -EINPROGRESS, which means this skb2 will be enqueued and
later gets encrypted and sent out by .callback later in a kernel thread,
skb2 should be removed fromt skb chain. Otherwise, it will get processed
again outside validate_xmit_xfrm(), which could release skb secpath, and
cause the panic above.
This patch is to remove the skb from the chain when it's enqueued in
cryptd_wq. While at it, remove the unnecessary 'if (!skb)' check.
Fixes: 3dca3f38cf ("xfrm: Separate ESP handling from segmentation for GRO packets.")
Reported-by: Xiumei Mu <xmu@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
d1d17a359c