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  1. 28 7月, 2020 4 次提交
  3. 27 7月, 2020 3 次提交
  5. 25 7月, 2020 2 次提交
    • X
      drivers/net/wan: lapb: Corrected the usage of skb_cow · 8754e137
      由 Xie He 提交于 
      This patch fixed 2 issues with the usage of skb_cow in LAPB drivers
"lapbether" and "hdlc_x25":

1) After skb_cow fails, kfree_skb should be called to drop a reference
to the skb. But in both drivers, kfree_skb is not called.

2) skb_cow should be called before skb_push so that is can ensure the
safety of skb_push. But in "lapbether", it is incorrectly called after
skb_push.

More details about these 2 issues:

1) The behavior of calling kfree_skb on failure is also the behavior of
netif_rx, which is called by this function with "return netif_rx(skb);".
So this function should follow this behavior, too.

2) In "lapbether", skb_cow is called after skb_push. This results in 2
logical issues:
   a) skb_push is not protected by skb_cow;
   b) An extra headroom of 1 byte is ensured after skb_push. This extra
      headroom has no use in this function. It also has no use in the
      upper-layer function that this function passes the skb to
      (x25_lapb_receive_frame in net/x25/x25_dev.c).
So logically skb_cow should instead be called before skb_push.

Cc: Eric Dumazet <edumazet@google.com>
Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: NXie He <xie.he.0141@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      8754e137
    • A
      xen-netfront: fix potential deadlock in xennet_remove() · c2c63310
      由 Andrea Righi 提交于 
      There's a potential race in xennet_remove(); this is what the driver is
doing upon unregistering a network device:

  1. state = read bus state
  2. if state is not "Closed":
  3.    request to set state to "Closing"
  4.    wait for state to be set to "Closing"
  5.    request to set state to "Closed"
  6.    wait for state to be set to "Closed"

If the state changes to "Closed" immediately after step 1 we are stuck
forever in step 4, because the state will never go back from "Closed" to
"Closing".

Make sure to check also for state == "Closed" in step 4 to prevent the
deadlock.

Also add a 5 sec timeout any time we wait for the bus state to change,
to avoid getting stuck forever in wait_event().
Signed-off-by: NAndrea Righi <andrea.righi@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      c2c63310
  7. 24 7月, 2020 31 次提交