l2tp: avoid skb truesize bug if headroom is increased
authorJames Chapman <jchapman@katalix.com>
Mon, 19 May 2008 21:10:01 +0000 (14:10 -0700)
committerDavid S. Miller <davem@davemloft.net>
Mon, 19 May 2008 21:10:01 +0000 (14:10 -0700)
commit090c48d3dd5ea90b37350334aaed9a93b0c1e0a1
treeb912bf1bd1519bfcccd36e0927a7adf43f34587b
parent066b2118976e6e7cc50eed39e2747c75343a23c4
l2tp: avoid skb truesize bug if headroom is increased

A user reported seeing occasional bugs such as the following when
using the L2TP driver.

  SKB BUG: Invalid truesize (272) len=72, sizeof(sk_buff)=208

When L2TP adds its header in the transmit path, it might need to
increase the headroom of the skb. In some cases, the increased
headroom trips a kernel bug when the skb is freed because the skb has
grown beyond its truesize value. The fix is to increase the truesize
by the amount of headroom added, after orphaning the skb.

While here, fix a misleading comment.

Thanks to Iouri Kharon <bc-info@styx.cabel.net> for the initial
report and testing the fix.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/pppol2tp.c