l2tp: dont play with skb->truesize
Andrew Savchenko reported a DNS failure and we diagnosed that some UDP sockets were unable to send more packets because their sk_wmem_alloc was corrupted after a while (tx_queue column in following trace) $ cat /proc/net/udp sl local_address rem_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode ref pointer drops ... 459: 00000000:0270 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4507 2 ffff88003d612380 0 466: 00000000:0277 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4802 2 ffff88003d613180 0 470: 076A070A:007B 00000000:0000 07 FFFF4600:00000000 00:00000000 00000000 123 0 5552 2 ffff880039974380 0 470: 010213AC:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4986 2 ffff88003dbd3180 0 470: 010013AC:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4985 2 ffff88003dbd2e00 0 470: 00FCA8C0:007B 00000000:0000 07 FFFFFB00:00000000 00:00000000 00000000 0 0 4984 2 ffff88003dbd2a80 0 ... Playing with skb->truesize is tricky, especially when skb is attached to a socket, as we can fool memory charging. Just remove this code, its not worth trying to be ultra precise in xmit path. Reported-by:Andrew Savchenko <bircoph@gmail.com> Tested-by:
Andrew Savchenko <bircoph@gmail.com> Signed-off-by:
Eric Dumazet <edumazet@google.com> Cc: James Chapman <jchapman@katalix.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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