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  1. 30 8月, 2005 25 次提交
  3. 24 8月, 2005 6 次提交
  5. 21 8月, 2005 3 次提交
  7. 19 8月, 2005 2 次提交
  9. 18 8月, 2005 1 次提交
    • H
      [TCP]: Fix bug #5070: kernel BUG at net/ipv4/tcp_output.c:864 · 35d59efd
      由 Herbert Xu 提交于 
      1) We send out a normal sized packet with TSO on to start off.
2) ICMP is received indicating a smaller MTU.
3) We send the current sk_send_head which needs to be fragmented
since it was created before the ICMP event.  The first fragment
is then sent out.

At this point the remaining fragment is allocated by tcp_fragment.
However, its size is padded to fit the L1 cache-line size therefore
creating tail-room up to 124 bytes long.

This fragment will also be sitting at sk_send_head.

4) tcp_sendmsg is called again and it stores data in the tail-room of
of the fragment.
5) tcp_push_one is called by tcp_sendmsg which then calls tso_fragment
since the packet as a whole exceeds the MTU.

At this point we have a packet that has data in the head area being
fed to tso_fragment which bombs out.

My take on this is that we shouldn't ever call tcp_fragment on a TSO
socket for a packet that is yet to be transmitted since this creates
a packet on sk_send_head that cannot be extended.

So here is a patch to change it so that tso_fragment is always used
in this case.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      35d59efd
  11. 17 8月, 2005 1 次提交
    • H
      [TCP]: Fix bug #5070: kernel BUG at net/ipv4/tcp_output.c:864 · c8ac3774
      由 Herbert Xu 提交于 
      1) We send out a normal sized packet with TSO on to start off.
2) ICMP is received indicating a smaller MTU.
3) We send the current sk_send_head which needs to be fragmented
since it was created before the ICMP event.  The first fragment
is then sent out.

At this point the remaining fragment is allocated by tcp_fragment.
However, its size is padded to fit the L1 cache-line size therefore
creating tail-room up to 124 bytes long.

This fragment will also be sitting at sk_send_head.

4) tcp_sendmsg is called again and it stores data in the tail-room of
of the fragment.
5) tcp_push_one is called by tcp_sendmsg which then calls tso_fragment
since the packet as a whole exceeds the MTU.

At this point we have a packet that has data in the head area being
fed to tso_fragment which bombs out.

My take on this is that we shouldn't ever call tcp_fragment on a TSO
socket for a packet that is yet to be transmitted since this creates
a packet on sk_send_head that cannot be extended.

So here is a patch to change it so that tso_fragment is always used
in this case.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      c8ac3774
  13. 11 8月, 2005 1 次提交
    • H
      [TCP]: Adjust {p,f}ackets_out correctly in tcp_retransmit_skb() · b5da623a
      由 Herbert Xu 提交于 
      Well I've only found one potential cause for the assertion
failure in tcp_mark_head_lost.  First of all, this can only
occur if cnt > 1 since tp->packets_out is never zero here.
If it did hit zero we'd have much bigger problems.

So cnt is equal to fackets_out - reordering.  Normally
fackets_out is less than packets_out.  The only reason
I've found that might cause fackets_out to exceed packets_out
is if tcp_fragment is called from tcp_retransmit_skb with a
TSO skb and the current MSS is greater than the MSS stored
in the TSO skb.  This might occur as the result of an expiring
dst entry.

In that case, packets_out may decrease (line 1380-1381 in
tcp_output.c).  However, fackets_out is unchanged which means
that it may in fact exceed packets_out.

Previously tcp_retrans_try_collapse was the only place where
packets_out can go down and it takes care of this by decrementing
fackets_out.

So we should make sure that fackets_out is reduced by an appropriate
amount here as well.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      b5da623a
  15. 09 8月, 2005 1 次提交