Wolfgang,

On 12/12/2014 09:31 PM, Wolfgang Walter wrote:

There is one thing which indicates that there is also a problen in the GSO 
path, though. As my tests demonstrated disabling GSO on the physical interface 
serving the ipsec tunnel does not prevent the hangs. It does, though, if sk-

quoted

sk_gso_max_segs = 1 in sk_setup_caps() if sk_can_gso(sk) returns false. This 

was the first variation of the patch where sk->sk_gso_max_segs was not set if 
dst->header_len() is non zero.

if it's any help: Disabling TX checksumming prevents the hang
even on an unpatched 3.14.x kernel. You could check with your debug statements
in place the path of the packets with and without TX checksumming.

HTH,
Thomas