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Paolo Abeni authored
Michael reported an UDP breakage caused by the commit b65ac446 ("udp: try to avoid 2 cache miss on dequeue"). The function __first_packet_length() can update the checksum bits of the pending skb, making the scratched area out-of-sync, and setting skb->csum, if the skb was previously in need of checksum validation. On later recvmsg() for such skb, checksum validation will be invoked again - due to the wrong udp_skb_csum_unnecessary() value - and will fail, causing the valid skb to be dropped. This change addresses the issue refreshing the scratch area in __first_packet_length() after the possible checksum update. Fixes: b65ac446 ("udp: try to avoid 2 cache miss on dequeue") Reported-by:
Michael Ellerman <mpe@ellerman.id.au> Signed-off-by:
Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by:
Paolo Abeni <pabeni@redhat.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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