]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commit
udp: fix poll()
authorPaolo Abeni <pabeni@redhat.com>
Fri, 23 Jun 2017 12:19:51 +0000 (14:19 +0200)
committerDavid S. Miller <davem@davemloft.net>
Fri, 23 Jun 2017 15:18:43 +0000 (11:18 -0400)
commit9bd780f5e0663035d41a95a6b87eced011ba7e2a
tree9179096d14dd69ac1cd7355d55d0c4ade8ac0b9e
parent4b943faedfc29eda882851b772c06cecdf78d8e3
udp: fix poll()

Michael reported an UDP breakage caused by the commit b65ac44674dd
("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: b65ac44674dd ("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>
net/ipv4/udp.c