https://github.com/torvalds/linux
Revision 5861c8cb1c90fc171d56994827a66a5595a44d56 authored by Jakub Kicinski on 12 November 2020, 17:55:58 UTC, committed by Jakub Kicinski on 12 November 2020, 17:55:59 UTC
Alexander Lobakin says: ==================== net: udp: fix Fast/frag0 UDP GRO While testing UDP GSO fraglists forwarding through driver that uses Fast GRO (via napi_gro_frags()), I was observing lots of out-of-order iperf packets: [ ID] Interval Transfer Bitrate Jitter [SUM] 0.0-40.0 sec 12106 datagrams received out-of-order Simple switch to napi_gro_receive() or any other method without frag0 shortcut completely resolved them. I've found two incorrect header accesses in GRO receive callback(s): - udp_hdr() (instead of udp_gro_udphdr()) that always points to junk in "fast" mode and could probably do this in "regular". This was the actual bug that caused all out-of-order delivers; - udp{4,6}_lib_lookup_skb() -> ip{,v6}_hdr() (instead of skb_gro_network_header()) that potentionally might return odd pointers in both modes. Each patch addresses one of these two issues. This doesn't cover a support for nested tunnels as it's out of the subject and requires more invasive changes. It will be handled separately in net-next series. Credits: Cc: Eric Dumazet <edumazet@google.com> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Willem de Bruijn <willemb@google.com> Since v4 [0]: - split the fix into two logical ones (Willem); - replace ternaries with plain ifs to beautify the code (Jakub); - drop p->data part to reintroduce it later in abovementioned set. Since v3 [1]: - restore the original {,__}udp{4,6}_lib_lookup_skb() and use private versions of them inside GRO code (Willem). Since v2 [2]: - dropped redundant check introduced in v2 as it's performed right before (thanks to Eric); - udp_hdr() switched to data + off for skbs from list (also Eric); - fixed possible malfunction of {,__}udp{4,6}_lib_lookup_skb() with Fast/frag0 due to ip{,v6}_hdr() usage (Willem). Since v1 [3]: - added a NULL pointer check for "uh" as suggested by Willem. [0] https://lore.kernel.org/netdev/Ha2hou5eJPcblo4abjAqxZRzIl1RaLs2Hy0oOAgFs@cp4-web-036.plabs.ch [1] https://lore.kernel.org/netdev/MgZce9htmEtCtHg7pmWxXXfdhmQ6AHrnltXC41zOoo@cp7-web-042.plabs.ch [2] https://lore.kernel.org/netdev/0eaG8xtbtKY1dEKCTKUBubGiC9QawGgB3tVZtNqVdY@cp4-web-030.plabs.ch [3] https://lore.kernel.org/netdev/YazU6GEzBdpyZMDMwJirxDX7B4sualpDG68ADZYvJI@cp4-web-034.plabs.ch ==================== Link: https://lore.kernel.org/r/hjGOh0iCOYyo1FPiZh6TMXcx3YCgNs1T1eGKLrDz8@cp4-web-037.plabs.ch Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Tip revision: 5861c8cb1c90fc171d56994827a66a5595a44d56 authored by Jakub Kicinski on 12 November 2020, 17:55:58 UTC
Merge branch 'net-udp-fix-fast-frag0-udp-gro'
Merge branch 'net-udp-fix-fast-frag0-udp-gro'
Tip revision: 5861c8c
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