| Message ID | 20201101191620.589272-1-vladimir.oltean@nxp.com |
|---|---|
| Headers | show |
| Series | Generic TX reallocation for DSA | expand |
On Sun, 1 Nov 2020 21:16:08 +0200 Vladimir Oltean wrote: > Christian has reported buggy usage of skb_put() in tag_ksz.c, which is > only triggerable in real life using his not-yet-published patches for > IEEE 1588 timestamping on Micrel KSZ switches. > > The concrete problem there is that the driver can end up calling > skb_put() and exceed the end of the skb data area, because even though > it had reallocated the frame once before, it hadn't reallocated it large > enough. Christian explained it in more detail here: > > https://lore.kernel.org/netdev/20201014161719.30289-1-ceggers@arri.de/ > https://lore.kernel.org/netdev/20201016200226.23994-1-ceggers@arri.de/ > > But actually there's a bigger problem, which is that some taggers which > get more rarely tested tend to do some shenanigans which are uncaught > for the longest time, and in the meanwhile, their code gets copy-pasted > into other taggers, creating a mess. For example, the tail tagging > driver for Marvell 88E6060 currently reallocates _every_single_frame_ on > TX. Is that an obvious indication that nobody is using it? Sure. Is it a > good model to follow when developing a new tail tagging driver? No. > > DSA has all the information it needs in order to simplify the job of a > tagger on TX. It knows whether it's a normal or a tail tagger, and what > is the protocol overhead it incurs. So this series performs the > reallocation centrally. Applied, thank you!
Christian has reported buggy usage of skb_put() in tag_ksz.c, which is only triggerable in real life using his not-yet-published patches for IEEE 1588 timestamping on Micrel KSZ switches. The concrete problem there is that the driver can end up calling skb_put() and exceed the end of the skb data area, because even though it had reallocated the frame once before, it hadn't reallocated it large enough. Christian explained it in more detail here: https://lore.kernel.org/netdev/20201014161719.30289-1-ceggers@arri.de/ https://lore.kernel.org/netdev/20201016200226.23994-1-ceggers@arri.de/ But actually there's a bigger problem, which is that some taggers which get more rarely tested tend to do some shenanigans which are uncaught for the longest time, and in the meanwhile, their code gets copy-pasted into other taggers, creating a mess. For example, the tail tagging driver for Marvell 88E6060 currently reallocates _every_single_frame_ on TX. Is that an obvious indication that nobody is using it? Sure. Is it a good model to follow when developing a new tail tagging driver? No. DSA has all the information it needs in order to simplify the job of a tagger on TX. It knows whether it's a normal or a tail tagger, and what is the protocol overhead it incurs. So this series performs the reallocation centrally. Changes in v3: - Use dev_kfree_skb_any due to potential hardirq context in xmit path. Changes in v2: - Dropped the tx_realloc counters for now, since the patch was pretty controversial and I lack the time at the moment to introduce new UAPI for that. - Do padding for tail taggers irrespective of whether they need to reallocate the skb or not. Christian Eggers (2): net: dsa: tag_ksz: don't allocate additional memory for padding/tagging net: dsa: trailer: don't allocate additional memory for padding/tagging Vladimir Oltean (10): net: dsa: implement a central TX reallocation procedure net: dsa: tag_qca: let DSA core deal with TX reallocation net: dsa: tag_ocelot: let DSA core deal with TX reallocation net: dsa: tag_mtk: let DSA core deal with TX reallocation net: dsa: tag_lan9303: let DSA core deal with TX reallocation net: dsa: tag_edsa: let DSA core deal with TX reallocation net: dsa: tag_brcm: let DSA core deal with TX reallocation net: dsa: tag_dsa: let DSA core deal with TX reallocation net: dsa: tag_gswip: let DSA core deal with TX reallocation net: dsa: tag_ar9331: let DSA core deal with TX reallocation net/dsa/slave.c | 45 ++++++++++++++++++++++++++ net/dsa/tag_ar9331.c | 3 -- net/dsa/tag_brcm.c | 3 -- net/dsa/tag_dsa.c | 5 --- net/dsa/tag_edsa.c | 4 --- net/dsa/tag_gswip.c | 5 --- net/dsa/tag_ksz.c | 73 ++++++------------------------------------- net/dsa/tag_lan9303.c | 9 ------ net/dsa/tag_mtk.c | 3 -- net/dsa/tag_ocelot.c | 7 ----- net/dsa/tag_qca.c | 3 -- net/dsa/tag_trailer.c | 31 ++---------------- 12 files changed, 56 insertions(+), 135 deletions(-)