Messages in this thread | | | From | Matteo Croce <> | Date | Wed, 1 May 2019 11:27:12 +0200 | Subject | Re: [PATCH net] cls_matchall: avoid panic when receiving a packet before filter set |
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On Tue, Apr 30, 2019 at 11:25 PM Cong Wang <xiyou.wangcong@gmail.com> wrote: > > On Mon, Apr 29, 2019 at 10:38 AM Matteo Croce <mcroce@redhat.com> wrote: > > > > When a matchall classifier is added, there is a small time interval in > > which tp->root is NULL. If we receive a packet in this small time slice > > a NULL pointer dereference will happen, leading to a kernel panic: > > Hmm, why not just check tp->root against NULL in mall_classify()? > > Also, which is the offending commit here? Please add a Fixes: tag. > > Thanks.
Hi,
I just want to avoid an extra check which would be made for every packet. Probably the benefit over a check is negligible, but it's still a per-packet thing. If you prefer a simple check, I can make a v2 that way.
For the fixes tag, I didn't put it as I'm not really sure about the offending commit. I guess it's the following, what do you think?
commit ed76f5edccc98fa66f2337f0b3b255d6e1a568b7 Author: Vlad Buslov <vladbu@mellanox.com> Date: Mon Feb 11 10:55:38 2019 +0200
net: sched: protect filter_chain list with filter_chain_lock mutex
-- Matteo Croce per aspera ad upstream
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