Messages in this thread | | | From | "Bill Bonaparte" <> | Subject | re: netfilter: nf_conntrack: there maybe a bug in __nf_conntrack_confirm, when it race against get_next_corpse | Date | Fri, 7 Nov 2014 14:47:32 +0800 |
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On Tue, 6 Nov 2014 21:01:00 "Jesper" <brouter@redhat.com> wrote: >There is several issues with your submission. I'll take care of resubmitting a patch in your name (so you will get credit in the git log). > >If you care to know, issues are: >1. you are not sending to the appropriate mailing lists, 2. patch is as an attachment (should be inlined), 3. the patch have style and white-space issues.
Thanks, Jesper. This is my first time to submit a patch, not know much about the rules. I will get it soon.
>> if there is a race at operating ct->status, there will be in >> alternative >> case: >> 1) IPS_DYING bit which set in get_next_corpse override other bits (e.g. >> IPS_SRC_NAT_DONE_BIT), or >> 2) other bits (e.g. IPS_SRC_NAT_DONE_BIT) which set in >> nf_nat_setup_info override IPS_DYING bit.
> Notice the set_bit() is atomic, so we don't have these issues (of bits getting overridden).
In most cases, we do the atomic operation on ct->status (with set_bit), but in function nf_nat_setup_info, we assume that unconfirmed ct is always holded by current cpu, and has no race against other cpus, so we don't use set_bit. the following code is extracted from the nf_nat_setup_info: /* Non-atomic: we own this at the moment. */ if (maniptype == NF_NAT_MANIP_SRC) ct->status |= IPS_SRC_NAT; else ct->status |= IPS_DST_NAT;
-- Best regards, Bill Bonaparte
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