Neale, Could this be hitting the same /32 issue I'm in the process of fixing with https://gerrit.fd.io/r/c/vpp/+/33495 ? If the interface has an IPv6 /32 assigned... it would be IPv6 enabled, but fib_sas would fail to get its source address, ND would fail, and we'd hit the SEGV we are seeing on copy... is that possibly the root cause?
Ed On Fri, Aug 20, 2021 at 10:05 AM Ed Warnicke <hagb...@gmail.com> wrote: > Got it. That makes sense :) > > Ed > > On Fri, Aug 20, 2021 at 9:58 AM Neale Ranns <ne...@graphiant.com> wrote: > >> Hi Ed, >> >> >> >> When creating an adjacency for the first time we send out a probe packet >> (ARP/ND) to see if the peer will resolve it. >> >> >> >> /neale >> >> >> >> *From: *Ed Warnicke <hagb...@gmail.com> >> *Date: *Friday, 20 August 2021 at 16:54 >> *To: *Neale Ranns <ne...@graphiant.com> >> *Cc: *zsta...@gmail.com <zsta...@gmail.com>, Artem Glazychev < >> artem.glazyc...@xored.com>, vpp-dev <vpp-dev@lists.fd.io> >> *Subject: *Re: [vpp-dev] Adding new route via ipv6 link-local >> >> Neale, >> >> >> >> Question... looking at the trace it looks like we are having an issue >> with fib_sas6_get ... could you help me understand why we are calling >> fib_sas6_get in this situation? >> >> >> >> Ed >> >> >> >> On Fri, Aug 20, 2021 at 9:49 AM Neale Ranns <ne...@graphiant.com> wrote: >> >> >> >> Hi Ed, >> >> >> >> It does. But in this case the command is adding a route through an >> interface, which is not the same as configuring a prefix on an interface >> (nor ip6 enabling it). >> >> >> >> /neale >> >> >> >> *From: *Ed Warnicke <hagb...@gmail.com> >> *Date: *Friday, 20 August 2021 at 16:40 >> *To: *Neale Ranns <ne...@graphiant.com> >> *Cc: *zsta...@gmail.com <zsta...@gmail.com>, Artem Glazychev < >> artem.glazyc...@xored.com>, vpp-dev <vpp-dev@lists.fd.io> >> *Subject: *Re: [vpp-dev] Adding new route via ipv6 link-local >> >> Neale, >> >> >> >> I'm a bit confused... I had previously thought that *adding* an IPv6 >> address to a link *did* IPv6 enable it... >> >> >> >> Ed >> >> >> >> On Fri, Aug 20, 2021 at 9:20 AM Neale Ranns <ne...@graphiant.com> wrote: >> >> Hi Artem, Stanislav, >> >> >> >> I agree graceful handling is needed, return false if there is no link >> local. >> >> >> >> If you enabled ip6 on the link first, this wouldn’t be a problem. The >> link will need to be ip6 enabled if you want something to reply. >> >> >> >> /neale >> >> >> >> >> >> *From: *vpp-dev@lists.fd.io <vpp-dev@lists.fd.io> on behalf of Stanislav >> Zaikin via lists.fd.io <zstaseg=gmail....@lists.fd.io> >> *Date: *Friday, 20 August 2021 at 16:10 >> *To: *Artem Glazychev <artem.glazyc...@xored.com> >> *Cc: *vpp-dev <vpp-dev@lists.fd.io> >> *Subject: *Re: [vpp-dev] Adding new route via ipv6 link-local >> >> Hello Artem, >> >> >> >> Looks like we need (at least) to add a check for nullptr. >> >> >> >> DBGvpp# create tap >> tap0 >> DBGvpp# set interface state tap0 up >> DBGvpp# ip route add fa::1/120 via fe80::1 tap0 >> >> Thread 1 "vpp_main" received signal SIGSEGV, Segmentation fault. >> 0x00007ffff774ba90 in ip6_address_copy (dst=0x7fffaf487aa0, src=0x0) at >> /home/zstas/vpp/src/vnet/ip/ip6_packet.h:129 >> 129 dst->as_u64[0] = src->as_u64[0]; >> (gdb) bt >> #0 0x00007ffff774ba90 in ip6_address_copy (dst=0x7fffaf487aa0, src=0x0) >> at /home/zstas/vpp/src/vnet/ip/ip6_packet.h:129 >> #1 0x00007ffff774b892 in fib_sas6_get (sw_if_index=1, >> dst=0x7fffb91b4e50, src=0x7fffaf487aa0) at >> /home/zstas/vpp/src/vnet/fib/fib_sas.c:105 >> >> >> >> On Fri, 20 Aug 2021 at 15:20, Artem Glazychev <artem.glazyc...@xored.com> >> wrote: >> >> Hello, >> >> Found a crash: if we add the route via fe80:: * after* the interface >> upping - vpp crashes. >> >> For example: >> >> DBGvpp# create tap >> >> tap0 >> >> DBGvpp# set int state tap0 up >> >> DBGvpp# ip route add fa::1/120 via fe80::1 tap0 >> >> make: *** [Makefile:537: run] Aborted >> >> >> >> If we swap *set ... up* and *ip route ...* - no crashes. >> >> Could you please explain me if such a situation is possible at all? >> In any case, I believe that vpp should not crash. >> >> Thanks. >> >> >> >> >> >> -- >> >> Best regards >> Stanislav Zaikin >> >> >> >> >>
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