Hi Zhang, I'd expect the interface deletion to happen under the worker barrier. VPP workers should drain all their in-flight packets before entering the barrier, so it should not be possible for the interface to disappear between your node and ip4-lookup. Or am I missing something? What I have seen happening is you'd have some data structure where you keep the interface index that you use in your node, and this data is not updated when the interface is removed. Regarding your proposal, I suspect an issue could be when we reuse the sw_if_index: if you del a sw_interface and then add a new one, chances are you'll be reusing the same index, but fib_index might be different.
Best ben > -----Original Message----- > From: vpp-dev@lists.fd.io <vpp-dev@lists.fd.io> On Behalf Of Zhang Dongya > Sent: Tuesday, November 29, 2022 3:45 > To: vpp-dev@lists.fd.io > Subject: Re: [vpp-dev] possible use deleted sw if index in ip4-lookup and > cause crash > > > I have found a solution and it can solve the crash issue. > > In ip4_sw_interface_add_del which is a callback for interface deletion, we > may set the fib index of the removed interface to 0 (default fib) instead > of ~0. This behavior is same with interface creation. > > > > Zhang Dongya via lists.fd.io <http://lists.fd.io> > <fortitude.zhang=gmail....@lists.fd.io <mailto:gmail....@lists.fd.io> > 于 > 2022年11月28日周一 19:41写道： > > > Hi list, > > Recently I encountered a vpp crash with my plugin enabled, after > some investigation I find it may related with l3 sub interface delete > while my process node add work to ip4-lookup node. > > > Intuitively I think it may related to a barrier usage but I tried > to fix by add some check in my process node to guard the case that l3 sub > interface is deleted. however the crash still exists. > > Finally I think it should be related to a pattern like this: > > 1, my process node adds a pkt by using put_frame_to_node to ip4- > lookup directly, which set the rx interface to the l3 sub interface > created before. > > 2, my control plane agent (using govpp) delete the l3 sub > interface. (it should be handled in vpp api-process node) > > 3, vpp schedule pending nodes. since the rx interface is deleted, > vpp can't get a valid fib index and there is not check in the following > ip4_fib_forwarding_lookup, so it crash with abort. > > I think vpp may schedule my process node(timeout driven) and api- > process node one over one, then it will schedule the pending nodes. > > Should I add some check in ip4-lookup or there are better way of > sending pkt in ctrl process not correct ? > > Thanks a lot. > > > > > > > >
-=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#22255): https://lists.fd.io/g/vpp-dev/message/22255 Mute This Topic: https://lists.fd.io/mt/95307938/21656 Group Owner: vpp-dev+ow...@lists.fd.io Unsubscribe: https://lists.fd.io/g/vpp-dev/leave/1480452/21656/631435203/xyzzy [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
