Re: What's going on with vnets and epairs w/ addresses?
- Reply: Bjoern A. Zeeb: "Re: What's going on with vnets and epairs w/ addresses?"
- Reply: Gleb Smirnoff : "Re: What's going on with vnets and epairs w/ addresses?"
- Reply: Gleb Smirnoff : "Re: What's going on with vnets and epairs w/ addresses?"
- In reply to: Zhenlei Huang : "Re: What's going on with vnets and epairs w/ addresses?"
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Date: Fri, 16 Dec 2022 10:30:57 UTC
Hi, I managed to repeat this issue on CURRENT/14 with this small snip: ------------------------------------------- #!/bin/sh # test jail name n="test_ref_leak" jail -c name=$n path=/ vnet persist # The following line trigger jail pr_ref leak jexec $n ifconfig lo0 inet 127.0.0.1/8 jail -R $n # wait a moment sleep 1 jls -j $n ------------------------------------------- After DDB debugging and tracing , it seems that is triggered by a combine of [1] and [2] [1] https://reviews.freebsd.org/rGfec8a8c7cbe4384c7e61d376f3aa5be5ac895915 <https://reviews.freebsd.org/rGfec8a8c7cbe4384c7e61d376f3aa5be5ac895915> [2] https://reviews.freebsd.org/rGeb93b99d698674e3b1cc7139fda98e2b175b8c5b <https://reviews.freebsd.org/rGeb93b99d698674e3b1cc7139fda98e2b175b8c5b> In [1] the per-VNET uma zone is shared with the global one. `pcbinfo->ipi_zone = pcbstor->ips_zone;` In [2] unref `inp->inp_cred` is deferred called in inpcb_dtor() by uma_zfree_smr() . Unfortunately inps freed by uma_zfree_smr() are cached and inpcb_dtor() is not called immediately , thus leaking `inp->inp_cred` ref and hence `prison->pr_ref`. And it is also not possible to free up the cache by per-VNET SYSUNINIT tcp_destroy / udp_destroy / rip_destroy. Best regards, Zhenlei > On Dec 14, 2022, at 9:56 AM, Zhenlei Huang <zlei@FreeBSD.org> wrote: > > > Hi, > > I also encounter this problem while testing gif tunnel between jails. > > My script is similar but with additional gif tunnels. > > > There are reports in mailing list [1], [2], and another one in forum [3] . > > Seem to be a long standing issue. > > [1] https://lists.freebsd.org/pipermail/freebsd-stable/2016-October/086126.html <https://lists.freebsd.org/pipermail/freebsd-stable/2016-October/086126.html> > [2] https://lists.freebsd.org/pipermail/freebsd-jail/2017-March/003357.html <https://lists.freebsd.org/pipermail/freebsd-jail/2017-March/003357.html> > [3] https://forums.freebsd.org/threads/jails-stopping-prolonged-deaths-starting-networking-et-cetera.84200/ <https://forums.freebsd.org/threads/jails-stopping-prolonged-deaths-starting-networking-et-cetera.84200/> > > > Best regards, > Zhenlei > >> On Dec 14, 2022, at 7:03 AM, Bjoern A. Zeeb <bz@FreeBSD.org <mailto:bz@FreeBSD.org>> wrote: >> >> Hi, >> >> I have used scripts like the below for almost a decade and a half >> (obviously doing more than that in the middle). I haven't used them >> much lately but given other questions I just wanted to fire up a test. >> >> I have an end-November kernel doing the below my eapirs do not come back >> to be destroyed (immediately). >> I have to start polling for the jid to be no longer alive and not in >> dying state (hence added the jls/ifconfig -l lines and removed the >> error checking from ifconfig destroy). That seems sometimes rather >> unreasonably long (to the point I give up). >> >> If I don't configure the addresses below this isn't a problem. >> >> Sorry I am confused by too many incarnations of the code; I know I once >> had a version with an async shutdown path but I believe that never made >> it into mainline, so why are we holding onto the epairs now and not >> nuking the addresses and returning them and are clean? >> >> It's a bit more funny; I added a twiddle loop at the end and nothing >> happened. So I stop the script and start it again and suddenly another >> jail or two have cleaned up and their epairs are back. Something feels >> very very wonky. Play around with this and see ... and let me know if >> you can reproduce this... I quite wonder why some test cases haven't >> gone crazy ... >> >> /bz >> >> ------------------------------------------------------------------------ >> #!/bin/sh >> >> set -e >> set -x >> >> js=`jail -i -c -n jl host.hostname=left.example.net <http://left.example.net/> vnet persist` >> jb=`jail -i -c -n jr host.hostname=right.example.net <http://right.example.net/> vnet persist` >> >> # Create an epair connecting the two machines (vnet jails). >> ep=`ifconfig epair create | sed -e 's/a$//'` >> >> # Add one end to each vnet jail. >> ifconfig ${ep}a vnet ${js} >> ifconfig ${ep}b vnet ${jb} >> >> # Add an IP address on the epairs in each vnet jail. >> # XXX Leave these out and the cleanup seems to work fine. >> jexec ${js} ifconfig ${ep}a inet 192.0.2.1/24 >> jexec ${jb} ifconfig ${ep}b inet 192.0.2.2/24 >> >> # Clean up. >> jail -r ${jb} >> jail -r ${js} >> >> # You want to be able to remove this line ... >> set +e >> >> # No epairs to destroy with addresses configured; fine otherwise. >> ifconfig ${ep}a destroy >> # echo $? >> >> # Add this is here only as things are funny ... >> # jls -av jid dying >> # ifconfig -l >> >> # end >> ------------------------------------------------------------------------ >> >> -- >> Bjoern A. Zeeb r15:7 >> >