Date: Tue, 14 Dec 2021 23:50:12 -0600 From: Kyle Evans <kevans@freebsd.org> To: Mark Johnston <markj@freebsd.org> Cc: Kristof Provost <kp@freebsd.org>, Gleb Smirnoff <glebius@freebsd.org>, src-committers <src-committers@freebsd.org>, "<dev-commits-src-all@freebsd.org>" <dev-commits-src-all@freebsd.org>, dev-commits-src-main@freebsd.org Subject: Re: git: eb93b99d6986 - main - in_pcb: delay crfree() down into UMA dtor Message-ID: <CACNAnaHF8ERrpW3V0Ac1o-KSymRqm0=LKymiMc=0q3ebcF2RUg@mail.gmail.com> In-Reply-To: <YblUfqAXf1WgVCnL@nuc> References: <202112051847.1B5Il2GP030287@gitrepo.freebsd.org> <28AE53F1-2B22-444B-B1EC-1600FA741FE2@FreeBSD.org> <YblUfqAXf1WgVCnL@nuc>
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On Tue, Dec 14, 2021 at 8:35 PM Mark Johnston <markj@freebsd.org> wrote: > > On Tue, Dec 14, 2021 at 10:42:49PM +0100, Kristof Provost wrote: > > On 5 Dec 2021, at 19:47, Gleb Smirnoff wrote: > > > The branch main has been updated by glebius: > > > > > > URL: > > > https://cgit.FreeBSD.org/src/commit/?id=3Deb93b99d698674e3b1cc7139fda= 98e2b175b8c5b > > > > > > commit eb93b99d698674e3b1cc7139fda98e2b175b8c5b > > > Author: Gleb Smirnoff <glebius@FreeBSD.org> > > > AuthorDate: 2021-12-05 16:47:24 +0000 > > > Commit: Gleb Smirnoff <glebius@FreeBSD.org> > > > CommitDate: 2021-12-05 18:46:37 +0000 > > > > > > in_pcb: delay crfree() down into UMA dtor > > > > > > inpcb lookups, which check inp_cred, work with pcbs that > > > potentially went > > > through in_pcbfree(). So inp_cred should stay valid until SMR > > > guarantees > > > its invisibility to lookups. > > > > > > While here, put the whole inpcb destruction sequence of > > > in_pcbfree(), > > > inpcb_dtor() and inpcb_fini() sequentially. > > > > > > Submitted by: markj > > > Differential revision: https://reviews.freebsd.org/D33273 > > > > > > > For some reason it looks like this commit causes jails to fail to get > > fully cleaned up. > > I can reproduce that trivially with `cd /usr/tests/sys/net ; kyua test > > if_bridge_test:bridge_transmit_ipv4_unicast ; jls -na`. > > > > Note the jails in dying state. > > > > The jails created by that test never go away. It=E2=80=99s as if > > `crfree(inp->inp_cred);` doesn=E2=80=99t actually get called. And indee= d, it > > looks like inpcb_dtor() does not get called at all. > > For SMR zones it won't get called until there's some attempt to reuse a > bucket. There's a fairly tight bound on this in the sense that there > can't be a large number of freed items waiting for the dtor to be > invoked, so the amount of consumed memory should be small, but there's > no bound on how long one might have to wait. I didn't realize that jail > destruction could block waiting for a ucred reference to vanish. > Right, we ran into this problem with wireguard-freebsd, as well; oftentimes, a ucred will be the last prison ref, so we had to hook jail's osd remove method and more aggressively purge wg interfaces that'd otherwise be keeping it alive. > When I tried this patch with poudriere on a large system there was no > problem, but the regression test suite is a different story. I'm not > sure how best to fix this yet. >
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