Date: Tue, 31 May 2022 11:06:57 +0200 From: Dimitry Andric <dim@FreeBSD.org> To: Kristof Provost <kp@freebsd.org> Cc: Gleb Smirnoff <glebius@FreeBSD.org>, "src-committers@freebsd.org" <src-committers@FreeBSD.org>, "dev-commits-src-all@freebsd.org" <dev-commits-src-all@FreeBSD.org>, "dev-commits-src-branches@freebsd.org" <dev-commits-src-branches@FreeBSD.org> Subject: Re: git: 4dfd3ffc4488 - stable/13 - if: avoid interface destroy race Message-ID: <1F175CE2-7649-4899-9CA0-8ADCE9206B6A@FreeBSD.org> In-Reply-To: <202205271637.24RGbHHW010235@gitrepo.freebsd.org> References: <202205271637.24RGbHHW010235@gitrepo.freebsd.org>
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[-- Attachment #1 --] On 27 May 2022, at 18:37, Kristof Provost <kp@freebsd.org> wrote: > > The branch stable/13 has been updated by kp: > > URL: https://cgit.FreeBSD.org/src/commit/?id=4dfd3ffc4488e5e2662cdc40deec17d82432da0b > > commit 4dfd3ffc4488e5e2662cdc40deec17d82432da0b > Author: Kristof Provost <kp@FreeBSD.org> > AuthorDate: 2022-03-27 18:23:25 +0000 > Commit: Kristof Provost <kp@FreeBSD.org> > CommitDate: 2022-05-27 16:25:10 +0000 > > if: avoid interface destroy race > > When we destroy an interface while the jail containing it is being > destroyed we risk seeing a race between if_vmove() and the destruction > code, which results in us trying to move a destroyed interface. > > Protect against this by using the ifnet_detach_sxlock to also covert > if_vmove() (and not just detach). > > PR: 262829 > MFC after: 3 weeks > Differential Revision: https://reviews.freebsd.org/D34704 > > (cherry picked from commit 868bf82153e8ff22f09a8860c872149e0fb6bdef) > --- > sys/net/if.c | 22 ++++++++++++++++++++-- > tests/sys/net/if_clone_test.sh | 29 +++++++++++++++++++++++++++++ > 2 files changed, 49 insertions(+), 2 deletions(-) > > diff --git a/sys/net/if.c b/sys/net/if.c > index d4871ccbc1f7..091e9e64b99f 100644 > --- a/sys/net/if.c > +++ b/sys/net/if.c > @@ -548,7 +548,9 @@ vnet_if_return(const void *unused __unused) > IFNET_WUNLOCK(); > > for (int j = 0; j < i; j++) { > + sx_xlock(&ifnet_detach_sxlock); > if_vmove(pending[j], pending[j]->if_home_vnet); > + sx_xunlock(&ifnet_detach_sxlock); > } > > free(pending, M_IFNET); > @@ -1393,6 +1395,8 @@ if_vmove_loan(struct thread *td, struct ifnet *ifp, char *ifname, int jid) > bool found; > bool shutdown; > > + MPASS(ifindex_table[ifp->if_index].ife_ifnet == ifp); > + > /* Try to find the prison within our visibility. */ > sx_slock(&allprison_lock); > pr = prison_find_child(td->td_ucred->cr_prison, jid); This particular part resulted in errors during one of my universe builds: _.amd64.LINT: /home/dim/src/stable-13/sys/net/if.c:1398:8: error: use of undeclared identifier 'ifindex_table' MPASS(ifindex_table[ifp->if_index].ife_ifnet == ifp); ^ Note that it only seems to happen for the LINT kernels, though. It appears that ifindex_table changed from a VNET define into a global with Gleb's commit https://cgit.freebsd.org/src/commit/?id=80e60e236d85d -Dimitry [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.2 iF0EARECAB0WIQR6tGLSzjX8bUI5T82wXqMKLiCWowUCYpXasQAKCRCwXqMKLiCW ozEuAKCEUzwSbJ3Tp+cVuPG7hzZINycUSQCgvSE2BYGvZYELOuQEcD6RQ+TGJhQ= =qo3m -----END PGP SIGNATURE-----
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