Date: Thu, 2 Feb 2017 21:05:55 +0000 (UTC) From: Alan Somers <asomers@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r313108 - stable/11/sys/net Message-ID: <201702022105.v12L5tWn086106@repo.freebsd.org>
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Author: asomers Date: Thu Feb 2 21:05:55 2017 New Revision: 313108 URL: https://svnweb.freebsd.org/changeset/base/313108 Log: MFC r310180, r310327 r310180: Fix panic during lagg destruction with simultaneous status check If you run "ifconfig lagg0 destroy" and "ifconfig lagg0" at the same time a page fault may result. The first process will destroy ifp->if_lagg in lagg_clone_destroy (called by if_clone_destroy). Then the second process will observe that ifp->if_lagg is NULL at the top of lagg_port_ioctl and goto fallback: where it will promptly dereference ifp->if_lagg anyway. The solution is to repeat the NULL check for ifp->if_lagg MFC after: 4 weeks Sponsored by: Spectra Logic Corp Differential Revision: https://reviews.freebsd.org/D8512 r310327: Remove stray debugging code from r310180 Reported by: rstone Pointy hat to: asomers MFC after: 3 weeks X-MFC-with: 310180 Sponsored by: Spectra Logic Corp Modified: stable/11/sys/net/if_lagg.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/net/if_lagg.c ============================================================================== --- stable/11/sys/net/if_lagg.c Thu Feb 2 20:30:50 2017 (r313107) +++ stable/11/sys/net/if_lagg.c Thu Feb 2 21:05:55 2017 (r313108) @@ -1022,7 +1022,7 @@ lagg_port_ioctl(struct ifnet *ifp, u_lon return (error); fallback: - if (lp->lp_ioctl != NULL) + if (lp != NULL && lp->lp_ioctl != NULL) return ((*lp->lp_ioctl)(ifp, cmd, data)); return (EINVAL);
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