Date: Mon, 29 Oct 2018 13:17:41 +0000 (UTC) From: Hans Petter Selasky <hselasky@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r339859 - stable/12/sys/net Message-ID: <201810291317.w9TDHf7F000637@repo.freebsd.org>
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Author: hselasky Date: Mon Oct 29 13:17:41 2018 New Revision: 339859 URL: https://svnweb.freebsd.org/changeset/base/339859 Log: MFC r339588: Resolve deadlock between epoch(9) and various network interface SX-locks, during if_purgeaddrs(), by not allowing to hold the epoch read lock over typical network IOCTL code paths. This is a regression issue after r334305. Reviewed by: ae (network) Approved by: re (kib) Differential revision: https://reviews.freebsd.org/D17647 Sponsored by: Mellanox Technologies Modified: stable/12/sys/net/if.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/net/if.c ============================================================================== --- stable/12/sys/net/if.c Mon Oct 29 12:48:30 2018 (r339858) +++ stable/12/sys/net/if.c Mon Oct 29 13:17:41 2018 (r339859) @@ -964,12 +964,18 @@ if_attachdomain1(struct ifnet *ifp) void if_purgeaddrs(struct ifnet *ifp) { - struct ifaddr *ifa, *next; + struct ifaddr *ifa; - NET_EPOCH_ENTER(); - CK_STAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, next) { - if (ifa->ifa_addr->sa_family == AF_LINK) - continue; + while (1) { + NET_EPOCH_ENTER(); + CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { + if (ifa->ifa_addr->sa_family != AF_LINK) + break; + } + NET_EPOCH_EXIT(); + + if (ifa == NULL) + break; #ifdef INET /* XXX: Ugly!! ad hoc just for INET */ if (ifa->ifa_addr->sa_family == AF_INET) { @@ -996,7 +1002,6 @@ if_purgeaddrs(struct ifnet *ifp) IF_ADDR_WUNLOCK(ifp); ifa_free(ifa); } - NET_EPOCH_EXIT(); } /*
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