Author: hselasky Date: Mon Oct 15 10:29:29 2018 New Revision: 339358 URL: https://svnweb.freebsd.org/changeset/base/339358
Log: Fix deadlock when destroying VLANs. Synchronizing the epoch before freeing the multicast addresses while holding the VLAN_XLOCK() might lead to a deadlock. Use deferred freeing of the VLAN multicast addresses to resolve deadlock. Backtrace: Thread1: epoch_block_handler_preempt() ck_epoch_synchronize_wait() epoch_wait_preempt() vlan_setmulti() vlan_ioctl() in6m_release_task() gtaskqueue_run_locked() gtaskqueue_thread_loop() fork_exit() fork_trampoline() Thread2: sleepq_switch() sleepq_wait() _sx_xlock_hard() _sx_xlock() in6_leavegroup() in6_purgeaddr() if_purgeaddrs() if_detach_internal() if_detach() vlan_clone_destroy() if_clone_destroyif() if_clone_destroy() ifioctl() kern_ioctl() sys_ioctl() amd64_syscall() fast_syscall_common() syscall() Differential revision: https://reviews.freebsd.org/D17496 Reviewed by: slavash, mmacy Approved by: re (kib) Sponsored by: Mellanox Technologies Modified: head/sys/net/if_vlan.c Modified: head/sys/net/if_vlan.c ============================================================================== --- head/sys/net/if_vlan.c Mon Oct 15 10:25:34 2018 (r339357) +++ head/sys/net/if_vlan.c Mon Oct 15 10:29:29 2018 (r339358) @@ -153,6 +153,7 @@ struct ifvlantrunk { struct vlan_mc_entry { struct sockaddr_dl mc_addr; CK_SLIST_ENTRY(vlan_mc_entry) mc_entries; + struct epoch_context mc_epoch_ctx; }; struct ifvlan { @@ -317,6 +318,13 @@ VNET_DEFINE_STATIC(struct if_clone *, vlan_cloner); #define HASH(n, m) ((((n) >> 8) ^ ((n) >> 4) ^ (n)) & (m)) static void +vlan_mc_free(struct epoch_context *ctx) +{ + struct vlan_mc_entry *mc = __containerof(ctx, struct vlan_mc_entry, mc_epoch_ctx); + free(mc, M_VLAN); +} + +static void vlan_inithash(struct ifvlantrunk *trunk) { int i, n; @@ -572,8 +580,7 @@ vlan_setmulti(struct ifnet *ifp) while ((mc = CK_SLIST_FIRST(&sc->vlan_mc_listhead)) != NULL) { CK_SLIST_REMOVE_HEAD(&sc->vlan_mc_listhead, mc_entries); (void)if_delmulti(ifp_p, (struct sockaddr *)&mc->mc_addr); - NET_EPOCH_WAIT(); - free(mc, M_VLAN); + epoch_call(net_epoch_preempt, &mc->mc_epoch_ctx, vlan_mc_free); } /* Now program new ones. */ @@ -1485,8 +1492,7 @@ vlan_unconfig_locked(struct ifnet *ifp, int departing) error); } CK_SLIST_REMOVE_HEAD(&ifv->vlan_mc_listhead, mc_entries); - NET_EPOCH_WAIT(); - free(mc, M_VLAN); + epoch_call(net_epoch_preempt, &mc->mc_epoch_ctx, vlan_mc_free); } vlan_setflags(ifp, 0); /* clear special flags on parent */ _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
