Date: Fri, 13 Aug 2021 09:07:25 GMT From: Wojciech Macek <wma@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: f61cb12aac8d - main - mroute: fix locking issues Message-ID: <202108130907.17D97Pk2099603@gitrepo.freebsd.org>
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The branch main has been updated by wma: URL: https://cgit.FreeBSD.org/src/commit/?id=f61cb12aac8df8179ac9cbd075272aed6524a505 commit f61cb12aac8df8179ac9cbd075272aed6524a505 Author: Wojciech Macek <wma@FreeBSD.org> AuthorDate: 2021-08-11 07:04:20 +0000 Commit: Wojciech Macek <wma@FreeBSD.org> CommitDate: 2021-08-13 09:06:17 +0000 mroute: fix locking issues In some cases the code may fall into deadlock. Avoid calling epoch_wait when W-lock is taken. Sponsored by: Stormshield Obtained from: Semihalf --- sys/netinet/ip_mroute.c | 58 ++++++++++++++++++++++++------------------------- 1 file changed, 29 insertions(+), 29 deletions(-) diff --git a/sys/netinet/ip_mroute.c b/sys/netinet/ip_mroute.c index b614f74cf7d3..efb34af60d9c 100644 --- a/sys/netinet/ip_mroute.c +++ b/sys/netinet/ip_mroute.c @@ -77,6 +77,7 @@ __FBSDID("$FreeBSD$"); #define _PIM_VT 1 +#include <sys/types.h> #include <sys/param.h> #include <sys/kernel.h> #include <sys/stddef.h> @@ -100,6 +101,7 @@ __FBSDID("$FreeBSD$"); #include <sys/systm.h> #include <sys/time.h> #include <sys/counter.h> +#include <machine/atomic.h> #include <net/if.h> #include <net/if_var.h> @@ -727,7 +729,7 @@ ip_mrouter_init(struct socket *so, int version) curvnet); V_ip_mrouter = so; - ip_mrouter_cnt++; + atomic_add_int(&ip_mrouter_cnt, 1); /* This is a mutex required by buf_ring init, but not used internally */ mtx_init(&V_buf_ring_mtx, "mroute buf_ring mtx", NULL, MTX_DEF); @@ -750,22 +752,20 @@ X_ip_mrouter_done(void) vifi_t vifi; struct bw_upcall *bu; - MRW_WLOCK(); - - if (V_ip_mrouter == NULL) { - MRW_WUNLOCK(); + if (V_ip_mrouter == NULL) return EINVAL; - } /* * Detach/disable hooks to the reset of the system. */ V_ip_mrouter = NULL; - ip_mrouter_cnt--; + atomic_subtract_int(&ip_mrouter_cnt, 1); V_mrt_api_config = 0; MROUTER_WAIT(); + MRW_WLOCK(); + upcall_thread_shutdown = 1; mtx_lock(&V_upcall_thread_mtx); cv_signal(&V_upcall_thread_cv); @@ -896,25 +896,17 @@ add_vif(struct vifctl *vifcp) struct ifnet *ifp; int error; - MRW_WLOCK(); - if (vifcp->vifc_vifi >= MAXVIFS) { - MRW_WUNLOCK(); + + if (vifcp->vifc_vifi >= MAXVIFS) return EINVAL; - } /* rate limiting is no longer supported by this code */ if (vifcp->vifc_rate_limit != 0) { log(LOG_ERR, "rate limiting is no longer supported\n"); - MRW_WUNLOCK(); return EINVAL; } - if (!in_nullhost(vifp->v_lcl_addr)) { - MRW_WUNLOCK(); - return EADDRINUSE; - } - if (in_nullhost(vifcp->vifc_lcl_addr)) { - MRW_WUNLOCK(); + + if (in_nullhost(vifcp->vifc_lcl_addr)) return EADDRNOTAVAIL; - } /* Find the interface with an address in AF_INET family */ if (vifcp->vifc_flags & VIFF_REGISTER) { @@ -932,7 +924,6 @@ add_vif(struct vifctl *vifcp) ifa = ifa_ifwithaddr((struct sockaddr *)&sin); if (ifa == NULL) { NET_EPOCH_EXIT(et); - MRW_WUNLOCK(); return EADDRNOTAVAIL; } ifp = ifa->ifa_ifp; @@ -942,7 +933,6 @@ add_vif(struct vifctl *vifcp) if ((vifcp->vifc_flags & VIFF_TUNNEL) != 0) { CTR1(KTR_IPMF, "%s: tunnels are no longer supported", __func__); - MRW_WUNLOCK(); return EOPNOTSUPP; } else if (vifcp->vifc_flags & VIFF_REGISTER) { ifp = V_multicast_register_if = if_alloc(IFT_LOOP); @@ -952,17 +942,24 @@ add_vif(struct vifctl *vifcp) V_reg_vif_num = vifcp->vifc_vifi; } } else { /* Make sure the interface supports multicast */ - if ((ifp->if_flags & IFF_MULTICAST) == 0) { - MRW_WUNLOCK(); + if ((ifp->if_flags & IFF_MULTICAST) == 0) return EOPNOTSUPP; - } /* Enable promiscuous reception of all IP multicasts from the if */ error = if_allmulti(ifp, 1); - if (error) { - MRW_WUNLOCK(); + if (error) return error; - } + } + + MRW_WLOCK(); + + if (!in_nullhost(vifp->v_lcl_addr)) { + if (ifp) + V_multicast_register_if = NULL; + MRW_WUNLOCK(); + if (ifp) + if_free(ifp); + return EADDRINUSE; } vifp->v_flags = vifcp->vifc_flags; @@ -1014,8 +1011,11 @@ del_vif_locked(vifi_t vifi) if (vifp->v_flags & VIFF_REGISTER) { V_reg_vif_num = VIFI_INVALID; - if_free(V_multicast_register_if); - V_multicast_register_if = NULL; + if (vifp->v_ifp) { + if (vifp->v_ifp == V_multicast_register_if) + V_multicast_register_if = NULL; + if_free(vifp->v_ifp); + } } mtx_destroy(&vifp->v_spin);
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