Hi, On 12/29/11, John Baldwin <[email protected]> wrote: > Author: jhb > Date: Thu Dec 29 20:41:16 2011 > New Revision: 228969 > URL: http://svn.freebsd.org/changeset/base/228969 > > Log: > Defer the work of freeing IPv4 multicast options from a socket to an > asychronous task. This avoids tearing down multicast state including > sending IGMP leave messages and reprogramming MAC filters while holding > the per-protocol global pcbinfo lock that is used in the receive path of > packet processing. > > Reviewed by: rwatson > MFC after: 1 month > > Modified: > head/sys/netinet/in_mcast.c > head/sys/netinet/ip_var.h > > Modified: head/sys/netinet/in_mcast.c > ============================================================================== > --- head/sys/netinet/in_mcast.c Thu Dec 29 19:01:29 2011 > (r228968) > +++ head/sys/netinet/in_mcast.c Thu Dec 29 20:41:16 2011 > (r228969) > @@ -46,6 +46,7 @@ __FBSDID("$FreeBSD$"); > #include <sys/protosw.h> > #include <sys/sysctl.h> > #include <sys/ktr.h> > +#include <sys/taskqueue.h> > #include <sys/tree.h> > > #include <net/if.h> > @@ -144,6 +145,8 @@ static void inm_purge(struct in_multi *) > static void inm_reap(struct in_multi *); > static struct ip_moptions * > inp_findmoptions(struct inpcb *); > +static void inp_freemoptions_internal(struct ip_moptions *); > +static void inp_gcmoptions(void *, int); > static int inp_get_source_filters(struct inpcb *, struct sockopt *); > static int inp_join_group(struct inpcb *, struct sockopt *); > static int inp_leave_group(struct inpcb *, struct sockopt *); > @@ -179,6 +182,10 @@ static SYSCTL_NODE(_net_inet_ip_mcast, O > CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_ip_mcast_filters, > "Per-interface stack-wide source filters"); > > +static STAILQ_HEAD(, ip_moptions) imo_gc_list = > + STAILQ_HEAD_INITIALIZER(imo_gc_list); > +static struct task imo_gc_task = TASK_INITIALIZER(0, inp_gcmoptions, NULL); > + > /* > * Inline function which wraps assertions for a valid ifp. > * The ifnet layer will set the ifma's ifp pointer to NULL if the ifp > @@ -1518,17 +1525,29 @@ inp_findmoptions(struct inpcb *inp) > } > > /* > - * Discard the IP multicast options (and source filters). > + * Discard the IP multicast options (and source filters). To minimize > + * the amount of work done while holding locks such as the INP's > + * pcbinfo lock (which is used in the receive path), the free > + * operation is performed asynchronously in a separate task. > * > * SMPng: NOTE: assumes INP write lock is held. > */ > void > inp_freemoptions(struct ip_moptions *imo) > { > - struct in_mfilter *imf; > - size_t idx, nmships; > > KASSERT(imo != NULL, ("%s: ip_moptions is NULL", __func__)); > + IN_MULTI_LOCK(); > + STAILQ_INSERT_TAIL(&imo_gc_list, imo, imo_link); > + IN_MULTI_UNLOCK(); > + taskqueue_enqueue(taskqueue_thread, &imo_gc_task); > +} > + > +static void > +inp_freemoptions_internal(struct ip_moptions *imo) > +{ > + struct in_mfilter *imf; > + size_t idx, nmships; > > nmships = imo->imo_num_memberships; > for (idx = 0; idx < nmships; ++idx) { > @@ -1546,6 +1565,22 @@ inp_freemoptions(struct ip_moptions *imo > free(imo, M_IPMOPTS); > } > > +static void > +inp_gcmoptions(void *context, int pending) > +{ > + struct ip_moptions *imo; > + > + IN_MULTI_LOCK(); > + while (!STAILQ_EMPTY(&imo_gc_list)) { > + imo = STAILQ_FIRST(&imo_gc_list); > + STAILQ_REMOVE_HEAD(&imo_gc_list, imo_link); > + IN_MULTI_UNLOCK(); > + inp_freemoptions_internal(imo); > + IN_MULTI_LOCK(); > + } > + IN_MULTI_UNLOCK(); > +} > + > /* > * Atomically get source filters on a socket for an IPv4 multicast group. > * Called with INP lock held; returns with lock released. > > Modified: head/sys/netinet/ip_var.h > ============================================================================== > --- head/sys/netinet/ip_var.h Thu Dec 29 19:01:29 2011 (r228968) > +++ head/sys/netinet/ip_var.h Thu Dec 29 20:41:16 2011 (r228969) > @@ -93,6 +93,7 @@ struct ip_moptions { > u_short imo_max_memberships; /* max memberships this socket */ > struct in_multi **imo_membership; /* group memberships */ > struct in_mfilter *imo_mfilters; /* source filters */ > + STAILQ_ENTRY(ip_moptions) imo_link; > }; > > struct ipstat { >
I have been observing panics like below after recent upgrade on VIMAGE kernel:
#0 doadump (textdump=-2022567936) at pcpu.h:244
#1 0x8051b739 in db_fncall (dummy1=1, dummy2=0, dummy3=-2127531040,
dummy4=0x872b2920 "")
at /home/golub/freebsd/base/head/sys/ddb/db_command.c:573
#2 0x8051bb31 in db_command (last_cmdp=0x8112eefc, cmd_table=0x0, dopager=1)
at /home/golub/freebsd/base/head/sys/ddb/db_command.c:449
#3 0x8051bc8a in db_command_loop () at
/home/golub/freebsd/base/head/sys/ddb/db_command.c:502
#4 0x8051dc7d in db_trap (type=12, code=0)
at /home/golub/freebsd/base/head/sys/ddb/db_main.c:229
#5 0x80a82566 in kdb_trap (type=12, code=0, tf=0x872b2bbc)
at /home/golub/freebsd/base/head/sys/kern/subr_kdb.c:629
#6 0x80ddd26f in trap_fatal (frame=0x872b2bbc, eva=24)
at /home/golub/freebsd/base/head/sys/i386/i386/trap.c:1014
#7 0x80ddd347 in trap_pfault (frame=0x872b2bbc, usermode=0, eva=24)
at /home/golub/freebsd/base/head/sys/i386/i386/trap.c:835
#8 0x80dde411 in trap (frame=0x872b2bbc)
at /home/golub/freebsd/base/head/sys/i386/i386/trap.c:547
#9 0x80dc7c6c in calltrap () at
/home/golub/freebsd/base/head/sys/i386/i386/exception.s:169
#10 0x80b6f1fd in igmp_change_state (inm=0x8ae70480)
at /home/golub/freebsd/base/head/sys/netinet/igmp.c:2595
#11 0x80b76f68 in in_leavegroup_locked (inm=0x8ae70480, imf=0x8a655a00)
at /home/golub/freebsd/base/head/sys/netinet/in_mcast.c:1239
#12 0x80b76fbd in in_leavegroup (inm=0x8ae70480, imf=0x8a655a00)
at /home/golub/freebsd/base/head/sys/netinet/in_mcast.c:1184
#13 0x80b770b4 in inp_gcmoptions (context=0x0, pending=1)
at /home/golub/freebsd/base/head/sys/netinet/in_mcast.c:1554
#14 0x80a8ff2b in taskqueue_run_locked (queue=0x87594880)
at /home/golub/freebsd/base/head/sys/kern/subr_taskqueue.c:308
#15 0x80a90987 in taskqueue_thread_loop (arg=0x81186bcc)
at /home/golub/freebsd/base/head/sys/kern/subr_taskqueue.c:497
#16 0x80a1b2d8 in fork_exit (callout=0x80a90920
<taskqueue_thread_loop>, arg=0x81186bcc,
frame=0x872b2d28) at /home/golub/freebsd/base/head/sys/kern/kern_fork.c:992
#17 0x80dc7d14 in fork_trampoline ()
at /home/golub/freebsd/base/head/sys/i386/i386/exception.s:276
(kgdb) fr 10
#10 0x80b6f1fd in igmp_change_state (inm=0x8ae70480)
at /home/golub/freebsd/base/head/sys/netinet/igmp.c:2595
2595 V_state_change_timers_running = 1;
(kgdb) l
2590 ("%s: enqueue record =
%d", __func__,
2591 retval));
2592
2593 inm->inm_state = IGMP_LEAVING_MEMBER;
2594 inm->inm_sctimer = 1;
2595 V_state_change_timers_running = 1;
2596 syncstates = 0;
2597 }
2598 break;
2599 }
VNET context is not set at that point.
The attached patch fixes the issue for me. Not sure about inm->inm_ifp
!= NULL assumption but I need interface to get vnet :-).
BTW, in igmp_change_state() this looks for me a bit strange:
if (ifp != NULL) {
/*
* Sanity check that netinet's notion of ifp is the
* same as net's.
*/
KASSERT(inm->inm_ifp == ifp, ("%s: bad ifp", __func__));
}
IGMP_LOCK();
igi = ((struct in_ifinfo *)ifp->if_afdata[AF_INET])->ii_igmp;
The check ifp != NULL suggests that ifp may be NULL, but then it will
panic at the last shown line.
--
Mikolaj Golub
in_mcast.c.inp_gcmoptions.patch
Description: Binary data
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