Date: Fri, 4 Dec 2015 20:34:07 +0100 From: Hans Petter Selasky <hps@selasky.org> To: "Alexander V. Chernikov" <melifaro@freebsd.org>, Adrian Chadd <adrian@freebsd.org> Cc: FreeBSD Net <freebsd-net@freebsd.org>, freebsd-current <freebsd-current@freebsd.org>, Randall Stewart <rrs@netflix.com> Subject: Re: panic in arptimer in r289937 Message-ID: <5661EAAF.1010906@selasky.org> In-Reply-To: <1733241446303675@web19h.yandex.ru> References: <CAJ-VmonvVyTNuYv_as41yPCFdfR5T3FE45DP9MKAc-eyzXzPUg@mail.gmail.com> <2739461446298483@web2h.yandex.ru> <CAJ-Vmo=JjHonDqOYK%2BJDaf9581dRU5_KoaSTnY27JnzQm0v56w@mail.gmail.com> <1733241446303675@web19h.yandex.ru>
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This is a multi-part message in MIME format. --------------010400080206050505080202 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Hi Adrian, On 10/31/15 16:01, Alexander V. Chernikov wrote: > > > 31.10.2015, 16:46, "Adrian Chadd" <adrian@freebsd.org>: >> On 31 October 2015 at 09:34, Alexander V. Chernikov >> <melifaro@freebsd.org> wrote: >>> 31.10.2015, 05:32, "Adrian Chadd" <adrian@freebsd.org>: >>>> Hiya, >>>> >>>> Here's a panic from arptimer: >>> Hi Adrian, >>> >>> As far as I see, line 205 in if_ether.c is IF_AFDATA_LOCK(ifp) which happens after LLE_WUNLOCK(). >>> So, it looks like (pre-cached) ifp had been freed before locking ifdata. >>> Do you have any more details on that? (e.g. was some interface detached at that moment, is it reproducible, etc..) >>> >>> From a quick glance, potential use-after-free has been possible for quite a long time, but I wonder why it hasn't been observed before. >>> Probably lltable_free() changes might have triggered that. >>> >>> I'll take a deeper look on that and reply. >> Observed on an idle box with projects/hps_head too: > panic: bogus refcnt 0 on lle 0xfffff8016508ca00 > cpuid = 7 > KDB: stack backtrace: > db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe03e4e8c7e0 > vpanic() at vpanic+0x182/frame 0xfffffe03e4e8c860 > kassert_panic() at kassert_panic+0x126/frame 0xfffffe03e4e8c8d0 > llentry_free() at llentry_free+0x136/frame 0xfffffe03e4e8c900 > arptimer() at arptimer+0x20e/frame 0xfffffe03e4e8c950 > softclock_call_cc() at softclock_call_cc+0x170/frame 0xfffffe03e4e8c9c0 > softclock() at softclock+0x47/frame 0xfffffe03e4e8c9e0 > intr_event_execute_handlers() at intr_event_execute_handlers+0x96/frame 0xfffffe03e4e8ca20 > ithread_loop() at ithread_loop+0xa6/frame 0xfffffe03e4e8ca70 > fork_exit() at fork_exit+0x84/frame 0xfffffe03e4e8cab0 > fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe03e4e8cab0 > --- trap 0, rip = 0, rsp = 0, rbp = 0 --- Looks like callout_reset() must be examined too, and was missed by: https://svnweb.freebsd.org/changeset/base/290805 Can you try the attached patch? Randall: Can you fix this ASAP? --HPS --------------010400080206050505080202 Content-Type: text/x-patch; name="callout_reset_arptimer.diff" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="callout_reset_arptimer.diff" diff --git a/sys/dev/oce/oce_if.c b/sys/dev/oce/oce_if.c index 826cd3c..1cca876 100644 --- a/sys/dev/oce/oce_if.c +++ b/sys/dev/oce/oce_if.c @@ -343,7 +343,7 @@ oce_attach(device_t dev) callout_init(&sc->timer, 1); rc = callout_reset(&sc->timer, 2 * hz, oce_local_timer, sc); - if (rc) + if (rc > 0) goto stats_free; return 0; diff --git a/sys/netinet/if_ether.c b/sys/netinet/if_ether.c index dfba0b2..0aec1c4 100644 --- a/sys/netinet/if_ether.c +++ b/sys/netinet/if_ether.c @@ -420,7 +420,7 @@ arpresolve_full(struct ifnet *ifp, int is_gw, int create, struct mbuf *m, la->la_expire = time_uptime; canceled = callout_reset(&la->lle_timer, hz * V_arpt_down, arptimer, la); - if (canceled) + if (canceled > 0) LLE_REMREF(la); la->la_asked++; LLE_WUNLOCK(la); @@ -1084,7 +1084,7 @@ arp_mark_lle_reachable(struct llentry *la) la->la_expire = time_uptime + V_arpt_keep; canceled = callout_reset(&la->lle_timer, hz * V_arpt_keep, arptimer, la); - if (canceled) + if (canceled > 0) LLE_REMREF(la); } la->la_asked = 0; --------------010400080206050505080202--
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