Messages in this thread Patch in this message | | | Date | Tue, 02 May 2006 15:45:58 +0200 | From | Patrick McHardy <> | Subject | Re: [netfilter-core] [lockup] 2.6.17-rc3: netfilter/sctp: lockup in sctp_new(), do_basic_checks() |
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Ingo Molnar wrote: > running an "isic" stresstest on and against a testbox [which, amongst > other things, generates random incoming and outgoing packets] on > 2.6.17-rc3 (and 2.6.17-rc3-mm1) over gigabit results in a reproducible > lockup, after 5-10 minutes of runtime: > > BUG: soft lockup detected on CPU#0! > [<c0104e7f>] show_trace+0xd/0xf > [<c0104e96>] dump_stack+0x15/0x17 > [<c015ad02>] softlockup_tick+0xc5/0xd9 > [<c0134c02>] run_local_timers+0x22/0x24 > [<c0134fb7>] update_process_times+0x40/0x65 > [<c011aa56>] smp_apic_timer_interrupt+0x58/0x60 > [<c010492b>] apic_timer_interrupt+0x27/0x2c > [<c0f00df9>] sctp_new+0x8b/0x235 > [...] > > this is with FRAME_POINTERS enabled, so it's an exact stacktrace. > > the lockup is at: > > (gdb) list *0xc0f00df9 > 0xc0f00df9 is in sctp_new > (net/ipv4/netfilter/ip_conntrack_proto_sctp.c:444). > 439 > 440 sh = skb_header_pointer(skb, iph->ihl * 4, sizeof(_sctph), &_sctph); > 441 if (sh == NULL) > 442 return 0; > 443 > 444 if (do_basic_checks(conntrack, skb, map) != 0) > 445 return 0; > 446 > 447 /* If an OOTB packet has any of these chunks discard (Sec 8.4) */ > 448 if ((test_bit (SCTP_CID_ABORT, (void *)map)) > > most likely somewhere within do_basic_checks(). [whose stack entry is > obscured by the irq entry, so it's not in the stackdump.] I have SCTP > turned on:
Yes, it seems like it doesn't make any forward progress in for_each_sctp_chunk() because the chunk length is zero. Can you try this patch please?
[NETFILTER]: Fix endless loop in SCTP conntrack
When a chunk length is zero, for_each_sctp_chunk() doesn't make any forward progress and loops forever. A chunk length of 0 is invalid, so just abort in that case.
Reported by Ingo Molnar <mingo@elte.hu>.
Signed-off-by: Patrick McHardy <kaber@trash.net>
--- commit 32491b3d62bc8c3ff2400deebd46972ebc7332af tree 7249133ec32c18f4e6f989560e8d86b5e2e2cf0c parent 462f3ddd384045c731b3268a1b9c91c834a5a68a author Patrick McHardy <kaber@trash.net> Tue, 02 May 2006 15:44:30 +0200 committer Patrick McHardy <kaber@trash.net> Tue, 02 May 2006 15:44:30 +0200
net/ipv4/netfilter/ip_conntrack_proto_sctp.c | 4 ++-- net/netfilter/nf_conntrack_proto_sctp.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/net/ipv4/netfilter/ip_conntrack_proto_sctp.c b/net/ipv4/netfilter/ip_conntrack_proto_sctp.c index 5259abd..ebd4ecf 100644 --- a/net/ipv4/netfilter/ip_conntrack_proto_sctp.c +++ b/net/ipv4/netfilter/ip_conntrack_proto_sctp.c @@ -209,8 +209,8 @@ static int sctp_print_conntrack(struct s #define for_each_sctp_chunk(skb, sch, _sch, offset, count) \ for (offset = skb->nh.iph->ihl * 4 + sizeof(sctp_sctphdr_t), count = 0; \ offset < skb->len && \ - (sch = skb_header_pointer(skb, offset, sizeof(_sch), &_sch)); \ - offset += (htons(sch->length) + 3) & ~3, count++) + (sch = skb_header_pointer(skb, offset, sizeof(_sch), &_sch)) && \ + sch->length; offset += (htons(sch->length) + 3) & ~3, count++) /* Some validity checks to make sure the chunks are fine */ static int do_basic_checks(struct ip_conntrack *conntrack, diff --git a/net/netfilter/nf_conntrack_proto_sctp.c b/net/netfilter/nf_conntrack_proto_sctp.c index 9cccc32..2e34436 100644 --- a/net/netfilter/nf_conntrack_proto_sctp.c +++ b/net/netfilter/nf_conntrack_proto_sctp.c @@ -213,8 +213,8 @@ static int sctp_print_conntrack(struct s #define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count) \ for (offset = dataoff + sizeof(sctp_sctphdr_t), count = 0; \ offset < skb->len && \ - (sch = skb_header_pointer(skb, offset, sizeof(_sch), &_sch)); \ - offset += (htons(sch->length) + 3) & ~3, count++) + (sch = skb_header_pointer(skb, offset, sizeof(_sch), &_sch)) && \ + sch->length; offset += (htons(sch->length) + 3) & ~3, count++) /* Some validity checks to make sure the chunks are fine */ static int do_basic_checks(struct nf_conn *conntrack, | |