On 20-12-2006 03:13, Ben Greear wrote:
> This is from 2.6.18.2 kernel with my patch set. The MAC-VLANs are in
> active use.
> From the backtrace, I am thinking this might be a generic problem,
> however.
>
> Any ideas about what this could be? It seems to be reproducible every
> day or
> two, but no known way to make it happen quickly...
>
> Kernel is SMP, PREEMPT.
>
>
> Dec 19 04:49:33 localhost kernel: BUG: soft lockup detected on CPU#0!
> Dec 19 04:49:33 localhost kernel: [<78104252>] show_trace+0x12/0x20
> Dec 19 04:49:33 localhost kernel: [<78104929>] dump_stack+0x19/0x20
> Dec 19 04:49:33 localhost kernel: [<7814c88b>] softlockup_tick+0x9b/0xd0
> Dec 19 04:49:33 localhost kernel: [<7812a992>] run_local_timers+0x12/0x20
> Dec 19 04:49:33 localhost kernel: [<7812ac08>]
> update_process_times+0x38/0x80
> Dec 19 04:49:33 localhost kernel: [<78112796>]
> smp_apic_timer_interrupt+0x66/0x70
> Dec 19 04:49:33 localhost kernel: [<78103baa>]
> apic_timer_interrupt+0x2a/0x30
> Dec 19 04:49:33 localhost kernel: [<78354e8c>] _read_lock+0x3c/0x50
> Dec 19 04:49:33 localhost kernel: [<78331f42>] ip_check_mc+0x22/0xb0
> Dec 19 04:49:33 localhost kernel: [<783068bf>] ip_route_input+0x17f/0xef0
> Dec 19 04:49:33 localhost kernel: [<78309c59>] ip_rcv+0x349/0x580
Hello,
This log isn't probably enough to tell with certainty
which lock is to blame. We can see it's taken from
some timer during ip_check_mc() but this
read_lock(&in_dev->mc_list_lock) doesn't seem to
be used in timers for writing.
Maybe if you would wait a few minutes or tried
SysRq a oops could tell more.
Looking at igmp.c I've found one suspicious place
and here is a patch proposal included, but it may
be not your case. Anyway you could also try to
change this above mentioned read_lock and
read_unlock to _bh versions - maybe I missed
something.
If it doesn't help, I hope lockdep will be more
precise when you'll upgrade to 2.6.19 or higher.
Regards,
Jarek P.
---
[PATCH] igmp: spin_lock_bh in timer
igmp_timer_expire() uses spin_lock(&im->lock)
but this lock is also taken by other igmp timers,
so it should be changed to bh version.
Signed-off-by: Jarek Poplawski <[EMAIL PROTECTED]>
---
diff -Nurp linux-2.6.20-rc1-/net/ipv4/igmp.c linux-2.6.20-rc1/net/ipv4/igmp.c
--- linux-2.6.20-rc1-/net/ipv4/igmp.c 2006-12-16 20:37:18.000000000 +0100
+++ linux-2.6.20-rc1/net/ipv4/igmp.c 2006-12-21 22:57:30.000000000 +0100
@@ -727,7 +727,7 @@ static void igmp_timer_expire(unsigned l
struct ip_mc_list *im=(struct ip_mc_list *)data;
struct in_device *in_dev = im->interface;
- spin_lock(&im->lock);
+ spin_lock_bh(&im->lock);
im->tm_running=0;
if (im->unsolicit_count) {
@@ -735,7 +735,7 @@ static void igmp_timer_expire(unsigned l
igmp_start_timer(im, IGMP_Unsolicited_Report_Interval);
}
im->reporter = 1;
- spin_unlock(&im->lock);
+ spin_unlock_bh(&im->lock);
if (IGMP_V1_SEEN(in_dev))
igmp_send_report(in_dev, im, IGMP_HOST_MEMBERSHIP_REPORT);
-
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