Re: [patch] Real-Time Preemption, -RT-2.6.9-rc4-mm1-U9

[Michal Schmidt]

Ingo Molnar wrote:
> i have released the -U9 Real-Time Preemption patch, which can be
> downloaded from:
>
>   http://redhat.com/~mingo/realtime-preempt/

I have a reproducible BUG which I first hit in -U9 and it's in -U9.2 
too. It occurs always when a packet hits a REJECT rule in the INPUT 
chain of iptables.
To reproduce: iptables -I INPUT 1 -p tcp --dport 666 -j REJECT
...and telnet your TCP port 666 from the network.


BUG: semaphore recursion deadlock detected!
.. current task ksoftirqd/0/2 is already holding f890a6d4.
c0414ec4 f7c27f64 0000012c 00000001 f7c26000 00000000 f7c27f9c c0121687
       c03c8118 c0121758 c0121ae4 0000000a c03c8118 f7c26000 f7c26000 
00000000
       f7c27fa4 c0121770 f7c27fbc c0121ae4 00000001 fffffff6 f7c26000 
f7c25f70
Call Trace:
 [<c0121687>] ___do_softirq+0x87/0xd0 (32)
 [<c0121758>] _do_softirq+0x8/0x30 (8)
 [<c0121ae4>] ksoftirqd+0x94/0xe0 (4)
 [<c0121770>] _do_softirq+0x20/0x30 (28)
 [<c0121ae4>] ksoftirqd+0x94/0xe0 (8)
 [<c013116a>] kthread+0xaa/0xb0 (24)
 [<c0121a50>] ksoftirqd+0x0/0xe0 (20)
 [<c01310c0>] kthread+0x0/0xb0 (12)
 [<c0103319>] kernel_thread_helper+0x5/0xc (16)
preempt count: 00000003
. 3-level deep critical section nesting:
.. entry 1: down_write+0x1a4/0x1b0 / (ipt_do_table+0x6a/0x330 [ip_tables])
.. entry 2: down_write+0x72/0x1b0 / (ipt_do_table+0x6a/0x330 [ip_tables])
.. entry 3: print_traces+0x1d/0x90 / (show_stack+0x83/0xa0)


Michal
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/