Messages in this thread | | | Date | Thu, 6 Mar 2008 13:36:32 -0800 | From | Andrew Morton <> | Subject | Re: 2.6.25-rc3-git3: Reported regressions from 2.6.24 |
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On Thu, 6 Mar 2008 21:59:51 +0100 Ingo Molnar <mingo@elte.hu> wrote:
> > * Andrew Morton <akpm@linux-foundation.org> wrote: > > > I'd love to poke around in kgdb (what does kthread_stop_info.k point > > at?) but it seems that -mm's copy of kgdb got taken away when I wasn't > > looking. Can I have it back please? > > it's in the full x86.git or you can pick up the kgdb-light tree: > > http://people.redhat.com/mingo/kgdb-light.git/README >
We'll see.
Meanwhile, further investigation show that cpu_callback() (the one in kernel/softlockup.c) is waiting on this thread:
watchdog/1 R running task 0 8 2 task_struct:ffff81025f1089e0 ffff81025f10deb0 0000000000000046 0000000000000000 0000000000000246 ffff81025f10de20 ffff81025f1089e0 ffff81025f1080c0 ffff81025f108d30 000000015f10de50 00000000ffff2adf ffffffffffffffff ffffffffffffffff Call Trace: [<ffffffff80263290>] ? watchdog+0x0/0x1dc [<ffffffff802632d6>] watchdog+0x46/0x1dc [<ffffffff80263290>] ? watchdog+0x0/0x1dc [<ffffffff8024704d>] kthread+0x44/0x6b [<ffffffff8020cd88>] child_rip+0xa/0x12 [<ffffffff80247009>] ? kthread+0x0/0x6b [<ffffffff8020cd7e>] ? child_rip+0x0/0x12
kthread_stop_info.k=ffff81025f1089e0
(gdb) l *0xffffffff802632d6 0xffffffff802632d6 is in watchdog (kernel/softlockup.c:229). 224 */ 225 while (!kthread_should_stop()) { 226 touch_softlockup_watchdog(); 227 schedule(); 228 229 if (kthread_should_stop()) 230 break; 231 232 if (this_cpu == check_cpu) { 233 if (sysctl_hung_task_timeout_secs)
so this watchdog thread seems to be runnable, but not running. What would cause this?
The only other runnable task is
events/2 R running task 0 29 2 task_struct:ffff81025f2da300 ffff81025f2e3ec0 0000000000000046 0000000000000286 ffff81000102ebc0 ffff81000102ebe0 ffff81025f2da300 ffff81025f147380 ffff81025f2da650 000000025f2e3e60 00000000ffff3310 ffff81000102ebc8 ffff81025f20e440 Call Trace: [<ffffffff802442ce>] ? worker_thread+0x0/0xe5 [<ffffffff80244371>] worker_thread+0xa3/0xe5 [<ffffffff80247364>] ? autoremove_wake_function+0x0/0x36 [<ffffffff802442ce>] ? worker_thread+0x0/0xe5 [<ffffffff8024704d>] kthread+0x44/0x6b [<ffffffff8020cd88>] child_rip+0xa/0x12 [<ffffffff80247009>] ? kthread+0x0/0x6b [<ffffffff8020cd7e>] ? child_rip+0x0/0x12
which is on a different CPU.
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