Messages in this thread | | | Date | Wed, 01 Apr 2009 10:30:30 -0700 | From | Randy Dunlap <> | Subject | Re: 2.6.29 boot hang |
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Rusty Russell wrote: > On Wednesday 01 April 2009 15:21:32 Randy Dunlap wrote: >> Rusty Russell wrote: >>> On Wednesday 01 April 2009 07:15:35 Randy Dunlap wrote: >>>> On a 4-proc x86_64 (HP BladeCenter, AMD CPUs) system, booting 2.6.29 >>>> (or earlier, back to 2.6.28-6921-g873392c) hangs during boot. >>>> >>>> git bisect says: >>>> 873392ca514f87eae39f53b6944caf85b1a047cb is first bad commit >>>> commit 873392ca514f87eae39f53b6944caf85b1a047cb >>>> Author: Rusty Russell <rusty@rustcorp.com.au> >>>> Date: Wed Dec 31 23:54:56 2008 +1030 >>>> >>>> PCI: work_on_cpu: use in drivers/pci/pci-driver.c >>> ... >>> >>>> If I change CONFIG_MICROCODE_AMD=y to CONFIG_MICROCODE_AMD=n & rebuild, >>>> the kernel boots successfully. >>> How very very odd. My first thought was a deadlock with keventd used >>> by work_on_cpu (changed in latest Linus tree), but the microcode code at >>> that version doesn't use work_on_cpu. >> Yep, I thought it a bit odd also. >> >>> So I don't think that's it, but this patch should canonically eliminate it: >>> >>> Subject: work_on_cpu(): rewrite it to create a kernel thread on demand >>> From: Andrew Morton <akpm@linux-foundation.org> >> This patch doesn't apply to 2.6.29-final, but it does apply to 2.6.29-git8, > > Err, it has 14 line offset. But here's an adjusted one.
Sorry, I had a patch hunk failure for some (odd) reason.
2.6.29 + this patch still hang during boot for me. Same symptoms.
Thanks.
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index 1f0c509..08bd795 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -971,20 +971,20 @@ undo: > } > > #ifdef CONFIG_SMP > -static struct workqueue_struct *work_on_cpu_wq __read_mostly; > > struct work_for_cpu { > - struct work_struct work; > + struct completion completion; > long (*fn)(void *); > void *arg; > long ret; > }; > > -static void do_work_for_cpu(struct work_struct *w) > +static int do_work_for_cpu(void *_wfc) > { > - struct work_for_cpu *wfc = container_of(w, struct work_for_cpu, work); > - > + struct work_for_cpu *wfc = _wfc; > wfc->ret = wfc->fn(wfc->arg); > + complete(&wfc->completion); > + return 0; > } > > /** > @@ -995,17 +995,23 @@ static void do_work_for_cpu(struct work_struct *w) > * > * This will return the value @fn returns. > * It is up to the caller to ensure that the cpu doesn't go offline. > + * The caller must not hold any locks which would prevent @fn from completing. > */ > long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) > { > - struct work_for_cpu wfc; > - > - INIT_WORK(&wfc.work, do_work_for_cpu); > - wfc.fn = fn; > - wfc.arg = arg; > - queue_work_on(cpu, work_on_cpu_wq, &wfc.work); > - flush_work(&wfc.work); > - > + struct task_struct *sub_thread; > + struct work_for_cpu wfc = { > + .completion = COMPLETION_INITIALIZER_ONSTACK(wfc.completion), > + .fn = fn, > + .arg = arg, > + }; > + > + sub_thread = kthread_create(do_work_for_cpu, &wfc, "work_for_cpu"); > + if (IS_ERR(sub_thread)) > + return PTR_ERR(sub_thread); > + kthread_bind(sub_thread, cpu); > + wake_up_process(sub_thread); > + wait_for_completion(&wfc.completion); > return wfc.ret; > } > EXPORT_SYMBOL_GPL(work_on_cpu); > @@ -1021,8 +1027,4 @@ void __init init_workqueues(void) > hotcpu_notifier(workqueue_cpu_callback, 0); > keventd_wq = create_workqueue("events"); > BUG_ON(!keventd_wq); > -#ifdef CONFIG_SMP > - work_on_cpu_wq = create_workqueue("work_on_cpu"); > - BUG_ON(!work_on_cpu_wq); > -#endif > }
-- ~Randy
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