From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeff Garzik <jgarzik@pobox.com>
Subject: Re: v2.6.25: WARNING: at kernel/lockdep.c:2437	__lock_acquire+0xc69/0xfa0()
Date: Sat, 11 Apr 2009 12:10:42 -0400
Message-ID: <49E0C102.4020705@pobox.com>
References: <19f34abd0804200329j3308b081vc0732c3ec5c0b721@mail.gmail.com> <1208782090.7115.179.camel@twins> <480FF821.9050208@gmail.com>
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To: Tejun Heo <htejun@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Vegard Nossum <vegard.nossum@gmail.com>, LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>, IDE/ATA development list <linux-ide@vger.kernel.org>, Alan Cox <alan@lxorguk.ukuu.org.uk>

Tejun Heo wrote:
> Peter Zijlstra wrote:
>> Indeed, quite easy to reproduce:
>>
>> diff --git a/kernel/lockdep.c b/kernel/lockdep.c
>> index 81a4e4a..33901ef 100644
>> --- a/kernel/lockdep.c
>> +++ b/kernel/lockdep.c
>> @@ -2434,6 +2434,13 @@ static int __lock_acquire(struct lockdep_map 
>> *lock, unsigned int subclass,
>>       * the hash, not class->key.
>>       */
>>      id = class - lock_classes;
>> +    if (id >= MAX_LOCKDEP_KEYS) {
>> +        spinlock_t *slock = container_of(lock, spinlock_t, dep_map);
>> +
>> +        printk(KERN_EMERG "magic: %x\n", slock->magic);
>> +        printk(KERN_EMERG "class: %p\n", class);
>> +        printk(KERN_EMERG "id: %u\n", id);
>> +    }
>>      if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
>>          return 0;
>>  
>>
>>
>> gives me:
>>
>> ata3: PATA max PIO4 cmd 0x1e8 ctl 0x3ee irq 11
>> magic: c050cf60
>> class: c7c20e54
>> id: 2265185251
>> ------------[ cut here ]------------
>> WARNING: at /mnt/md0/src/linux-2.6-2/kernel/lockdep.c:2444
>> __lock_acquire+0x57b/0xfd0()
>>
>>
>> Looks like someone is stomping on the spinlock or just passing us
>> garbage.
> 
> Does the attached patch help?
> 
> diff --git a/drivers/ata/pata_legacy.c b/drivers/ata/pata_legacy.c
> index 7af4b29..f7ba234 100644
> --- a/drivers/ata/pata_legacy.c
> +++ b/drivers/ata/pata_legacy.c
> @@ -1037,6 +1037,7 @@ static __init int legacy_init_one(struct legacy_probe *probe)
>  			return 0;
>  		}
>  	}
> +	ata_host_detach(host);
>  fail:
>  	platform_device_unregister(pdev);
>  	return ret;


(going through old, unresolved email)

It looks like this might still be needed?  I never saw an "it works" 
response to this email.

	Jeff