Messages in this thread | | | Date | Mon, 10 Sep 2007 21:00:24 +0800 | From | Herbert Xu <> | Subject | Re: 2.6.23-rc5: possible irq lock inversion dependency detected |
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On Sun, Sep 02, 2007 at 01:11:29PM +0000, Christian Kujau wrote: > > after upgrading to 2.6.23-rc5 (and applying davem's fix [0]), lockdep > was quite noisy when I tried to shape my external (wireless) interface: > > [ 6400.534545] FahCore_78.exe/3552 just changed the state of lock: > [ 6400.534713] (&dev->ingress_lock){-+..}, at: [<c038d595>] > netif_receive_skb+0x2d5/0x3c0 > [ 6400.534941] but this lock took another, soft-read-irq-unsafe lock in the > past: > [ 6400.535145] (police_lock){-.--}
This is a genuine dead-lock. The police lock can be taken for reading with softirqs on. If a second CPU tries to take the police lock for writing, while holding the ingress lock, then a softirq on the first CPU can dead-lock when it tries to get the ingress lock.
The minimal fix would be to make sure that we disable BH on the first CPU. Jamal, could you take a look at this please?
Thanks, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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