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From: Manfred Spraul <manfred@colorfullife.com>
To: Muli Ben-Yehuda <mulix@mulix.org>
Cc: Oliver Neukum <oliver@neukum.name>, linux-kernel@vger.kernel.org
Subject: Re: question on context of kfree_skb()
Date: Mon, 30 Dec 2002 23:32:49 +0100	[thread overview]
Message-ID: <3E10C991.4060807@colorfullife.com> (raw)

Mulix wrote:

>dev_kfree_skb_any() should be called when you could be either
>executing in interrupt context or not. 
>
dev_kfree_skb_any() can misdetect the context: You must not use the 
function if you hold an irq spinlock and you might be running from BH or 
process context.

cpu 1:    cpu 2:
acquire one of the networking bh lock
             acquire the driver spin_lock_irq()
hardware interrupt
try to acquire the driver irq spinlock
--> spin.
              dev_kfree_skb_any(): !in_irq(), calls kfree_skb
              kfree_skb tries to acquire the network lock that
              cpu 1 owns
              --> spin.

And deadlock.

--
    Manfred




             reply	other threads:[~2002-12-30 22:27 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-12-30 22:32 Manfred Spraul [this message]
2002-12-31  0:57 ` question on context of kfree_skb() Oliver Neukum
2002-12-31  9:31   ` Manfred Spraul
  -- strict thread matches above, loose matches on Subject: below --
2002-12-30 18:32 Oliver Neukum
2002-12-30 22:26 ` Muli Ben-Yehuda

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