From: Jamie Lokier <jamie@shareable.org>
To: RANDAZZO@ddc-web.com
Cc: linux-kernel@vger.kernel.org
Subject: Re: FW: spinlocks dont work
Date: Sat, 14 Feb 2004 01:26:16 +0000 [thread overview]
Message-ID: <20040214012616.GF31199@mail.shareable.org> (raw)
In-Reply-To: <89760D3F308BD41183B000508BAFAC4104B16F74@DDCNYNTD>
RANDAZZO@ddc-web.com wrote:
> Note the following example:
>
> driver 'A' calls spin_lock_irqsave and gets through (but does not call
> ..unlock).
> driver 'B' calls spin_lock_irqsave and gets through???
>
> How can B get through if A did not unlock yet?
Is that code from B an interrupt handler?
If yes, then A should have called spin_lock_irqsave()
Otherwise, is that code from B a softirq or tasklet or timer handler?
If yes, then A should have called spin_lock_bh()
Otherwise, that code from B cannot run unless you are calling
schedule() from A after taking the lock, which is a bug in your code.
-- Jamie
prev parent reply other threads:[~2004-02-14 1:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-02-13 21:12 FW: spinlocks dont work RANDAZZO
2004-02-13 21:34 ` Tim Hockin
2004-02-13 22:41 ` Brian Gerst
2004-02-14 1:22 ` Jamie Lokier
2004-02-14 1:26 ` Jamie Lokier [this message]
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