Message-ID: <20021122085441.2127.qmail@email.com>
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From: "dan carpenter" <error27@email.com>
To: linux-kernel@vger.kernel.org
Cc: rusty@rustcorp.com.au, torvalds@transmeta.com, davem@redhat.com
Date: Fri, 22 Nov 2002 03:54:41 -0500
Subject: calling schedule() from interupt context
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1480
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I was running a script to find which functions call schedule() and I across something 
strange.  

In drivers/net/tokenring/3c359.c xl_interrupt() calls schedule().
The path from xl_interupt to schedule is:
xl_rx ==> netif_rx ==> 
kfree_skb ==> __kfree_skb ==> 
secpath_put ==> __secpath_destroy ==> 
xfrm_state_put ==> __xfrm_state_destroy ==> xfrm_put_type ==> 
module_put ==> put_cpu ==> preempt_schedule ==> schedule

The problem is that xl_interrupt is the interrupt handler for the 3c359 driver and
I did not think it was legal to call shedule() from interrupt context.

The second thing is that module_put() has a line that looks like it's decrementing
the module reference count (Is it supposed to do that?):
176                  local_dec(&module->ref[cpu].count);

The third thing I was wondering is:  xl_interupt is holding a 
spin_lock(&xl_priv->xl_lock).   I know that you're not supposed to call shedule()
while holding a spin lock, but is it ok to call preempt_schedule()?

thanks,
dan carpenter

-- 
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