Date: Tue, 12 Dec 2017 20:57:01 -0500 (EST)
Message-Id: <20171212.205701.569779668163323943.davem@davemloft.net>
To: stephen@networkplumber.org
Cc: baijiaju1990@gmail.com, mlindner@marvell.com, shemminger@osdl.org,
        shemminger@linux-foundation.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [BUG] skge: a possible sleep-in-atomic bug in skge_remove
From: David Miller <davem@davemloft.net>
In-Reply-To: <20171212102240.4a09cf9a@xeon-e3>
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        <20171212.083445.2256119006373036925.davem@davemloft.net>
        <20171212102240.4a09cf9a@xeon-e3>
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From: Stephen Hemminger <stephen@networkplumber.org>
Date: Tue, 12 Dec 2017 10:22:40 -0800

> On Tue, 12 Dec 2017 08:34:45 -0500 (EST)
> David Miller <davem@davemloft.net> wrote:
> 
>> From: Jia-Ju Bai <baijiaju1990@gmail.com>
>> Date: Tue, 12 Dec 2017 16:38:12 +0800
>> 
>> > According to drivers/net/ethernet/marvell/skge.c, the driver may sleep
>> > under a spinlock.
>> > The function call path is:
>> > skge_remove (acquire the spinlock)
>> >   free_irq --> may sleep
>> > 
>> > I do not find a good way to fix it, so I only report.
>> > This possible bug is found by my static analysis tool (DSAC) and
>> > checked by my code review.  
>> 
>> This was added by:
>> 
>> commit a9e9fd7182332d0cf5f3e601df3e71dd431b70d7
>> Author: Stephen Hemminger <shemminger@vyatta.com>
>> Date:   Tue Sep 27 13:41:37 2011 -0400
>> 
>>     skge: handle irq better on single port card
>> 
>> I think the free_irq() can be moved below the unlock.
>> 
>> Stephen, please take a look.
> 
> The IRQ was being free twice.
> How did you see it, I really doubt any multi-port SKGE cards
> still exist.

He sees it by reading the code, please take a look at this
and move the free_irq() out of the spin locked section since
it can sleep.