linux-kernel - Re: sleeping function called from invalid context

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Date:	Wed, 11 May 2011 14:13:21 +0530
From:	Amit Virdi <amit.virdi@...com>
To:	Alan Cox <alan@...ux.intel.com>
Cc:	"linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
	"samuel@...tiz.org" <samuel@...tiz.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Shiraz HASHIM <shiraz.hashim@...com>,
	Armando VISCONTI <armando.visconti@...com>,
	Viresh KUMAR <viresh.kumar@...com>
Subject: Re: sleeping function called from invalid context

Hey Alan,

On 5/10/2011 3:02 PM, Alan Cox wrote:
>> On analysis, I found that this is due to the change introduced in
>> tty_ioctl.c where the termios mutex is taken to protect against
>> parallel throttle/unthrottle. Probably IrCOMM stack code wasn't
>> tested before merging this patch.
>>
>> Please suggest what should be done with the IrCOMM protocol stack
>> code to resolve this problem?
>
> It looks like the comments are wrong
>
>          /*
>           * Just give it over to the line discipline. There is no need to
>           * involve the flip buffers, since we are not running in an
>          interrupt
>           * handler
>           */
>
>
> appears to be completely untrue
>
> I suspect it just needs to use the tty_flip_buffer functions properly
> instead of trying to do clever shortcuts
>
>
> 	tty_insert_flip_string(self->tty, skb->data, skb->len);
> 	tty_flip_buffer_push(self->tty);
>
> .
>

I incorporated the change suggested by you and tested the stack again. 
It is working perfectly fine - no stack trace is printed now. I'll be 
sending the patch soon.

Thanks n Regards
Amit Virdi
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