Re: [PATCH 1/1] tpm: fix cause of SMP stack traces

[Chris Wright <chrisw@osdl.org>]

* Kylene Hall (kjhall@us.ibm.com) wrote:
> There were misplaced spinlock acquires and releases in the probe, open, 
> close and release paths which were causing might_sleep and schedule while 
> atomic error messages accompanied by stack traces when the kernel was 
> compiled with SMP support. Bug reported by Reben Jenster 
> <ruben@hotheads.de>
> 
> Signed-off-by: Kylene Hall <kjhall@us.ibm.com>
> ---
> diff -uprN linux-2.6.10/drivers/char/tpm/tpm.c linux-2.6.10-tpm/drivers/char/tpm/tpm.c
> --- linux-2.6.10/drivers/char/tpm/tpm.c	2005-01-18 16:42:17.000000000 -0600
> +++ linux-2.6.10-tpm/drivers/char/tpm/tpm.c	2005-01-18 12:52:53.000000000 -0600
> @@ -373,8 +372,9 @@ int tpm_open(struct inode *inode, struct
>  {
>  	int rc = 0, minor = iminor(inode);
>  	struct tpm_chip *chip = NULL, *pos;
> +	unsigned long flags;
>  
> -	spin_lock(&driver_lock);
> +	spin_lock_irqsave(&driver_lock, flags);

Hmm, unless I'm missing something, this is only worse (for might sleep
warnings).  Now you've disabled irq's too.

thanks,
-chris
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