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From: Rusty Russell <rusty@rustcorp.com.au>
To: Alan Stern <stern@rowland.harvard.edu>
Subject: Re: Module parameters and __initdata
Date: Mon, 17 Jan 2011 09:49:44 +1030
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On Thu, 6 Jan 2011 08:46:59 am Alan Stern wrote:
> Is the proper use of "__initdata" with module parameters documented 
> anywhere?
> 
> I'm running into problems with drivers/usb/gadget/printer.c, which 
> includes code such as this:
> 
> 
> static ushort __initdata bcdDevice;
> module_param(bcdDevice, ushort, S_IRUGO);
> MODULE_PARM_DESC(bcdDevice, "USB Device version (BCD)");

You need to make perm 0.  You can't read it if it's freed after init!

Rusty.