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Date: Tue, 18 Sep 2012 15:36:35 +0100
From: Greg KH <greg@kroah.com>
To: "Sebastian Gottschall (DD-WRT)" <s.gottschall@dd-wrt.com>
Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org
Subject: Re: XHCI Bug discovered in 3.6-RC6 (solution included)
Message-ID: <20120918143635.GF15432@kroah.com>
References: <5057C55D.2060402@dd-wrt.com>
 <5057C5AD.80609@dd-wrt.com>
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On Tue, Sep 18, 2012 at 02:51:57AM +0200, Sebastian Gottschall (DD-WRT) wrote:
> this following function is missing a important NULL check. if DMI is
> not available or not enabled in the kernel config (which is common
> in my case, since its a ARM Platform with XHCI support)
> the xhci-hcd driver will crash due nullpointer access since
> dmi_get_system_info returns always NULL if DMI support is not
> enabled.
> 
> static bool compliance_mode_recovery_timer_quirk_check(void)
> {
>     const char *dmi_product_name, *dmi_sys_vendor;
> 
>     dmi_product_name = dmi_get_system_info(DMI_PRODUCT_NAME);
>     dmi_sys_vendor = dmi_get_system_info(DMI_SYS_VENDOR);
> 
>     if (!(strstr(dmi_sys_vendor, "Hewlett-Packard")))
>         return false;
> 
>     if (strstr(dmi_product_name, "Z420") ||
>             strstr(dmi_product_name, "Z620") ||
>             strstr(dmi_product_name, "Z820"))
>         return true;
> 
>     return false;
> }
> 
> proposed patch: simply add
> 
>  if (!dmi_sys_vendor || !dmi_product_name)
>         return false;
> 
> even better. disable the whole quirk handling for this case if
> CONFIG_DMI is not set

Care to send a patch to fix this up?

thanks,

greg k-h