Re: The reason of panic while 'cat /proc/ioports' [Re: SS_CAP_STATIC_MAP and...]

On Fri, Mar 14, 2003 at 05:06:35PM +0300, Dmitry Antipov wrote:
>  Thanks to all for explanations and interesting discussion. Yes, I'm 
> working with 2.4,
> and I hope we will have more  consistent approach  in 2.5 :-).
> 
>  The reason for kernel panic at 'cat /proc/ioports' looks simple. Each 
> resource has a name:
> 
>  struct resource {
>         const char *name;
>         ...
> };
> 
> This name is not copied in __request_region(), and 'name' points to some 
> string
> constant in a module space. This pointer becomes invalid after module 
> unloading, so
> dereferencing it in do_resource_list() causes 'Unable to handle....' bug.

Correct.  The rule is that resources claimed by a module should be released
before that module is unloaded.

Something isn't doing that, and that's the problem - it isn't that we
aren't copying the string into the resource structure.

-- 
Russell King ([email protected])                The developer of ARM Linux
             http://www.arm.linux.org.uk/personal/aboutme.html



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