Re: [ 06/37] x86-32: Fix invalid stack address while in softirq

[Greg Kroah-Hartman]

On Tue, Dec 04, 2012 at 11:42:58AM -0200, Herton Ronaldo Krzesinski wrote:
> On Fri, Nov 30, 2012 at 10:45:53AM -0800, Greg Kroah-Hartman wrote:
> > 3.0-stable review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > From: Robert Richter <robert.richter@xxxxxxx>
> > 
> > commit 1022623842cb72ee4d0dbf02f6937f38c92c3f41 upstream.
> > 
> > In 32 bit the stack address provided by kernel_stack_pointer() may
> > point to an invalid range causing NULL pointer access or page faults
> > while in NMI (see trace below). This happens if called in softirq
> > context and if the stack is empty. The address at &regs->sp is then
> > out of range.
> > 
> > Fixing this by checking if regs and &regs->sp are in the same stack
> > context. Otherwise return the previous stack pointer stored in struct
> > thread_info. If that address is invalid too, return address of regs.
> > 
> [...]
> 
> Hi, this makes build fail with oprofile on i386 on 3.0.54:
> ERROR: "kernel_stack_pointer" [arch/x86/oprofile/oprofile.ko] undefined!

Now fixed with 3.0.55.

thanks,

greg k-h
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