Re: [PATCH] hwmon: coretemp: fix oops on cpu unplug

[Kirill A. Shutemov]

On Tue, May 01, 2012 at 08:20:14AM -0700, Guenter Roeck wrote:
> On Mon, Apr 30, 2012 at 09:18:01AM -0400, Kirill A. Shutemov wrote:
> > From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
> > 
> > coretemp tries to access core_data array beyond bounds on cpu unplug if
> > core id of the cpu if more than NUM_REAL_CORES-1.
> > 
> [ ... ]
> > 
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> 
> Looking at it again, you were right. Adding the check to get_core_online()
> doesn't really help as the platform device is per CPU, not per core.
> 
> Applied. I'll submit a separate patch to increase NUM_REAL_CORES.

Actually, the problem is bigger.

Documentation/cputopology.txt:
====
2) /sys/devices/system/cpu/cpuX/topology/core_id:

        the CPU core ID of cpuX. Typically it is the hardware platform's
        identifier (rather than the kernel's).  The actual value is
        architecture and platform dependent.
====

We should not use core id as an index in an array since it's an arbitrary
number (from kernel POV).

-- 
 Kirill A. Shutemov
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