percpu: fix first chunk match in per_cpu_ptr_to_phys()
authorTejun Heo <tj@kernel.org>
Fri, 18 Jun 2010 09:44:31 +0000 (11:44 +0200)
committerTejun Heo <tj@kernel.org>
Fri, 18 Jun 2010 13:07:23 +0000 (15:07 +0200)
commit9983b6f0cf8263e51bcf4c8a9dc0c1ef175b3c60
treea9b7bacbdf8e30b931c2ebd849104b04b157d48d
parenta92d3ff9e5dbd958d8008a3e7a573e988e370ca3
percpu: fix first chunk match in per_cpu_ptr_to_phys()

per_cpu_ptr_to_phys() determines whether the passed in @addr belongs
to the first_chunk or not by just matching the address against the
address range of the base unit (unit0, used by cpu0).  When an adress
from another cpu was passed in, it will always determine that the
address doesn't belong to the first chunk even when it does.  This
makes the function return a bogus physical address which may lead to
crash.

This problem was discovered by Cliff Wickman while investigating a
crash during kdump on a SGI UV system.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Cliff Wickman <cpw@sgi.com>
Tested-by: Cliff Wickman <cpw@sgi.com>
Cc: stable@kernel.org
mm/percpu.c