From: Aaro Koskinen <aaro.koskinen@nsn.com>
Date: Tue, 22 Jul 2014 11:51:08 +0000 (+0300)
Subject: MIPS: OCTEON: make get_system_type() thread-safe
X-Git-Tag: v3.2.64~157
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a17245332e650651e3d70aa94013d806d61a40cb;p=pandora-kernel.git

MIPS: OCTEON: make get_system_type() thread-safe

commit 608308682addfdc7b8e2aee88f0e028331d88e4d upstream.

get_system_type() is not thread-safe on OCTEON. It uses static data,
also more dangerous issue is that it's calling cvmx_fuse_read_byte()
every time without any synchronization. Currently it's possible to get
processes stuck looping forever in kernel simply by launching multiple
readers of /proc/cpuinfo:

	(while true; do cat /proc/cpuinfo > /dev/null; done) &
	(while true; do cat /proc/cpuinfo > /dev/null; done) &
	...

Fix by initializing the system type string only once during the early
boot.

Signed-off-by: Aaro Koskinen <aaro.koskinen@nsn.com>
Reviewed-by: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: http://patchwork.linux-mips.org/patch/7437/
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

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