From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <53CE59BE.104@imgtec.com> Date: Tue, 22 Jul 2014 13:31:58 +0100 From: Markos Chandras MIME-Version: 1.0 To: Aaro Koskinen , Ralf Baechle , David Daney , , CC: Subject: Re: [PATCH] MIPS: OCTEON: make get_system_type() thread-safe References: <1406029868-6210-1-git-send-email-aaro.koskinen@nsn.com> In-Reply-To: <1406029868-6210-1-git-send-email-aaro.koskinen@nsn.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: On 07/22/2014 12:51 PM, Aaro Koskinen wrote: > 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 > Cc: stable@vger.kernel.org > --- > arch/mips/cavium-octeon/setup.c | 18 +++++++++++++----- > 1 file changed, 13 insertions(+), 5 deletions(-) > It looks reasonable to me. Reviewed-by: Markos Chandras -- markos