Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754449Ab2EAV1e (ORCPT ); Tue, 1 May 2012 17:27:34 -0400 Received: from imr3.ericy.com ([198.24.6.13]:38505 "EHLO imr3.ericy.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753825Ab2EAV1d (ORCPT ); Tue, 1 May 2012 17:27:33 -0400 Date: Tue, 1 May 2012 14:25:12 -0700 From: Guenter Roeck To: "Kirill A. Shutemov" CC: Fenghua Yu , Andi Kleen , Jean Delvare , "lm-sensors@lm-sensors.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] hwmon: coretemp: fix oops on cpu unplug Message-ID: <20120501212512.GA4340@ericsson.com> References: <1335791881-1560-1-git-send-email-kirill.shutemov@linux.intel.com> <20120501152014.GA2629@ericsson.com> <20120501210041.GA10629@otc-wbsnb-06> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20120501210041.GA10629@otc-wbsnb-06> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1561 Lines: 41 On Tue, May 01, 2012 at 05:00:41PM -0400, Kirill A. Shutemov wrote: > 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" > > > > > > 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 > > > > 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). > Yes, we know we'll need a better fix going forward. Using a fixed size array is bad, no matter what context. Thanks, Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/