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From: Guenter Roeck <guenter.roeck@ericsson.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	Jean Delvare <khali@linux-fr.org>,
	"lm-sensors@lm-sensors.org" <lm-sensors@lm-sensors.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [lm-sensors] [PATCH] hwmon: coretemp: fix oops on cpu unplug
Date: Tue, 01 May 2012 21:25:12 +0000	[thread overview]
Message-ID: <20120501212512.GA4340@ericsson.com> (raw)
In-Reply-To: <20120501210041.GA10629@otc-wbsnb-06>

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" <kirill.shutemov@linux.intel.com>
> > > 
> > > 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@linux.intel.com>
> > 
> > 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

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WARNING: multiple messages have this Message-ID (diff)
From: Guenter Roeck <guenter.roeck@ericsson.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	Jean Delvare <khali@linux-fr.org>,
	"lm-sensors@lm-sensors.org" <lm-sensors@lm-sensors.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] hwmon: coretemp: fix oops on cpu unplug
Date: Tue, 1 May 2012 14:25:12 -0700	[thread overview]
Message-ID: <20120501212512.GA4340@ericsson.com> (raw)
In-Reply-To: <20120501210041.GA10629@otc-wbsnb-06>

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" <kirill.shutemov@linux.intel.com>
> > > 
> > > 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@linux.intel.com>
> > 
> > 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

  reply	other threads:[~2012-05-01 21:25 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-30 13:18 [lm-sensors] [PATCH] hwmon: coretemp: fix oops on cpu unplug Kirill A. Shutemov
2012-04-30 13:18 ` Kirill A. Shutemov
2012-04-30 15:28 ` [lm-sensors] " Guenter Roeck
2012-04-30 15:28   ` Guenter Roeck
2012-04-30 16:19   ` [lm-sensors] " Kirill A. Shutemov
2012-04-30 16:19     ` Kirill A. Shutemov
2012-04-30 16:59     ` [lm-sensors] " Guenter Roeck
2012-04-30 16:59       ` Guenter Roeck
2012-05-01 15:20 ` [lm-sensors] " Guenter Roeck
2012-05-01 15:20   ` Guenter Roeck
2012-05-01 21:00   ` [lm-sensors] " Kirill A. Shutemov
2012-05-01 21:00     ` Kirill A. Shutemov
2012-05-01 21:25     ` Guenter Roeck [this message]
2012-05-01 21:25       ` Guenter Roeck
2012-05-02 15:10       ` [lm-sensors] [PATCH] hwmon: coretemp: use list instead of fixed size array for temp data Kirill A. Shutemov
2012-05-02 15:10         ` Kirill A. Shutemov
2012-05-03  5:29         ` [lm-sensors] " R, Durgadoss
2012-05-03  5:29           ` R, Durgadoss
2012-05-03 10:04           ` Kirill A. Shutemov
2012-05-03 10:04             ` Kirill A. Shutemov
2012-05-03 11:18         ` [lm-sensors] [PATCH, v2] hwmon: coretemp: use list instead of fixed size array for temp Kirill A. Shutemov
2012-05-03 11:18           ` [PATCH, v2] hwmon: coretemp: use list instead of fixed size array for temp data Kirill A. Shutemov
2012-05-04  5:41           ` [lm-sensors] [PATCH, v2] hwmon: coretemp: use list instead of fixed size array for temp Guenter Roeck
2012-05-04  5:41             ` [PATCH, v2] hwmon: coretemp: use list instead of fixed size array for temp data Guenter Roeck
2012-05-04  6:46             ` [lm-sensors] [PATCH, v2] hwmon: coretemp: use list instead of fixed size array for temp Kirill A. Shutemov
2012-05-04  6:46               ` [PATCH, v2] hwmon: coretemp: use list instead of fixed size array for temp data Kirill A. Shutemov
2012-05-04 13:34               ` [lm-sensors] [PATCH, v2] hwmon: coretemp: use list instead of fixed size array for temp Guenter Roeck
2012-05-04 13:34                 ` [PATCH, v2] hwmon: coretemp: use list instead of fixed size array for temp data Guenter Roeck
2012-05-04 13:42                 ` [lm-sensors] [PATCH, v2] hwmon: coretemp: use list instead of fixed size array for temp Kirill A. Shutemov
2012-05-04 13:42                   ` [PATCH, v2] hwmon: coretemp: use list instead of fixed size array for temp data Kirill A. Shutemov
2015-07-15 16:04         ` [lm-sensors] [PATCH] " Lukasz Odzioba
2015-07-15 16:04           ` Lukasz Odzioba
2015-07-15 21:07           ` [lm-sensors] " Jean Delvare
2015-07-15 21:07             ` Jean Delvare
2015-07-16 13:17             ` [lm-sensors] " Odzioba, Lukasz
2015-07-16 13:17               ` Odzioba, Lukasz
2015-07-17 16:55               ` [lm-sensors] " Guenter Roeck
2015-07-17 16:55                 ` Guenter Roeck
2015-07-17 17:28                 ` [lm-sensors] " Odzioba, Lukasz
2015-07-17 17:28                   ` Odzioba, Lukasz
2015-07-17 18:01                   ` [lm-sensors] " Guenter Roeck
2015-07-17 18:01                     ` Guenter Roeck
2015-07-17 19:23                     ` [lm-sensors] " Odzioba, Lukasz
2015-07-17 19:23                       ` Odzioba, Lukasz
2015-07-17 21:33                       ` [lm-sensors] " Jean Delvare
2015-07-17 21:33                         ` Jean Delvare
2015-07-17 19:11                   ` [lm-sensors] " Jean Delvare
2015-07-17 19:11                     ` Jean Delvare
2015-07-17 19:36                     ` [lm-sensors] " Guenter Roeck
2015-07-17 19:36                       ` Guenter Roeck
2015-07-17 21:25                       ` [lm-sensors] " Jean Delvare
2015-07-17 21:25                         ` Jean Delvare

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