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Revision 0933840acf7b65d6d30a5b6089d882afea57aca3 authored by Jiri Olsa on 20 October 2016, 11:10:11 UTC, committed by Ingo Molnar on 28 October 2016, 09:06:25 UTC 
perf/core: Protect PMU device removal with a 'pmu_bus_running' check, to fix CONFIG_DEBUG_TEST_DRIVER_REMOVE=y kernel panic
 
CAI Qian reported a crash in the PMU uncore device removal code,
enabled by the CONFIG_DEBUG_TEST_DRIVER_REMOVE=y option:

  https://marc.info/?l=linux-kernel&m=147688837328451

The reason for the crash is that perf_pmu_unregister() tries to remove
a PMU device which is not added at this point. We add PMU devices
only after pmu_bus is registered, which happens in the
perf_event_sysfs_init() call and sets the 'pmu_bus_running' flag.

The fix is to get the 'pmu_bus_running' flag state at the point
the PMU is taken out of the PMU list and remove the device
later only if it's set.

Reported-by: CAI Qian <caiqian@redhat.com>
Tested-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161020111011.GA13361@krava
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 parent 889882b
Raw File
rtc-ps3.c 
/*
 * PS3 RTC Driver
 *
 * Copyright 2009 Sony Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.
 * If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>

#include <asm/lv1call.h>
#include <asm/ps3.h>


static u64 read_rtc(void)
{
	int result;
	u64 rtc_val;
	u64 tb_val;

	result = lv1_get_rtc(&rtc_val, &tb_val);
	BUG_ON(result);

	return rtc_val;
}

static int ps3_get_time(struct device *dev, struct rtc_time *tm)
{
	rtc_time_to_tm(read_rtc() + ps3_os_area_get_rtc_diff(), tm);
	return rtc_valid_tm(tm);
}

static int ps3_set_time(struct device *dev, struct rtc_time *tm)
{
	unsigned long now;

	rtc_tm_to_time(tm, &now);
	ps3_os_area_set_rtc_diff(now - read_rtc());
	return 0;
}

static const struct rtc_class_ops ps3_rtc_ops = {
	.read_time = ps3_get_time,
	.set_time = ps3_set_time,
};

static int __init ps3_rtc_probe(struct platform_device *dev)
{
	struct rtc_device *rtc;

	rtc = devm_rtc_device_register(&dev->dev, "rtc-ps3", &ps3_rtc_ops,
				  THIS_MODULE);
	if (IS_ERR(rtc))
		return PTR_ERR(rtc);

	platform_set_drvdata(dev, rtc);
	return 0;
}

static struct platform_driver ps3_rtc_driver = {
	.driver = {
		.name = "rtc-ps3",
	},
};

module_platform_driver_probe(ps3_rtc_driver, ps3_rtc_probe);

MODULE_AUTHOR("Sony Corporation");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ps3 RTC driver");
MODULE_ALIAS("platform:rtc-ps3");
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