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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
pwm-lpss-pci.c 
/*
 * Intel Low Power Subsystem PWM controller PCI driver
 *
 * Copyright (C) 2014, Intel Corporation
 *
 * Derived from the original pwm-lpss.c
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/pm_runtime.h>

#include "pwm-lpss.h"

static int pwm_lpss_probe_pci(struct pci_dev *pdev,
			      const struct pci_device_id *id)
{
	const struct pwm_lpss_boardinfo *info;
	struct pwm_lpss_chip *lpwm;
	int err;

	err = pcim_enable_device(pdev);
	if (err < 0)
		return err;

	info = (struct pwm_lpss_boardinfo *)id->driver_data;
	lpwm = pwm_lpss_probe(&pdev->dev, &pdev->resource[0], info);
	if (IS_ERR(lpwm))
		return PTR_ERR(lpwm);

	pci_set_drvdata(pdev, lpwm);

	pm_runtime_put(&pdev->dev);
	pm_runtime_allow(&pdev->dev);

	return 0;
}

static void pwm_lpss_remove_pci(struct pci_dev *pdev)
{
	struct pwm_lpss_chip *lpwm = pci_get_drvdata(pdev);

	pm_runtime_forbid(&pdev->dev);
	pm_runtime_get_sync(&pdev->dev);

	pwm_lpss_remove(lpwm);
}

#ifdef CONFIG_PM
static int pwm_lpss_runtime_suspend_pci(struct device *dev)
{
	/*
	 * The PCI core will handle transition to D3 automatically. We only
	 * need to provide runtime PM hooks for that to happen.
	 */
	return 0;
}

static int pwm_lpss_runtime_resume_pci(struct device *dev)
{
	return 0;
}
#endif

static const struct dev_pm_ops pwm_lpss_pci_pm = {
	SET_RUNTIME_PM_OPS(pwm_lpss_runtime_suspend_pci,
			   pwm_lpss_runtime_resume_pci, NULL)
};

static const struct pci_device_id pwm_lpss_pci_ids[] = {
	{ PCI_VDEVICE(INTEL, 0x0ac8), (unsigned long)&pwm_lpss_bxt_info},
	{ PCI_VDEVICE(INTEL, 0x0f08), (unsigned long)&pwm_lpss_byt_info},
	{ PCI_VDEVICE(INTEL, 0x0f09), (unsigned long)&pwm_lpss_byt_info},
	{ PCI_VDEVICE(INTEL, 0x11a5), (unsigned long)&pwm_lpss_bxt_info},
	{ PCI_VDEVICE(INTEL, 0x1ac8), (unsigned long)&pwm_lpss_bxt_info},
	{ PCI_VDEVICE(INTEL, 0x2288), (unsigned long)&pwm_lpss_bsw_info},
	{ PCI_VDEVICE(INTEL, 0x2289), (unsigned long)&pwm_lpss_bsw_info},
	{ PCI_VDEVICE(INTEL, 0x5ac8), (unsigned long)&pwm_lpss_bxt_info},
	{ },
};
MODULE_DEVICE_TABLE(pci, pwm_lpss_pci_ids);

static struct pci_driver pwm_lpss_driver_pci = {
	.name = "pwm-lpss",
	.id_table = pwm_lpss_pci_ids,
	.probe = pwm_lpss_probe_pci,
	.remove = pwm_lpss_remove_pci,
	.driver = {
		.pm = &pwm_lpss_pci_pm,
	},
};
module_pci_driver(pwm_lpss_driver_pci);

MODULE_DESCRIPTION("PWM PCI driver for Intel LPSS");
MODULE_LICENSE("GPL v2");
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