/* * MOXA ART SoCs watchdog driver. * * Copyright (C) 2013 Jonas Jensen * * Jonas Jensen * * This file is licensed under the terms of the GNU General Public * License version 2. This program is licensed "as is" without any * warranty of any kind, whether express or implied. */ #include #include #include #include #include #include #include #include #define REG_COUNT 0x4 #define REG_MODE 0x8 #define REG_ENABLE 0xC struct moxart_wdt_dev { struct watchdog_device dev; void __iomem *base; unsigned int clock_frequency; }; static int heartbeat; static int moxart_wdt_restart(struct watchdog_device *wdt_dev, unsigned long action, void *data) { struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); writel(1, moxart_wdt->base + REG_COUNT); writel(0x5ab9, moxart_wdt->base + REG_MODE); writel(0x03, moxart_wdt->base + REG_ENABLE); return 0; } static int moxart_wdt_stop(struct watchdog_device *wdt_dev) { struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); writel(0, moxart_wdt->base + REG_ENABLE); return 0; } static int moxart_wdt_start(struct watchdog_device *wdt_dev) { struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); writel(moxart_wdt->clock_frequency * wdt_dev->timeout, moxart_wdt->base + REG_COUNT); writel(0x5ab9, moxart_wdt->base + REG_MODE); writel(0x03, moxart_wdt->base + REG_ENABLE); return 0; } static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev, unsigned int timeout) { wdt_dev->timeout = timeout; return 0; } static const struct watchdog_info moxart_wdt_info = { .identity = "moxart-wdt", .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, }; static const struct watchdog_ops moxart_wdt_ops = { .owner = THIS_MODULE, .start = moxart_wdt_start, .stop = moxart_wdt_stop, .set_timeout = moxart_wdt_set_timeout, .restart = moxart_wdt_restart, }; static int moxart_wdt_probe(struct platform_device *pdev) { struct moxart_wdt_dev *moxart_wdt; struct device *dev = &pdev->dev; struct device_node *node = dev->of_node; struct resource *res; struct clk *clk; int err; unsigned int max_timeout; bool nowayout = WATCHDOG_NOWAYOUT; moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL); if (!moxart_wdt) return -ENOMEM; platform_set_drvdata(pdev, moxart_wdt); res = platform_get_resource(pdev, IORESOURCE_MEM, 0); moxart_wdt->base = devm_ioremap_resource(dev, res); if (IS_ERR(moxart_wdt->base)) return PTR_ERR(moxart_wdt->base); clk = of_clk_get(node, 0); if (IS_ERR(clk)) { pr_err("%s: of_clk_get failed\n", __func__); return PTR_ERR(clk); } moxart_wdt->clock_frequency = clk_get_rate(clk); if (moxart_wdt->clock_frequency == 0) { pr_err("%s: incorrect clock frequency\n", __func__); return -EINVAL; } max_timeout = UINT_MAX / moxart_wdt->clock_frequency; moxart_wdt->dev.info = &moxart_wdt_info; moxart_wdt->dev.ops = &moxart_wdt_ops; moxart_wdt->dev.timeout = max_timeout; moxart_wdt->dev.min_timeout = 1; moxart_wdt->dev.max_timeout = max_timeout; moxart_wdt->dev.parent = dev; watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev); watchdog_set_nowayout(&moxart_wdt->dev, nowayout); watchdog_set_restart_priority(&moxart_wdt->dev, 128); watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt); err = watchdog_register_device(&moxart_wdt->dev); if (err) return err; dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n", moxart_wdt->dev.timeout, nowayout); return 0; } static int moxart_wdt_remove(struct platform_device *pdev) { struct moxart_wdt_dev *moxart_wdt = platform_get_drvdata(pdev); moxart_wdt_stop(&moxart_wdt->dev); return 0; } static const struct of_device_id moxart_watchdog_match[] = { { .compatible = "moxa,moxart-watchdog" }, { }, }; MODULE_DEVICE_TABLE(of, moxart_watchdog_match); static struct platform_driver moxart_wdt_driver = { .probe = moxart_wdt_probe, .remove = moxart_wdt_remove, .driver = { .name = "moxart-watchdog", .of_match_table = moxart_watchdog_match, }, }; module_platform_driver(moxart_wdt_driver); module_param(heartbeat, int, 0); MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds"); MODULE_DESCRIPTION("MOXART watchdog driver"); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Jonas Jensen "); lue='10'>10space:mode:
authorDouglas Miller <dougmill@linux.vnet.ibm.com>2017-01-28 06:42:20 -0600
committerTejun Heo <tj@kernel.org>2017-01-28 07:49:42 -0500
commit966d2b04e070bc040319aaebfec09e0144dc3341 (patch)
tree4b96156e3d1dd4dfd6039b7c219c9dc4616da52d /tools/perf/pmu-events/arch/x86/ivybridge/virtual-memory.json
parent1b1bc42c1692e9b62756323c675a44cb1a1f9dbd (diff)
percpu-refcount: fix reference leak during percpu-atomic transition
percpu_ref_tryget() and percpu_ref_tryget_live() should return "true" IFF they acquire a reference. But the return value from atomic_long_inc_not_zero() is a long and may have high bits set, e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines is bool so the reference may actually be acquired but the routines return "false" which results in a reference leak since the caller assumes it does not need to do a corresponding percpu_ref_put(). This was seen when performing CPU hotplug during I/O, as hangs in blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start) raced with percpu_ref_tryget (blk_mq_timeout_work). Sample stack trace: __switch_to+0x2c0/0x450 __schedule+0x2f8/0x970 schedule+0x48/0xc0 blk_mq_freeze_queue_wait+0x94/0x120 blk_mq_queue_reinit_work+0xb8/0x180 blk_mq_queue_reinit_prepare+0x84/0xa0 cpuhp_invoke_callback+0x17c/0x600 cpuhp_up_callbacks+0x58/0x150 _cpu_up+0xf0/0x1c0 do_cpu_up+0x120/0x150 cpu_subsys_online+0x64/0xe0 device_online+0xb4/0x120 online_store+0xb4/0xc0 dev_attr_store+0x68/0xa0 sysfs_kf_write+0x80/0xb0 kernfs_fop_write+0x17c/0x250 __vfs_write+0x6c/0x1e0 vfs_write+0xd0/0x270 SyS_write+0x6c/0x110 system_call+0x38/0xe0 Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS, and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests. However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0 and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set. The fix is to make the tryget routines use an actual boolean internally instead of the atomic long result truncated to a int. Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751 Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints") Cc: stable@vger.kernel.org # v3.18+
Diffstat (limited to 'tools/perf/pmu-events/arch/x86/ivybridge/virtual-memory.json')