/* * Retu watchdog driver * * Copyright (C) 2004, 2005 Nokia Corporation * * Based on code written by Amit Kucheria and Michael Buesch. * Rewritten by Aaro Koskinen. * * This file is subject to the terms and conditions of the GNU General * Public License. See the file "COPYING" in the main directory of this * archive for more details. * * 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. */ #include #include #include #include #include #include #include #include /* Watchdog timer values in seconds */ #define RETU_WDT_MAX_TIMER 63 struct retu_wdt_dev { struct retu_dev *rdev; struct device *dev; struct delayed_work ping_work; }; /* * Since Retu watchdog cannot be disabled in hardware, we must kick it * with a timer until userspace watchdog software takes over. If * CONFIG_WATCHDOG_NOWAYOUT is set, we never start the feeding. */ static void retu_wdt_ping_enable(struct retu_wdt_dev *wdev) { retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER); schedule_delayed_work(&wdev->ping_work, round_jiffies_relative(RETU_WDT_MAX_TIMER * HZ / 2)); } static void retu_wdt_ping_disable(struct retu_wdt_dev *wdev) { retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER); cancel_delayed_work_sync(&wdev->ping_work); } static void retu_wdt_ping_work(struct work_struct *work) { struct retu_wdt_dev *wdev = container_of(to_delayed_work(work), struct retu_wdt_dev, ping_work); retu_wdt_ping_enable(wdev); } static int retu_wdt_start(struct watchdog_device *wdog) { struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog); retu_wdt_ping_disable(wdev); return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout); } static int retu_wdt_stop(struct watchdog_device *wdog) { struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog); retu_wdt_ping_enable(wdev); return 0; } static int retu_wdt_ping(struct watchdog_device *wdog) { struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog); return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout); } static int retu_wdt_set_timeout(struct watchdog_device *wdog, unsigned int timeout) { struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog); wdog->timeout = timeout; return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout); } static const struct watchdog_info retu_wdt_info = { .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, .identity = "Retu watchdog", }; static const struct watchdog_ops retu_wdt_ops = { .owner = THIS_MODULE, .start = retu_wdt_start, .stop = retu_wdt_stop, .ping = retu_wdt_ping, .set_timeout = retu_wdt_set_timeout, }; static int retu_wdt_probe(struct platform_device *pdev) { struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent); bool nowayout = WATCHDOG_NOWAYOUT; struct watchdog_device *retu_wdt; struct retu_wdt_dev *wdev; int ret; retu_wdt = devm_kzalloc(&pdev->dev, sizeof(*retu_wdt), GFP_KERNEL); if (!retu_wdt) return -ENOMEM; wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL); if (!wdev) return -ENOMEM; retu_wdt->info = &retu_wdt_info; retu_wdt->ops = &retu_wdt_ops; retu_wdt->timeout = RETU_WDT_MAX_TIMER; retu_wdt->min_timeout = 0; retu_wdt->max_timeout = RETU_WDT_MAX_TIMER; retu_wdt->parent = &pdev->dev; watchdog_set_drvdata(retu_wdt, wdev); watchdog_set_nowayout(retu_wdt, nowayout); wdev->rdev = rdev; wdev->dev = &pdev->dev; INIT_DELAYED_WORK(&wdev->ping_work, retu_wdt_ping_work); ret = watchdog_register_device(retu_wdt); if (ret < 0) return ret; if (nowayout) retu_wdt_ping(retu_wdt); else retu_wdt_ping_enable(wdev); platform_set_drvdata(pdev, retu_wdt); return 0; } static int retu_wdt_remove(struct platform_device *pdev) { struct watchdog_device *wdog = platform_get_drvdata(pdev); struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog); watchdog_unregister_device(wdog); cancel_delayed_work_sync(&wdev->ping_work); return 0; } static struct platform_driver retu_wdt_driver = { .probe = retu_wdt_probe, .remove = retu_wdt_remove, .driver = { .name = "retu-wdt", }, }; module_platform_driver(retu_wdt_driver); MODULE_ALIAS("platform:retu-wdt"); MODULE_DESCRIPTION("Retu watchdog"); MODULE_AUTHOR("Amit Kucheria"); MODULE_AUTHOR("Aaro Koskinen "); MODULE_LICENSE("GPL"); committerLinus Torvalds <torvalds@linux-foundation.org>2017-01-29 13:50:06 -0800 commit39cb2c9a316e77f6dfba96c543e55b6672d5a37e (patch) tree98fe974ee4e20121253de7f61fc8d01bdb3821c1 /sound/oss/uart401.c parent2c5d9555d6d937966d79d4c6529a5f7b9206e405 (diff)
drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()
I've seen this trigger twice now, where the i915_gem_object_to_ggtt() call in intel_unpin_fb_obj() returns NULL, resulting in an oops immediately afterwards as the (inlined) call to i915_vma_unpin_fence() tries to dereference it. It seems to be some race condition where the object is going away at shutdown time, since both times happened when shutting down the X server. The call chains were different: - VT ioctl(KDSETMODE, KD_TEXT): intel_cleanup_plane_fb+0x5b/0xa0 [i915] drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper] intel_atomic_commit_tail+0x749/0xfe0 [i915] intel_atomic_commit+0x3cb/0x4f0 [i915] drm_atomic_commit+0x4b/0x50 [drm] restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper] drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper] drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper] intel_fbdev_set_par+0x18/0x70 [i915] fb_set_var+0x236/0x460 fbcon_blank+0x30f/0x350 do_unblank_screen+0xd2/0x1a0 vt_ioctl+0x507/0x12a0 tty_ioctl+0x355/0xc30 do_vfs_ioctl+0xa3/0x5e0 SyS_ioctl+0x79/0x90 entry_SYSCALL_64_fastpath+0x13/0x94 - i915 unpin_work workqueue: intel_unpin_work_fn+0x58/0x140 [i915] process_one_work+0x1f1/0x480 worker_thread+0x48/0x4d0 kthread+0x101/0x140 and this patch purely papers over the issue by adding a NULL pointer check and a WARN_ON_ONCE() to avoid the oops that would then generally make the machine unresponsive. Other callers of i915_gem_object_to_ggtt() seem to also check for the returned pointer being NULL and warn about it, so this clearly has happened before in other places. [ Reported it originally to the i915 developers on Jan 8, applying the ugly workaround on my own now after triggering the problem for the second time with no feedback. This is likely to be the same bug reported as https://bugs.freedesktop.org/show_bug.cgi?id=98829 https://bugs.freedesktop.org/show_bug.cgi?id=99134 which has a patch for the underlying problem, but it hasn't gotten to me, so I'm applying the workaround. ] Cc: Daniel Vetter <daniel.vetter@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Imre Deak <imre.deak@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'sound/oss/uart401.c')