/* * IndyDog 0.3 A Hardware Watchdog Device for SGI IP22 * * (c) Copyright 2002 Guido Guenther , * All Rights Reserved. * * 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; either version * 2 of the License, or (at your option) any later version. * * based on softdog.c by Alan Cox */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include static unsigned long indydog_alive; static DEFINE_SPINLOCK(indydog_lock); #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); static void indydog_start(void) { spin_lock(&indydog_lock); sgimc->cpuctrl0 |= SGIMC_CCTRL0_WDOG; spin_unlock(&indydog_lock); } static void indydog_stop(void) { spin_lock(&indydog_lock); sgimc->cpuctrl0 &= ~SGIMC_CCTRL0_WDOG; spin_unlock(&indydog_lock); pr_info("Stopped watchdog timer\n"); } static void indydog_ping(void) { sgimc->watchdogt = 0; } /* * Allow only one person to hold it open */ static int indydog_open(struct inode *inode, struct file *file) { if (test_and_set_bit(0, &indydog_alive)) return -EBUSY; if (nowayout) __module_get(THIS_MODULE); /* Activate timer */ indydog_start(); indydog_ping(); pr_info("Started watchdog timer\n"); return nonseekable_open(inode, file); } static int indydog_release(struct inode *inode, struct file *file) { /* Shut off the timer. * Lock it in if it's a module and we defined ...NOWAYOUT */ if (!nowayout) indydog_stop(); /* Turn the WDT off */ clear_bit(0, &indydog_alive); return 0; } static ssize_t indydog_write(struct file *file, const char *data, size_t len, loff_t *ppos) { /* Refresh the timer. */ if (len) indydog_ping(); return len; } static long indydog_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int options, retval = -EINVAL; static const struct watchdog_info ident = { .options = WDIOF_KEEPALIVEPING, .firmware_version = 0, .identity = "Hardware Watchdog for SGI IP22", }; switch (cmd) { case WDIOC_GETSUPPORT: if (copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident))) return -EFAULT; return 0; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(0, (int *)arg); case WDIOC_SETOPTIONS: { if (get_user(options, (int *)arg)) return -EFAULT; if (options & WDIOS_DISABLECARD) { indydog_stop(); retval = 0; } if (options & WDIOS_ENABLECARD) { indydog_start(); retval = 0; } return retval; } case WDIOC_KEEPALIVE: indydog_ping(); return 0; case WDIOC_GETTIMEOUT: return put_user(WATCHDOG_TIMEOUT, (int *)arg); default: return -ENOTTY; } } static int indydog_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if (code == SYS_DOWN || code == SYS_HALT) indydog_stop(); /* Turn the WDT off */ return NOTIFY_DONE; } static const struct file_operations indydog_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = indydog_write, .unlocked_ioctl = indydog_ioctl, .open = indydog_open, .release = indydog_release, }; static struct miscdevice indydog_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &indydog_fops, }; static struct notifier_block indydog_notifier = { .notifier_call = indydog_notify_sys, }; static int __init watchdog_init(void) { int ret; ret = register_reboot_notifier(&indydog_notifier); if (ret) { pr_err("cannot register reboot notifier (err=%d)\n", ret); return ret; } ret = misc_register(&indydog_miscdev); if (ret) { pr_err("cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, ret); unregister_reboot_notifier(&indydog_notifier); return ret; } pr_info("Hardware Watchdog Timer for SGI IP22: 0.3\n"); return 0; } static void __exit watchdog_exit(void) { misc_deregister(&indydog_miscdev); unregister_reboot_notifier(&indydog_notifier); } module_init(watchdog_init); module_exit(watchdog_exit); MODULE_AUTHOR("Guido Guenther "); MODULE_DESCRIPTION("Hardware Watchdog Device for SGI IP22"); MODULE_LICENSE("GPL"); 7f6dfba96c543e55b6672d5a37e'>39cb2c9a316e77f6dfba96c543e55b6672d5a37e (patch) tree98fe974ee4e20121253de7f61fc8d01bdb3821c1 /net/llc 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 'net/llc')