/* * w1_int.c * * Copyright (c) 2004 Evgeniy Polyakov * * * 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. * * 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, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include #include #include #include #include "w1.h" #include "w1_log.h" #include "w1_netlink.h" #include "w1_int.h" static int w1_search_count = -1; /* Default is continual scan */ module_param_named(search_count, w1_search_count, int, 0); static int w1_enable_pullup = 1; module_param_named(enable_pullup, w1_enable_pullup, int, 0); static struct w1_master *w1_alloc_dev(u32 id, int slave_count, int slave_ttl, struct device_driver *driver, struct device *device) { struct w1_master *dev; int err; /* * We are in process context(kernel thread), so can sleep. */ dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL); if (!dev) { pr_err("Failed to allocate %zd bytes for new w1 device.\n", sizeof(struct w1_master)); return NULL; } dev->bus_master = (struct w1_bus_master *)(dev + 1); dev->owner = THIS_MODULE; dev->max_slave_count = slave_count; dev->slave_count = 0; dev->attempts = 0; dev->initialized = 0; dev->id = id; dev->slave_ttl = slave_ttl; dev->search_count = w1_search_count; dev->enable_pullup = w1_enable_pullup; /* 1 for w1_process to decrement * 1 for __w1_remove_master_device to decrement */ atomic_set(&dev->refcnt, 2); INIT_LIST_HEAD(&dev->slist); INIT_LIST_HEAD(&dev->async_list); mutex_init(&dev->mutex); mutex_init(&dev->bus_mutex); mutex_init(&dev->list_mutex); memcpy(&dev->dev, device, sizeof(struct device)); dev_set_name(&dev->dev, "w1_bus_master%u", dev->id); snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id); dev->dev.init_name = dev->name; dev->driver = driver; dev->seq = 1; err = device_register(&dev->dev); if (err) { pr_err("Failed to register master device. err=%d\n", err); put_device(&dev->dev); dev = NULL; } return dev; } static void w1_free_dev(struct w1_master *dev) { device_unregister(&dev->dev); } /** * w1_add_master_device() - registers a new master device * @master: master bus device to register */ int w1_add_master_device(struct w1_bus_master *master) { struct w1_master *dev, *entry; int retval = 0; struct w1_netlink_msg msg; int id, found; /* validate minimum functionality */ if (!(master->touch_bit && master->reset_bus) && !(master->write_bit && master->read_bit) && !(master->write_byte && master->read_byte && master->reset_bus)) { pr_err("w1_add_master_device: invalid function set\n"); return(-EINVAL); } /* Lock until the device is added (or not) to w1_masters. */ mutex_lock(&w1_mlock); /* Search for the first available id (starting at 1). */ id = 0; do { ++id; found = 0; list_for_each_entry(entry, &w1_masters, w1_master_entry) { if (entry->id == id) { found = 1; break; } } } while (found); dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device); if (!dev) { mutex_unlock(&w1_mlock); return -ENOMEM; } retval = w1_create_master_attributes(dev); if (retval) { mutex_unlock(&w1_mlock); goto err_out_free_dev; } memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); dev->initialized = 1; dev->thread = kthread_run(&w1_process, dev, "%s", dev->name); if (IS_ERR(dev->thread)) { retval = PTR_ERR(dev->thread); dev_err(&dev->dev, "Failed to create new kernel thread. err=%d\n", retval); mutex_unlock(&w1_mlock); goto err_out_rm_attr; } list_add(&dev->w1_master_entry, &w1_masters); mutex_unlock(&w1_mlock); memset(&msg, 0, sizeof(msg)); msg.id.mst.id = dev->id; msg.type = W1_MASTER_ADD; w1_netlink_send(dev, &msg); return 0; #if 0 /* Thread cleanup code, not required currently. */ err_out_kill_thread: set_bit(W1_ABORT_SEARCH, &dev->flags); kthread_stop(dev->thread); #endif err_out_rm_attr: w1_destroy_master_attributes(dev); err_out_free_dev: w1_free_dev(dev); return retval; } void __w1_remove_master_device(struct w1_master *dev) { struct w1_netlink_msg msg; struct w1_slave *sl, *sln; mutex_lock(&w1_mlock); list_del(&dev->w1_master_entry); mutex_unlock(&w1_mlock); set_bit(W1_ABORT_SEARCH, &dev->flags); kthread_stop(dev->thread); mutex_lock(&dev->mutex); mutex_lock(&dev->list_mutex); list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { mutex_unlock(&dev->list_mutex); w1_slave_detach(sl); mutex_lock(&dev->list_mutex); } w1_destroy_master_attributes(dev); mutex_unlock(&dev->list_mutex); mutex_unlock(&dev->mutex); atomic_dec(&dev->refcnt); while (atomic_read(&dev->refcnt)) { dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n", dev->name, atomic_read(&dev->refcnt)); if (msleep_interruptible(1000)) flush_signals(current); mutex_lock(&dev->list_mutex); w1_process_callbacks(dev); mutex_unlock(&dev->list_mutex); } mutex_lock(&dev->list_mutex); w1_process_callbacks(dev); mutex_unlock(&dev->list_mutex); memset(&msg, 0, sizeof(msg)); msg.id.mst.id = dev->id; msg.type = W1_MASTER_REMOVE; w1_netlink_send(dev, &msg); w1_free_dev(dev); } /** * w1_remove_master_device() - unregister a master device * @bm: master bus device to remove */ void w1_remove_master_device(struct w1_bus_master *bm) { struct w1_master *dev, *found = NULL; list_for_each_entry(dev, &w1_masters, w1_master_entry) { if (!dev->initialized) continue; if (dev->bus_master->data == bm->data) { found = dev; break; } } if (!found) { pr_err("Device doesn't exist.\n"); return; } __w1_remove_master_device(found); } EXPORT_SYMBOL(w1_add_master_device); EXPORT_SYMBOL(w1_remove_master_device); ened 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 'tools/perf/pmu-events/arch')