Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 326 insertions, 0 deletions

diff --git a/drivers/base/base.h b/drivers/base/base.h
new file mode 100644
index 000000000..a5b7abc10
--- /dev/null
+++ b/drivers/base/base.h
@@ -0,0 +1,326 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2001-2003 Patrick Mochel <mochel@osdl.org>
+ * Copyright (c) 2004-2009 Greg Kroah-Hartman <gregkh@suse.de>
+ * Copyright (c) 2008-2012 Novell Inc.
+ * Copyright (c) 2012-2019 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+ * Copyright (c) 2012-2019 Linux Foundation
+ *
+ * Core driver model functions and structures that should not be
+ * shared outside of the drivers/base/ directory.
+ *
+ */
+#include <linux/notifier.h>
+
+/**
+ * struct subsys_private - structure to hold the private to the driver core
+ *			   portions of the bus_type/class structure.
+ * @subsys: the struct kset that defines this subsystem
+ * @devices_kset: the subsystem's 'devices' directory
+ * @interfaces: list of subsystem interfaces associated
+ * @mutex: protect the devices, and interfaces lists.
+ * @drivers_kset: the list of drivers associated
+ * @klist_devices: the klist to iterate over the @devices_kset
+ * @klist_drivers: the klist to iterate over the @drivers_kset
+ * @bus_notifier: the bus notifier list for anything that cares about things
+ *		  on this bus.
+ * @drivers_autoprobe: gate whether new devices are automatically attached to
+ *		       registered drivers, or new drivers automatically attach
+ *		       to existing devices.
+ * @bus: pointer back to the struct bus_type that this structure is associated
+ *	 with.
+ * @dev_root: Default device to use as the parent.
+ * @glue_dirs: "glue" directory to put in-between the parent device to
+ *	       avoid namespace conflicts
+ * @class: pointer back to the struct class that this structure is associated
+ *	   with.
+ * @lock_key: Lock class key for use by the lock validator
+ *
+ * This structure is the one that is the actual kobject allowing struct
+ * bus_type/class to be statically allocated safely.  Nothing outside of the
+ * driver core should ever touch these fields.
+ */
+struct subsys_private {
+	struct kset subsys;
+	struct kset *devices_kset;
+	struct list_head interfaces;
+	struct mutex mutex;
+
+	struct kset *drivers_kset;
+	struct klist klist_devices;
+	struct klist klist_drivers;
+	struct blocking_notifier_head bus_notifier;
+	unsigned int drivers_autoprobe:1;
+	const struct bus_type *bus;
+	struct device *dev_root;
+
+	struct kset glue_dirs;
+	const struct class *class;
+
+	struct lock_class_key lock_key;
+};
+#define to_subsys_private(obj) container_of_const(obj, struct subsys_private, subsys.kobj)
+
+static inline struct subsys_private *subsys_get(struct subsys_private *sp)
+{
+	if (sp)
+		kset_get(&sp->subsys);
+	return sp;
+}
+
+static inline void subsys_put(struct subsys_private *sp)
+{
+	if (sp)
+		kset_put(&sp->subsys);
+}
+
+struct subsys_private *bus_to_subsys(const struct bus_type *bus);
+struct subsys_private *class_to_subsys(const struct class *class);
+
+struct driver_private {
+	struct kobject kobj;
+	struct klist klist_devices;
+	struct klist_node knode_bus;
+	struct module_kobject *mkobj;
+	struct device_driver *driver;
+};
+#define to_driver(obj) container_of(obj, struct driver_private, kobj)
+
+/**
+ * struct device_private - structure to hold the private to the driver core
+ *			   portions of the device structure.
+ * @klist_children: klist containing all children of this device
+ * @knode_parent: node in sibling list
+ * @knode_driver: node in driver list
+ * @knode_bus: node in bus list
+ * @knode_class: node in class list
+ * @deferred_probe: entry in deferred_probe_list which is used to retry the
+ *		    binding of drivers which were unable to get all the
+ *		    resources needed by the device; typically because it depends
+ *		    on another driver getting probed first.
+ * @async_driver: pointer to device driver awaiting probe via async_probe
+ * @deferred_probe_reason: capture the -EPROBE_DEFER message emitted with
+ *			   dev_err_probe() for later retrieval via debugfs
+ * @device: pointer back to the struct device that this structure is
+ *	    associated with.
+ * @dead: This device is currently either in the process of or has been
+ *	  removed from the system. Any asynchronous events scheduled for this
+ *	  device should exit without taking any action.
+ *
+ * Nothing outside of the driver core should ever touch these fields.
+ */
+struct device_private {
+	struct klist klist_children;
+	struct klist_node knode_parent;
+	struct klist_node knode_driver;
+	struct klist_node knode_bus;
+	struct klist_node knode_class;
+	struct list_head deferred_probe;
+	const struct device_driver *async_driver;
+	char *deferred_probe_reason;
+	struct device *device;
+	u8 dead:1;
+};
+#define to_device_private_parent(obj)	\
+	container_of(obj, struct device_private, knode_parent)
+#define to_device_private_driver(obj)	\
+	container_of(obj, struct device_private, knode_driver)
+#define to_device_private_bus(obj)	\
+	container_of(obj, struct device_private, knode_bus)
+#define to_device_private_class(obj)	\
+	container_of(obj, struct device_private, knode_class)
+
+/* initialisation functions */
+int devices_init(void);
+int buses_init(void);
+int classes_init(void);
+int firmware_init(void);
+#ifdef CONFIG_SYS_HYPERVISOR
+int hypervisor_init(void);
+#else
+static inline int hypervisor_init(void) { return 0; }
+#endif
+int platform_bus_init(void);
+int faux_bus_init(void);
+void cpu_dev_init(void);
+void container_dev_init(void);
+#ifdef CONFIG_AUXILIARY_BUS
+void auxiliary_bus_init(void);
+#else
+static inline void auxiliary_bus_init(void) { }
+#endif
+
+struct kobject *virtual_device_parent(void);
+
+int bus_add_device(struct device *dev);
+void bus_probe_device(struct device *dev);
+void bus_remove_device(struct device *dev);
+void bus_notify(struct device *dev, enum bus_notifier_event value);
+bool bus_is_registered(const struct bus_type *bus);
+
+int bus_add_driver(struct device_driver *drv);
+void bus_remove_driver(struct device_driver *drv);
+void device_release_driver_internal(struct device *dev, const struct device_driver *drv,
+				    struct device *parent);
+
+void driver_detach(const struct device_driver *drv);
+void driver_deferred_probe_del(struct device *dev);
+void device_set_deferred_probe_reason(const struct device *dev, struct va_format *vaf);
+static inline int driver_match_device(const struct device_driver *drv,
+				      struct device *dev)
+{
+	return drv->bus->match ? drv->bus->match(dev, drv) : 1;
+}
+
+static inline bool dev_has_sync_state(struct device *dev)
+{
+	struct device_driver *drv;
+
+	if (!dev)
+		return false;
+	drv = READ_ONCE(dev->driver);
+	if (drv && drv->sync_state)
+		return true;
+	if (dev->bus && dev->bus->sync_state)
+		return true;
+	return false;
+}
+
+static inline void dev_sync_state(struct device *dev)
+{
+	if (dev->bus->sync_state)
+		dev->bus->sync_state(dev);
+	else if (dev->driver && dev->driver->sync_state)
+		dev->driver->sync_state(dev);
+}
+
+int driver_add_groups(const struct device_driver *drv,
+		      const struct attribute_group *const *groups);
+void driver_remove_groups(const struct device_driver *drv,
+			  const struct attribute_group *const *groups);
+void device_driver_detach(struct device *dev);
+
+static inline void device_set_driver(struct device *dev, const struct device_driver *drv)
+{
+	/*
+	 * Majority (all?) read accesses to dev->driver happens either
+	 * while holding device lock or in bus/driver code that is only
+	 * invoked when the device is bound to a driver and there is no
+	 * concern of the pointer being changed while it is being read.
+	 * However when reading device's uevent file we read driver pointer
+	 * without taking device lock (so we do not block there for
+	 * arbitrary amount of time). We use WRITE_ONCE() here to prevent
+	 * tearing so that READ_ONCE() can safely be used in uevent code.
+	 */
+	// FIXME - this cast should not be needed "soon"
+	WRITE_ONCE(dev->driver, (struct device_driver *)drv);
+}
+
+struct devres_node;
+typedef void (*dr_node_release_t)(struct device *dev, struct devres_node *node);
+typedef void (*dr_node_free_t)(struct devres_node *node);
+
+struct devres_node {
+	struct list_head		entry;
+	dr_node_release_t		release;
+	dr_node_free_t			free_node;
+	const char			*name;
+	size_t				size;
+};
+
+void devres_node_init(struct devres_node *node, dr_node_release_t release,
+		      dr_node_free_t free_node);
+void devres_node_add(struct device *dev, struct devres_node *node);
+bool devres_node_remove(struct device *dev, struct devres_node *node);
+void devres_set_node_dbginfo(struct devres_node *node, const char *name,
+			     size_t size);
+void devres_for_each_res(struct device *dev, dr_release_t release,
+			 dr_match_t match, void *match_data,
+			 void (*fn)(struct device *, void *, void *),
+			 void *data);
+int devres_release_all(struct device *dev);
+void device_block_probing(void);
+void device_unblock_probing(void);
+void deferred_probe_extend_timeout(void);
+void driver_deferred_probe_trigger(void);
+const char *device_get_devnode(const struct device *dev, umode_t *mode,
+			       kuid_t *uid, kgid_t *gid, const char **tmp);
+
+/* /sys/devices directory */
+extern struct kset *devices_kset;
+void devices_kset_move_last(struct device *dev);
+
+#if defined(CONFIG_MODULES) && defined(CONFIG_SYSFS)
+int module_add_driver(struct module *mod, const struct device_driver *drv);
+void module_remove_driver(const struct device_driver *drv);
+#else
+static inline int module_add_driver(struct module *mod,
+				    struct device_driver *drv)
+{
+	return 0;
+}
+static inline void module_remove_driver(struct device_driver *drv) { }
+#endif
+
+#ifdef CONFIG_DEVTMPFS
+int devtmpfs_init(void);
+#else
+static inline int devtmpfs_init(void) { return 0; }
+#endif
+
+#ifdef CONFIG_BLOCK
+extern const struct class block_class;
+static inline bool is_blockdev(struct device *dev)
+{
+	return dev->class == &block_class;
+}
+#else
+static inline bool is_blockdev(struct device *dev) { return false; }
+#endif
+
+/* Device links support */
+int device_links_read_lock(void);
+void device_links_read_unlock(int idx);
+int device_links_read_lock_held(void);
+int device_links_check_suppliers(struct device *dev);
+void device_links_force_bind(struct device *dev);
+void device_links_driver_bound(struct device *dev);
+void device_links_driver_cleanup(struct device *dev);
+void device_links_no_driver(struct device *dev);
+bool device_links_busy(struct device *dev);
+void device_links_unbind_consumers(struct device *dev);
+bool device_link_flag_is_sync_state_only(u32 flags);
+void fw_devlink_drivers_done(void);
+void fw_devlink_probing_done(void);
+
+#define dev_for_each_link_to_supplier(__link, __dev)	\
+	list_for_each_entry_srcu(__link, &(__dev)->links.suppliers, c_node, \
+				 device_links_read_lock_held())
+
+#define dev_for_each_link_to_consumer(__link, __dev)	\
+	list_for_each_entry_srcu(__link, &(__dev)->links.consumers, s_node, \
+				 device_links_read_lock_held())
+
+/* device pm support */
+void device_pm_move_to_tail(struct device *dev);
+
+#ifdef CONFIG_DEVTMPFS
+int devtmpfs_create_node(struct device *dev);
+int devtmpfs_delete_node(struct device *dev);
+#else
+static inline int devtmpfs_create_node(struct device *dev) { return 0; }
+static inline int devtmpfs_delete_node(struct device *dev) { return 0; }
+#endif
+
+void software_node_init(void);
+void software_node_notify(struct device *dev);
+void software_node_notify_remove(struct device *dev);
+
+#ifdef CONFIG_PINCTRL
+int pinctrl_bind_pins(struct device *dev);
+#else
+static inline int pinctrl_bind_pins(struct device *dev)
+{
+	return 0;
+}
+#endif /* CONFIG_PINCTRL */