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, 153 insertions, 0 deletions

diff --git a/include/drm/drm_managed.h b/include/drm/drm_managed.h
new file mode 100644
index 000000000..72d0d68be
--- /dev/null
+++ b/include/drm/drm_managed.h
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#ifndef _DRM_MANAGED_H_
+#define _DRM_MANAGED_H_
+
+#include <linux/gfp.h>
+#include <linux/overflow.h>
+#include <linux/types.h>
+
+struct drm_device;
+struct mutex;
+
+typedef void (*drmres_release_t)(struct drm_device *dev, void *res);
+
+/**
+ * drmm_add_action - add a managed release action to a &drm_device
+ * @dev: DRM device
+ * @action: function which should be called when @dev is released
+ * @data: opaque pointer, passed to @action
+ *
+ * This function adds the release @action with optional parameter @data to the
+ * list of cleanup actions for @dev. The cleanup actions will be run in reverse
+ * order in the final drm_dev_put() call for @dev.
+ */
+#define drmm_add_action(dev, action, data) \
+	__drmm_add_action(dev, action, data, #action)
+
+int __must_check __drmm_add_action(struct drm_device *dev,
+				   drmres_release_t action,
+				   void *data, const char *name);
+
+/**
+ * drmm_add_action_or_reset - add a managed release action to a &drm_device
+ * @dev: DRM device
+ * @action: function which should be called when @dev is released
+ * @data: opaque pointer, passed to @action
+ *
+ * Similar to drmm_add_action(), with the only difference that upon failure
+ * @action is directly called for any cleanup work necessary on failures.
+ */
+#define drmm_add_action_or_reset(dev, action, data) \
+	__drmm_add_action_or_reset(dev, action, data, #action)
+
+int __must_check __drmm_add_action_or_reset(struct drm_device *dev,
+					    drmres_release_t action,
+					    void *data, const char *name);
+
+void drmm_release_action(struct drm_device *dev,
+			 drmres_release_t action,
+			 void *data);
+
+void *drmm_kmalloc(struct drm_device *dev, size_t size, gfp_t gfp) __malloc;
+
+/**
+ * drmm_kzalloc - &drm_device managed kzalloc()
+ * @dev: DRM device
+ * @size: size of the memory allocation
+ * @gfp: GFP allocation flags
+ *
+ * This is a &drm_device managed version of kzalloc(). The allocated memory is
+ * automatically freed on the final drm_dev_put(). Memory can also be freed
+ * before the final drm_dev_put() by calling drmm_kfree().
+ */
+static inline void *drmm_kzalloc(struct drm_device *dev, size_t size, gfp_t gfp)
+{
+	return drmm_kmalloc(dev, size, gfp | __GFP_ZERO);
+}
+
+/**
+ * drmm_kmalloc_array - &drm_device managed kmalloc_array()
+ * @dev: DRM device
+ * @n: number of array elements to allocate
+ * @size: size of array member
+ * @flags: GFP allocation flags
+ *
+ * This is a &drm_device managed version of kmalloc_array(). The allocated
+ * memory is automatically freed on the final drm_dev_put() and works exactly
+ * like a memory allocation obtained by drmm_kmalloc().
+ */
+static inline void *drmm_kmalloc_array(struct drm_device *dev,
+				       size_t n, size_t size, gfp_t flags)
+{
+	size_t bytes;
+
+	if (unlikely(check_mul_overflow(n, size, &bytes)))
+		return NULL;
+
+	return drmm_kmalloc(dev, bytes, flags);
+}
+
+/**
+ * drmm_kcalloc - &drm_device managed kcalloc()
+ * @dev: DRM device
+ * @n: number of array elements to allocate
+ * @size: size of array member
+ * @flags: GFP allocation flags
+ *
+ * This is a &drm_device managed version of kcalloc(). The allocated memory is
+ * automatically freed on the final drm_dev_put() and works exactly like a
+ * memory allocation obtained by drmm_kmalloc().
+ */
+static inline void *drmm_kcalloc(struct drm_device *dev,
+				 size_t n, size_t size, gfp_t flags)
+{
+	return drmm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
+}
+
+char *drmm_kstrdup(struct drm_device *dev, const char *s, gfp_t gfp);
+
+void drmm_kfree(struct drm_device *dev, void *data);
+
+void __drmm_mutex_release(struct drm_device *dev, void *res);
+
+/**
+ * drmm_mutex_init - &drm_device-managed mutex_init()
+ * @dev: DRM device
+ * @lock: lock to be initialized
+ *
+ * Returns:
+ * 0 on success, or a negative errno code otherwise.
+ *
+ * This is a &drm_device-managed version of mutex_init(). The initialized
+ * lock is automatically destroyed on the final drm_dev_put().
+ */
+#define drmm_mutex_init(dev, lock) ({					     \
+	mutex_init(lock);						     \
+	drmm_add_action_or_reset(dev, __drmm_mutex_release, lock);	     \
+})									     \
+
+void __drmm_workqueue_release(struct drm_device *device, void *wq);
+
+/**
+ * drmm_alloc_ordered_workqueue - &drm_device managed alloc_ordered_workqueue()
+ * @dev: DRM device
+ * @fmt: printf format for the name of the workqueue
+ * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
+ * @args: args for @fmt
+ *
+ * This is a &drm_device-managed version of alloc_ordered_workqueue(). The
+ * allocated workqueue is automatically destroyed on the final drm_dev_put().
+ *
+ * Returns: workqueue on success, negative ERR_PTR otherwise.
+ */
+#define drmm_alloc_ordered_workqueue(dev, fmt, flags, args...)					\
+	({											\
+		struct workqueue_struct *wq = alloc_ordered_workqueue(fmt, flags, ##args);	\
+		wq ? ({										\
+			int ret = drmm_add_action_or_reset(dev, __drmm_workqueue_release, wq);	\
+			ret ? ERR_PTR(ret) : wq;						\
+		}) : ERR_PTR(-ENOMEM);								\
+	})
+
+#endif