Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

include/linux/ring_buffer.h

@@ -3,8 +3,9 @@
 #define _LINUX_RING_BUFFER_H
 
 #include <linux/mm.h>
-#include <linux/seq_file.h>
 #include <linux/poll.h>
+#include <linux/ring_buffer_types.h>
+#include <linux/seq_file.h>
 
 #include <uapi/linux/trace_mmap.h>
 
@@ -279,11 +280,25 @@ static inline struct ring_buffer_desc *__first_ring_buffer_desc(struct trace_buf
 	return (struct ring_buffer_desc *)(&desc->__data[0]);
 }
 
+/*
+ * Returns the number of pages for a ring_buffer_desc. The caller must ensure it
+ * does not overflow ring_buffer_desc::nr_page_va.
+ */
+static inline unsigned long __calc_nr_pages_ring_buffer_desc(size_t size)
+{
+	/* Takes into account the reader page */
+	return max(DIV_ROUND_UP(size, PAGE_SIZE - BUF_PAGE_HDR_SIZE), 2UL) + 1;
+}
+
 static inline size_t trace_buffer_desc_size(size_t buffer_size, unsigned int nr_cpus)
 {
-	unsigned int nr_pages = max(DIV_ROUND_UP(buffer_size, PAGE_SIZE), 2UL) + 1;
+	unsigned long nr_pages = __calc_nr_pages_ring_buffer_desc(buffer_size);
 	struct ring_buffer_desc *rbdesc;
 
+	/* Capped by ring_buffer_desc::nr_page_va */
+	if (nr_pages > UINT_MAX)
+		return SIZE_MAX;
+
 	return size_add(offsetof(struct trace_buffer_desc, __data),
 			size_mul(nr_cpus, struct_size(rbdesc, page_va, nr_pages)));
 }

include/trace/events/timer.h

@@ -302,7 +302,7 @@ DECLARE_EVENT_CLASS(hrtimer_class,
  * hrtimer_start_expired - Invoked when a expired timer was started
  * @hrtimer:	pointer to struct hrtimer
  *
- * Preceeded by a hrtimer_start tracepoint.
+ * Preceded by a hrtimer_start tracepoint.
  */
 DEFINE_EVENT(hrtimer_class, hrtimer_start_expired,
 

kernel/fork.c

@@ -2133,6 +2133,11 @@ __latent_entropy struct task_struct *copy_process(
 	p = dup_task_struct(current, node);
 	if (!p)
 		goto fork_out;
+	/*
+	 * Must run before the first fallible op, so error paths never
+	 * free the parent's ret_stack.
+	 */
+	ftrace_graph_init_task(p);
 	retval = copy_exec_state(clone_flags, p);
 	if (retval)
 		goto bad_fork_free;
@@ -2159,8 +2164,6 @@ __latent_entropy struct task_struct *copy_process(
 	 */
 	p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? args->child_tid : NULL;
 
-	ftrace_graph_init_task(p);
-
 	rt_mutex_init_task(p);
 	raw_spin_lock_init(&p->blocked_lock);
 

kernel/trace/fgraph.c

@@ -143,9 +143,6 @@ enum {
 #define FGRAPH_DATA_INDEX_MASK	GENMASK(FGRAPH_DATA_INDEX_BITS - 1, 0)
 #define FGRAPH_DATA_INDEX_SHIFT	(FGRAPH_DATA_SHIFT + FGRAPH_DATA_BITS)
 
-#define FGRAPH_MAX_INDEX	\
-	((FGRAPH_INDEX_SIZE << FGRAPH_DATA_BITS) + FGRAPH_RET_INDEX)
-
 #define FGRAPH_ARRAY_SIZE	FGRAPH_INDEX_BITS
 
 /*

kernel/trace/ftrace.c

@@ -6675,7 +6675,7 @@ int update_ftrace_direct_mod(struct ftrace_ops *ops, struct ftrace_hash *hash, b
 
 	/* Enable the tmp_ops to have the same functions as the hash object. */
 	ftrace_ops_init(&tmp_ops);
-	tmp_ops.func_hash->filter_hash = hash;
+	rcu_assign_pointer(tmp_ops.func_hash->filter_hash, hash);
 
 	err = register_ftrace_function_nolock(&tmp_ops);
 	if (err)

kernel/trace/rethook.c

@@ -171,7 +171,7 @@ struct rethook_node *rethook_try_get(struct rethook *rh)
 	 * This expects the caller will set up a rethook on a function entry.
 	 * When the function returns, the rethook will eventually be reclaimed
 	 * or released in the rethook_recycle() with call_rcu().
-	 * This means the caller must be run in the RCU-availabe context.
+	 * This means the caller must be run in the RCU-available context.
 	 */
 	if (unlikely(!rcu_is_watching()))
 		return NULL;

kernel/trace/ring_buffer.c

@@ -904,14 +904,13 @@ static void rb_wake_up_waiters(struct irq_work *work)
 		struct ring_buffer_per_cpu *cpu_buffer =
 			container_of(rbwork, struct ring_buffer_per_cpu, irq_work);
 
-		/* Called from interrupt context */
-		raw_spin_lock(&cpu_buffer->reader_lock);
-		rbwork->wakeup_full = false;
-		rbwork->full_waiters_pending = false;
+		scoped_guard(raw_spinlock_irqsave, &cpu_buffer->reader_lock) {
+			rbwork->wakeup_full = false;
+			rbwork->full_waiters_pending = false;
 
-		/* Waking up all waiters, they will reset the shortest full */
-		cpu_buffer->shortest_full = 0;
-		raw_spin_unlock(&cpu_buffer->reader_lock);
+			/* Waking up all waiters, they will reset the shortest full */
+			cpu_buffer->shortest_full = 0;
+		}
 
 		wake_up_all(&rbwork->full_waiters);
 	}
@@ -7384,7 +7383,7 @@ EXPORT_SYMBOL_GPL(ring_buffer_read_page_data);
 
 /**
  * ring_buffer_read_page_size - get size of the read page.
- * @page:  the page to get the size from
+ * @rpage:  the page to get the size from
  *
  * Returns size of the page in bytes.
  */
@@ -7474,6 +7473,14 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order)
 
 	old_capacity = rb_subbuf_capacity(buffer);
 
+	/* The mmap fast path reads subbuf_order without buffer->mutex. */
+	for_each_buffer_cpu(buffer, cpu) {
+		if (!cpumask_test_cpu(cpu, buffer->cpumask))
+			continue;
+		if (atomic_read(&buffer->buffers[cpu]->resize_disabled))
+			return -EBUSY;
+	}
+
 	atomic_inc(&buffer->record_disabled);
 
 	/* Make sure all commits have finished */

kernel/trace/trace.c

@@ -7717,12 +7717,55 @@ trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
 	return cnt;
 }
 
+static bool tr_option_match(struct trace_array *tr, void *topt)
+{
+	for (int i = 0; i < tr->nr_topts; i++) {
+		struct trace_options *tr_topts = &tr->topts[i];
+
+		if (topt >= (void *)&tr_topts->topts[0] &&
+		    topt < (void *)&tr_topts->topts[tr_topts->nr_topts])
+			return true;
+	}
+	return false;
+}
+
+/*
+ * The topt is the address of a trace_array->topts[] element that holds the
+ * the tracer options descriptor. But since the trace_array reference has not
+ * been taken yet, it cannot be dereferenced as it could have been freed by
+ * a rmdir of the instance the trace_array represents.
+ *
+ * Search the list of trace_arrays and compare the topt to the address of
+ * the entire trace_array topts array for each trace_array in the list.
+ * If one is matched, then take the reference and return it. If not, the
+ * trace_array no longer exits.
+ */
+static int trace_array_tracer_options_get(void *topt)
+{
+	struct trace_array *tr;
+	int ret;
+
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
+	if (tracing_disabled)
+		return -ENODEV;
+
+	guard(mutex)(&trace_types_lock);
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		if (tr_option_match(tr, topt))
+			return __trace_array_get(tr);
+	}
+	return -ENODEV;
+}
+
 static int tracing_open_options(struct inode *inode, struct file *filp)
 {
 	struct trace_option_dentry *topt = inode->i_private;
 	int ret;
 
-	ret = tracing_check_open_get_tr(topt->tr);
+	ret = trace_array_tracer_options_get(topt);
 	if (ret)
 		return ret;
 
@@ -7984,6 +8027,7 @@ create_trace_option_files(struct trace_array *tr, struct tracer *tracer,
 	tr->topts = tr_topts;
 	tr->topts[tr->nr_topts].tracer = tracer;
 	tr->topts[tr->nr_topts].topts = topts;
+	tr->topts[tr->nr_topts].nr_topts = cnt;
 	tr->nr_topts++;
 
 	for (cnt = 0; opts[cnt].name; cnt++) {

kernel/trace/trace.h

@@ -227,6 +227,7 @@ struct array_buffer {
 struct trace_options {
 	struct tracer			*tracer;
 	struct trace_option_dentry	*topts;
+	int				nr_topts;
 };
 
 struct trace_pid_list *trace_pid_list_alloc(void);
@@ -1952,6 +1953,7 @@ struct event_trigger_data {
 
 struct enable_trigger_data {
 	struct trace_event_file		*file;
+	struct trace_event_call		*call;
 	bool				enable;
 	bool				hist;
 };

kernel/trace/trace_events.c

@@ -1489,6 +1489,8 @@ int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
 	/* Put back the colon to allow this to be called again */
 	if (buf)
 		*(buf - 1) = ':';
+	if (mod)
+		*(mod - 5) = ':';
 
 	return ret;
 }

kernel/trace/trace_events_hist.c

@@ -169,7 +169,6 @@ struct hist_field {
 	struct hist_field		*operands[HIST_FIELD_OPERANDS_MAX];
 	struct hist_trigger_data	*hist_data;
 	enum hist_field_fn		fn_num;
-	unsigned int			ref;
 	unsigned int			size;
 	unsigned int			offset;
 	unsigned int                    is_signed;
@@ -1913,16 +1912,8 @@ out:
 	return field_op;
 }
 
-static void get_hist_field(struct hist_field *hist_field)
-{
-	hist_field->ref++;
-}
-
 static void __destroy_hist_field(struct hist_field *hist_field)
 {
-	if (--hist_field->ref > 1)
-		return;
-
 	kfree(hist_field->var.name);
 	kfree(hist_field->name);
 
@@ -1969,8 +1960,6 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
 	if (!hist_field)
 		return NULL;
 
-	hist_field->ref = 1;
-
 	hist_field->hist_data = hist_data;
 
 	if (flags & HIST_FIELD_FL_EXPR || flags & HIST_FIELD_FL_ALIAS)
@@ -2223,10 +2212,8 @@ static struct hist_field *create_var_ref(struct hist_trigger_data *hist_data,
 	for (i = 0; i < hist_data->n_var_refs; i++) {
 		ref_field = hist_data->var_refs[i];
 		if (ref_field->var.idx == var_field->var.idx &&
-		    ref_field->var.hist_data == var_field->hist_data) {
-			get_hist_field(ref_field);
+		    ref_field->var.hist_data == var_field->hist_data)
 			return ref_field;
-		}
 	}
 	/* Sanity check to avoid out-of-bound write on 'hist_data->var_refs' */
 	if (hist_data->n_var_refs >= TRACING_MAP_VARS_MAX)
@@ -2234,7 +2221,7 @@ static struct hist_field *create_var_ref(struct hist_trigger_data *hist_data,
 	ref_field = create_hist_field(var_field->hist_data, NULL, flags, NULL);
 	if (ref_field) {
 		if (init_var_ref(ref_field, var_field, system, event_name)) {
-			destroy_hist_field(ref_field, 0);
+			__destroy_hist_field(ref_field);
 			return NULL;
 		}
 
@@ -2330,6 +2317,7 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
 	struct ftrace_event_field *field = NULL;
 	char *field_name, *modifier, *str;
 	struct trace_array *tr = file->tr;
+	bool stack_modifier = false;
 
 	modifier = str = kstrdup(field_str, GFP_KERNEL);
 	if (!modifier)
@@ -2352,9 +2340,10 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
 			*flags |= HIST_FIELD_FL_EXECNAME;
 		else if (strcmp(modifier, "syscall") == 0)
 			*flags |= HIST_FIELD_FL_SYSCALL;
-		else if (strcmp(modifier, "stacktrace") == 0)
+		else if (strcmp(modifier, "stacktrace") == 0) {
 			*flags |= HIST_FIELD_FL_STACKTRACE;
-		else if (strcmp(modifier, "log2") == 0)
+			stack_modifier = true;
+		} else if (strcmp(modifier, "log2") == 0)
 			*flags |= HIST_FIELD_FL_LOG2;
 		else if (strcmp(modifier, "usecs") == 0)
 			*flags |= HIST_FIELD_FL_TIMESTAMP_USECS;
@@ -2415,6 +2404,7 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
 				*flags |= HIST_FIELD_FL_CPU;
 			} else if (field && field->filter_type == FILTER_STACKTRACE) {
 				*flags |= HIST_FIELD_FL_STACKTRACE;
+				field = NULL;
 			} else if (field && field->filter_type == FILTER_COMM) {
 				*flags |= HIST_FIELD_FL_COMM | HIST_FIELD_FL_STRING;
 			} else {
@@ -2425,6 +2415,12 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
 			}
 		}
 	}
+
+	if (stack_modifier &&
+	    (!field || field->filter_type != FILTER_STACKTRACE)) {
+		hist_err(tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(field_str));
+		field = ERR_PTR(-EINVAL);
+	}
  out:
 	kfree(str);
 
@@ -3276,7 +3272,6 @@ static struct hist_field *create_var(struct hist_trigger_data *hist_data,
 		goto out;
 	}
 
-	var->ref = 1;
 	var->flags = HIST_FIELD_FL_VAR;
 	var->var.idx = idx;
 	var->var.hist_data = var->hist_data = hist_data;
@@ -4313,8 +4308,7 @@ static int __create_val_field(struct hist_trigger_data *hist_data,
 			goto err;
 	} else {
 		/* Value */
-		if (hist_field->flags & (HIST_FIELD_FL_GRAPH | HIST_FIELD_FL_PERCENT |
-					 HIST_FIELD_FL_BUCKET | HIST_FIELD_FL_LOG2 |
+		if (hist_field->flags & (HIST_FIELD_FL_BUCKET | HIST_FIELD_FL_LOG2 |
 					 HIST_FIELD_FL_SYM | HIST_FIELD_FL_SYM_OFFSET |
 					 HIST_FIELD_FL_SYSCALL | HIST_FIELD_FL_STACKTRACE))
 			goto err;
@@ -4331,6 +4325,7 @@ static int __create_val_field(struct hist_trigger_data *hist_data,
 	return ret;
  err:
 	hist_err(file->tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(field_str));
+	destroy_hist_field(hist_field, 0);
 	return -EINVAL;
 }
 
@@ -5690,7 +5685,7 @@ static int print_entries(struct seq_file *m,
 {
 	struct tracing_map_sort_entry **sort_entries = NULL;
 	struct tracing_map *map = hist_data->map;
-	int i, j, n_entries;
+	int i, j, n_entries, ret;
 	struct hist_val_stat *stats = NULL;
 	u64 val;
 
@@ -5700,6 +5695,8 @@ static int print_entries(struct seq_file *m,
 	if (n_entries < 0)
 		return n_entries;
 
+	ret = n_entries;
+
 	/* Calculate the max and the total for each field if needed. */
 	for (j = 0; j < hist_data->n_vals; j++) {
 		if (!(hist_data->fields[j]->flags &
@@ -5708,7 +5705,7 @@ static int print_entries(struct seq_file *m,
 		if (!stats) {
 			stats = kzalloc_objs(*stats, hist_data->n_vals);
 			if (!stats) {
-				n_entries = -ENOMEM;
+				ret = -ENOMEM;
 				goto out;
 			}
 		}
@@ -5729,7 +5726,7 @@ static int print_entries(struct seq_file *m,
 out:
 	tracing_map_destroy_sort_entries(sort_entries, n_entries);
 
-	return n_entries;
+	return ret;
 }
 
 static void hist_trigger_show(struct seq_file *m,
@@ -6383,17 +6380,18 @@ static int event_hist_trigger_named_init(struct event_trigger_data *data)
 {
 	int ret;
 
-	data->ref++;
-
-	save_named_trigger(data->named_data->name, data);
-
 	ret = event_hist_trigger_init(data->named_data);
 	if (ret < 0) {
 		kfree(data->cmd_ops);
 		data->cmd_ops = &trigger_hist_cmd;
+		return ret;
 	}
 
-	return ret;
+	data->ref++;
+
+	save_named_trigger(data->named_data->name, data);
+
+	return 0;
 }
 
 static void event_hist_trigger_named_free(struct event_trigger_data *data)
@@ -6643,12 +6641,6 @@ static int hist_register_trigger(char *glob,
 		data->cmd_ops = cmd_ops;
 	}
 
-	if (data->cmd_ops->init) {
-		ret = data->cmd_ops->init(data);
-		if (ret < 0)
-			goto out;
-	}
-
 	if (hist_data->enable_timestamps) {
 		char *clock = hist_data->attrs->clock;
 
@@ -6661,6 +6653,15 @@ static int hist_register_trigger(char *glob,
 		tracing_set_filter_buffering(file->tr, true);
 	}
 
+	if (data->cmd_ops->init) {
+		ret = data->cmd_ops->init(data);
+		if (ret < 0) {
+			if (hist_data->enable_timestamps)
+				tracing_set_filter_buffering(file->tr, false);
+			goto out;
+		}
+	}
+
 	if (named_data) {
 		remove_hist_vars(hist_data);
 		destroy_hist_data(hist_data);
@@ -6678,11 +6679,12 @@ static int hist_trigger_enable(struct event_trigger_data *data,
 
 	update_cond_flag(file);
 
-	if (trace_event_trigger_enable_disable(file, 1) < 0) {
-		list_del_rcu(&data->list);
-		update_cond_flag(file);
+	/*
+	 * On failure the caller undoes the registration, and
+	 * hist_unregister_trigger() can only find the trigger here.
+	 */
+	if (trace_event_trigger_enable_disable(file, 1) < 0)
 		ret--;
-	}
 
 	return ret;
 }
@@ -6760,13 +6762,13 @@ static void hist_unregister_trigger(char *glob,
 		}
 	}
 
-	if (test && test->cmd_ops->free)
-		test->cmd_ops->free(test);
-
 	if (hist_data->enable_timestamps) {
 		if (!hist_data->remove || test)
 			tracing_set_filter_buffering(file->tr, false);
 	}
+
+	if (test && test->cmd_ops->free)
+		test->cmd_ops->free(test);
 }
 
 static bool hist_file_check_refs(struct trace_event_file *file)
@@ -6971,6 +6973,8 @@ static int event_hist_trigger_parse(struct event_command *cmd_ops,
 	return ret;
  out_unreg:
 	event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
+	/* The unregister frees trigger_data, skip out_free */
+	goto out;
  out_free:
 	remove_hist_vars(hist_data);
 

kernel/trace/trace_events_trigger.c

@@ -1728,7 +1728,8 @@ static void enable_trigger_private_data_free(struct event_trigger_data *data)
 {
 	struct enable_trigger_data *enable_data = data->private_data;
 
-	trace_event_put_ref(enable_data->file->event_call);
+	/* The file may already be freed here, only the call is kept alive */
+	trace_event_put_ref(enable_data->call);
 	kfree(enable_data);
 }
 
@@ -1801,6 +1802,7 @@ int event_enable_trigger_parse(struct event_command *cmd_ops,
 	enable_data->hist = hist;
 	enable_data->enable = enable;
 	enable_data->file = event_enable_file;
+	enable_data->call = event_enable_file->event_call;
 
 	trigger_data = trigger_data_alloc(cmd_ops, cmd, param, enable_data);
 	if (!trigger_data)

kernel/trace/trace_events_user.c

@@ -1122,10 +1122,9 @@ static void user_event_destroy_validators(struct user_event *user)
 	}
 }
 
-static void user_event_destroy_fields(struct user_event *user)
+static void user_event_destroy_fields(struct list_head *head)
 {
 	struct ftrace_event_field *field, *next;
-	struct list_head *head = &user->fields;
 
 	list_for_each_entry_safe(field, next, head, link) {
 		list_del(&field->link);
@@ -1502,17 +1501,32 @@ static int user_event_set_call_visible(struct user_event *user, bool visible)
 
 static int destroy_user_event(struct user_event *user)
 {
+	LIST_HEAD(fields);
 	int ret = 0;
 
 	lockdep_assert_held(&event_mutex);
 
-	/* Must destroy fields before call removal */
-	user_event_destroy_fields(user);
+	/*
+	 * Detach the fields before removing the call. Removing the event
+	 * frees the field list memory (trace_destroy_fields() is run on
+	 * successful removal and kmem_cache_free()s the fields), but the
+	 * fields here are allocated and owned by user_events. Destroy
+	 * them separately once removal has succeeded.
+	 */
+	list_splice_init(&user->fields, &fields);
 
 	ret = user_event_set_call_visible(user, false);
 
-	if (ret)
+	if (ret) {
+		/*
+		 * Removal failed and the event stays registered, recover
+		 * the fields so it is left in a consistent state.
+		 */
+		list_splice(&fields, &user->fields);
 		return ret;
+	}
+
+	user_event_destroy_fields(&fields);
 
 	dyn_event_remove(&user->devent);
 	hash_del(&user->node);
@@ -2212,7 +2226,7 @@ static int user_event_parse(struct user_event_group *group, char *name,
 put_user_lock:
 	mutex_unlock(&event_mutex);
 put_user:
-	user_event_destroy_fields(user);
+	user_event_destroy_fields(&user->fields);
 	user_event_destroy_validators(user);
 	kfree(user->call.print_fmt);
 

kernel/trace/trace_functions_graph.c

@@ -52,6 +52,7 @@ struct fgraph_data {
 	};
 	struct ftrace_graph_ret_entry	ret;
 	int				failed;
+	int				ent_size;
 	int				cpu;
 };
 
@@ -1274,6 +1275,7 @@ print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
 		if (s->full) {
 			data->failed = 1;
 			data->cpu = cpu;
+			data->ent_size = iter->ent_size;
 		} else
 			data->failed = 0;
 	}
@@ -1457,6 +1459,7 @@ print_graph_function_flags(struct trace_iterator *iter, u32 flags)
 	if (data && data->failed) {
 		field = &data->ent.ent;
 		iter->cpu = data->cpu;
+		iter->ent_size = data->ent_size;
 		ret = print_graph_entry(field, s, iter, flags);
 		if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
 			per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;

kernel/trace/trace_remote.c

@@ -980,9 +980,12 @@ int trace_remote_alloc_buffer(struct trace_buffer_desc *desc, size_t desc_size,
 			      const struct cpumask *cpumask)
 {
 	size_t min_desc_size = trace_buffer_desc_size(buffer_size, cpumask_weight(cpumask));
-	unsigned int nr_pages = max(DIV_ROUND_UP(buffer_size, PAGE_SIZE), 2UL) + 1;
 	struct ring_buffer_desc *rb_desc;
 	int cpu, ret = -ENOMEM;
+	unsigned int nr_pages;
+
+	if (min_desc_size == SIZE_MAX)
+		return -E2BIG;
 
 	if (desc_size < min_desc_size)
 		return -EINVAL;
@@ -991,6 +994,7 @@ int trace_remote_alloc_buffer(struct trace_buffer_desc *desc, size_t desc_size,
 	desc->struct_len = min_desc_size;
 
 	rb_desc = __first_ring_buffer_desc(desc);
+	nr_pages = __calc_nr_pages_ring_buffer_desc(buffer_size);
 
 	for_each_cpu(cpu, cpumask) {
 		unsigned int id;