Merge tag 'trace-v6.17-rc2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Fix rtla and latency tooling pkg-config errors

   If libtraceevent and libtracefs is installed, but their corresponding
   '.pc' files are not installed, it reports that the libraries are
   missing and confuses the developer. Instead, report that the
   pkg-config files are missing and should be installed.

 - Fix overflow bug of the parser in trace_get_user()

   trace_get_user() uses the parsing functions to parse the user space
   strings. If the parser fails due to incorrect processing, it doesn't
   terminate the buffer with a nul byte. Add a "failed" flag to the
   parser that gets set when parsing fails and is used to know if the
   buffer is fine to use or not.

 - Remove a semicolon that was at an end of a comment line

 - Fix register_ftrace_graph() to unregister the pm notifier on error

   The register_ftrace_graph() registers a pm notifier but there's an
   error path that can exit the function without unregistering it. Since
   the function returns an error, it will never be unregistered.

 - Allocate and copy ftrace hash for reader of ftrace filter files

   When the set_ftrace_filter or set_ftrace_notrace files are open for
   read, an iterator is created and sets its hash pointer to the
   associated hash that represents filtering or notrace filtering to it.
   The issue is that the hash it points to can change while the
   iteration is happening. All the locking used to access the tracer's
   hashes are released which means those hashes can change or even be
   freed. Using the hash pointed to by the iterator can cause UAF bugs
   or similar.

   Have the read of these files allocate and copy the corresponding
   hashes and use that as that will keep them the same while the
   iterator is open. This also simplifies the code as opening it for
   write already does an allocate and copy, and now that the read is
   doing the same, there's no need to check which way it was opened on
   the release of the file, and the iterator hash can always be freed.

 - Fix function graph to copy args into temp storage

   The output of the function graph tracer shows both the entry and the
   exit of a function. When the exit is right after the entry, it
   combines the two events into one with the output of "function();",
   instead of showing:

     function() {
     }

   In order to do this, the iterator descriptor that reads the events
   includes storage that saves the entry event while it peaks at the
   next event in the ring buffer. The peek can free the entry event so
   the iterator must store the information to use it after the peek.

   With the addition of function graph tracer recording the args, where
   the args are a dynamic array in the entry event, the temp storage
   does not save them. This causes the args to be corrupted or even
   cause a read of unsafe memory.

   Add space to save the args in the temp storage of the iterator.

 - Fix race between ftrace_dump and reading trace_pipe

   ftrace_dump() is used when a crash occurs where the ftrace buffer
   will be printed to the console. But it can also be triggered by
   sysrq-z. If a sysrq-z is triggered while a task is reading trace_pipe
   it can cause a race in the ftrace_dump() where it checks if the
   buffer has content, then it checks if the next event is available,
   and then prints the output (regardless if the next event was
   available or not). Reading trace_pipe at the same time can cause it
   to not be available, and this triggers a WARN_ON in the print. Move
   the printing into the check if the next event exists or not

* tag 'trace-v6.17-rc2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ftrace: Also allocate and copy hash for reading of filter files
  ftrace: Fix potential warning in trace_printk_seq during ftrace_dump
  fgraph: Copy args in intermediate storage with entry
  trace/fgraph: Fix the warning caused by missing unregister notifier
  ring-buffer: Remove redundant semicolons
  tracing: Limit access to parser->buffer when trace_get_user failed
  rtla: Check pkg-config install
  tools/latency-collector: Check pkg-config install

Author: torvalds

kernel/trace/fgraph.c

@@ -1397,6 +1397,7 @@ int register_ftrace_graph(struct fgraph_ops *gops)
 		ftrace_graph_active--;
 		gops->saved_func = NULL;
 		fgraph_lru_release_index(i);
+		unregister_pm_notifier(&ftrace_suspend_notifier);
 	}
 	return ret;
 }

kernel/trace/ftrace.c

@@ -4661,13 +4661,17 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
 	        } else {
 			iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
 		}
+	} else {
+		if (hash)
+			iter->hash = alloc_and_copy_ftrace_hash(hash->size_bits, hash);
+		else
+			iter->hash = EMPTY_HASH;
+	}
 
-		if (!iter->hash) {
-			trace_parser_put(&iter->parser);
-			goto out_unlock;
-		}
-	} else
-		iter->hash = hash;
+	if (!iter->hash) {
+		trace_parser_put(&iter->parser);
+		goto out_unlock;
+	}
 
 	ret = 0;
 
@@ -6543,9 +6547,6 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
 		ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
 						      iter->hash, filter_hash);
 		mutex_unlock(&ftrace_lock);
-	} else {
-		/* For read only, the hash is the ops hash */
-		iter->hash = NULL;
 	}
 
 	mutex_unlock(&iter->ops->func_hash->regex_lock);

kernel/trace/ring_buffer.c

@@ -7666,7 +7666,7 @@ static __init int test_ringbuffer(void)
 	rb_test_started = true;
 
 	set_current_state(TASK_INTERRUPTIBLE);
-	/* Just run for 10 seconds */;
+	/* Just run for 10 seconds */
 	schedule_timeout(10 * HZ);
 
 	kthread_stop(rb_hammer);

kernel/trace/trace.c

@@ -1816,7 +1816,7 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
 
 	ret = get_user(ch, ubuf++);
 	if (ret)
-		return ret;
+		goto fail;
 
 	read++;
 	cnt--;
@@ -1830,7 +1830,7 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
 		while (cnt && isspace(ch)) {
 			ret = get_user(ch, ubuf++);
 			if (ret)
-				return ret;
+				goto fail;
 			read++;
 			cnt--;
 		}
@@ -1848,12 +1848,14 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
 	while (cnt && !isspace(ch) && ch) {
 		if (parser->idx < parser->size - 1)
 			parser->buffer[parser->idx++] = ch;
-		else
-			return -EINVAL;
+		else {
+			ret = -EINVAL;
+			goto fail;
+		}
 
 		ret = get_user(ch, ubuf++);
 		if (ret)
-			return ret;
+			goto fail;
 		read++;
 		cnt--;
 	}
@@ -1868,11 +1870,15 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
 		/* Make sure the parsed string always terminates with '\0'. */
 		parser->buffer[parser->idx] = 0;
 	} else {
-		return -EINVAL;
+		ret = -EINVAL;
+		goto fail;
 	}
 
 	*ppos += read;
 	return read;
+fail:
+	trace_parser_fail(parser);
+	return ret;
 }
 
 /* TODO add a seq_buf_to_buffer() */
@@ -10632,10 +10638,10 @@ static void ftrace_dump_one(struct trace_array *tr, enum ftrace_dump_mode dump_m
 			ret = print_trace_line(&iter);
 			if (ret != TRACE_TYPE_NO_CONSUME)
 				trace_consume(&iter);
+
+			trace_printk_seq(&iter.seq);
 		}
 		touch_nmi_watchdog();
-
-		trace_printk_seq(&iter.seq);
 	}
 
 	if (!cnt)

kernel/trace/trace.h

@@ -1292,14 +1292,15 @@ bool ftrace_event_is_function(struct trace_event_call *call);
  */
 struct trace_parser {
 	bool		cont;
+	bool		fail;
 	char		*buffer;
 	unsigned	idx;
 	unsigned	size;
 };
 
 static inline bool trace_parser_loaded(struct trace_parser *parser)
 {
-	return (parser->idx != 0);
+	return !parser->fail && parser->idx != 0;
 }
 
 static inline bool trace_parser_cont(struct trace_parser *parser)
@@ -1313,6 +1314,11 @@ static inline void trace_parser_clear(struct trace_parser *parser)
 	parser->idx = 0;
 }
 
+static inline void trace_parser_fail(struct trace_parser *parser)
+{
+	parser->fail = true;
+}
+
 extern int trace_parser_get_init(struct trace_parser *parser, int size);
 extern void trace_parser_put(struct trace_parser *parser);
 extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf,

kernel/trace/trace_functions_graph.c

@@ -27,14 +27,21 @@ struct fgraph_cpu_data {
 	unsigned long	enter_funcs[FTRACE_RETFUNC_DEPTH];
 };
 
+struct fgraph_ent_args {
+	struct ftrace_graph_ent_entry	ent;
+	/* Force the sizeof of args[] to have FTRACE_REGS_MAX_ARGS entries */
+	unsigned long			args[FTRACE_REGS_MAX_ARGS];
+};
+
 struct fgraph_data {
 	struct fgraph_cpu_data __percpu *cpu_data;
 
 	/* Place to preserve last processed entry. */
 	union {
-		struct ftrace_graph_ent_entry	ent;
+		struct fgraph_ent_args		ent;
+		/* TODO allow retaddr to have args */
 		struct fgraph_retaddr_ent_entry	rent;
-	} ent;
+	};
 	struct ftrace_graph_ret_entry	ret;
 	int				failed;
 	int				cpu;
@@ -627,10 +634,13 @@ get_return_for_leaf(struct trace_iterator *iter,
 			 * Save current and next entries for later reference
 			 * if the output fails.
 			 */
-			if (unlikely(curr->ent.type == TRACE_GRAPH_RETADDR_ENT))
-				data->ent.rent = *(struct fgraph_retaddr_ent_entry *)curr;
-			else
-				data->ent.ent = *curr;
+			if (unlikely(curr->ent.type == TRACE_GRAPH_RETADDR_ENT)) {
+				data->rent = *(struct fgraph_retaddr_ent_entry *)curr;
+			} else {
+				int size = min((int)sizeof(data->ent), (int)iter->ent_size);
+
+				memcpy(&data->ent, curr, size);
+			}
 			/*
 			 * If the next event is not a return type, then
 			 * we only care about what type it is. Otherwise we can

tools/tracing/latency/Makefile.config

@@ -1,7 +1,15 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
+include $(srctree)/tools/scripts/utilities.mak
+
 STOP_ERROR :=
 
+ifndef ($(NO_LIBTRACEEVENT),1)
+  ifeq ($(call get-executable,$(PKG_CONFIG)),)
+    $(error Error: $(PKG_CONFIG) needed by libtraceevent/libtracefs is missing on this system, please install it)
+  endif
+endif
+
 define lib_setup
   $(eval LIB_INCLUDES += $(shell sh -c "$(PKG_CONFIG) --cflags lib$(1)"))
   $(eval LDFLAGS += $(shell sh -c "$(PKG_CONFIG) --libs-only-L lib$(1)"))

tools/tracing/rtla/Makefile.config

@@ -1,10 +1,18 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
+include $(srctree)/tools/scripts/utilities.mak
+
 STOP_ERROR :=
 
 LIBTRACEEVENT_MIN_VERSION = 1.5
 LIBTRACEFS_MIN_VERSION = 1.6
 
+ifndef ($(NO_LIBTRACEEVENT),1)
+  ifeq ($(call get-executable,$(PKG_CONFIG)),)
+    $(error Error: $(PKG_CONFIG) needed by libtraceevent/libtracefs is missing on this system, please install it)
+  endif
+endif
+
 define lib_setup
   $(eval LIB_INCLUDES += $(shell sh -c "$(PKG_CONFIG) --cflags lib$(1)"))
   $(eval LDFLAGS += $(shell sh -c "$(PKG_CONFIG) --libs-only-L lib$(1)"))