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, 140 insertions, 0 deletions

diff --git a/scripts/gcc-plugins/gcc-generate-rtl-pass.h b/scripts/gcc-plugins/gcc-generate-rtl-pass.h
new file mode 100644
index 000000000..7cd46e8d5
--- /dev/null
+++ b/scripts/gcc-plugins/gcc-generate-rtl-pass.h
@@ -0,0 +1,140 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Generator for RTL pass related boilerplate code/data
+ *
+ * Supports gcc 4.5-6
+ *
+ * Usage:
+ *
+ * 1. before inclusion define PASS_NAME
+ * 2. before inclusion define NO_* for unimplemented callbacks
+ *    NO_GATE
+ *    NO_EXECUTE
+ * 3. before inclusion define PROPERTIES_* and TODO_FLAGS_* to override
+ *    the default 0 values
+ * 4. for convenience, all the above will be undefined after inclusion!
+ * 5. the only exported name is make_PASS_NAME_pass() to register with gcc
+ */
+
+#ifndef PASS_NAME
+#error at least PASS_NAME must be defined
+#else
+#define __GCC_PLUGIN_STRINGIFY(n)	#n
+#define _GCC_PLUGIN_STRINGIFY(n)	__GCC_PLUGIN_STRINGIFY(n)
+#define _GCC_PLUGIN_CONCAT2(x, y)	x ## y
+#define _GCC_PLUGIN_CONCAT3(x, y, z)	x ## y ## z
+
+#define __PASS_NAME_PASS_DATA(n)	_GCC_PLUGIN_CONCAT2(n, _pass_data)
+#define _PASS_NAME_PASS_DATA		__PASS_NAME_PASS_DATA(PASS_NAME)
+
+#define __PASS_NAME_PASS(n)		_GCC_PLUGIN_CONCAT2(n, _pass)
+#define _PASS_NAME_PASS			__PASS_NAME_PASS(PASS_NAME)
+
+#define _PASS_NAME_NAME			_GCC_PLUGIN_STRINGIFY(PASS_NAME)
+
+#define __MAKE_PASS_NAME_PASS(n)	_GCC_PLUGIN_CONCAT3(make_, n, _pass)
+#define _MAKE_PASS_NAME_PASS		__MAKE_PASS_NAME_PASS(PASS_NAME)
+
+#ifdef NO_GATE
+#define _GATE NULL
+#define _HAS_GATE false
+#else
+#define __GATE(n)			_GCC_PLUGIN_CONCAT2(n, _gate)
+#define _GATE				__GATE(PASS_NAME)
+#define _HAS_GATE true
+#endif
+
+#ifdef NO_EXECUTE
+#define _EXECUTE NULL
+#define _HAS_EXECUTE false
+#else
+#define __EXECUTE(n)			_GCC_PLUGIN_CONCAT2(n, _execute)
+#define _EXECUTE			__EXECUTE(PASS_NAME)
+#define _HAS_EXECUTE true
+#endif
+
+#ifndef PROPERTIES_REQUIRED
+#define PROPERTIES_REQUIRED 0
+#endif
+
+#ifndef PROPERTIES_PROVIDED
+#define PROPERTIES_PROVIDED 0
+#endif
+
+#ifndef PROPERTIES_DESTROYED
+#define PROPERTIES_DESTROYED 0
+#endif
+
+#ifndef TODO_FLAGS_START
+#define TODO_FLAGS_START 0
+#endif
+
+#ifndef TODO_FLAGS_FINISH
+#define TODO_FLAGS_FINISH 0
+#endif
+
+namespace {
+static const pass_data _PASS_NAME_PASS_DATA = {
+		.type			= RTL_PASS,
+		.name			= _PASS_NAME_NAME,
+		.optinfo_flags		= OPTGROUP_NONE,
+		.tv_id			= TV_NONE,
+		.properties_required	= PROPERTIES_REQUIRED,
+		.properties_provided	= PROPERTIES_PROVIDED,
+		.properties_destroyed	= PROPERTIES_DESTROYED,
+		.todo_flags_start	= TODO_FLAGS_START,
+		.todo_flags_finish	= TODO_FLAGS_FINISH,
+};
+
+class _PASS_NAME_PASS : public rtl_opt_pass {
+public:
+	_PASS_NAME_PASS() : rtl_opt_pass(_PASS_NAME_PASS_DATA, g) {}
+
+#ifndef NO_GATE
+	virtual bool gate(function *) { return _GATE(); }
+#endif
+
+	virtual opt_pass *clone() { return new _PASS_NAME_PASS(); }
+
+#ifndef NO_EXECUTE
+	virtual unsigned int execute(function *) { return _EXECUTE(); }
+#endif
+};
+}
+
+opt_pass *_MAKE_PASS_NAME_PASS(void)
+{
+	return new _PASS_NAME_PASS();
+}
+
+/* clean up user provided defines */
+#undef PASS_NAME
+#undef NO_GATE
+#undef NO_EXECUTE
+
+#undef PROPERTIES_DESTROYED
+#undef PROPERTIES_PROVIDED
+#undef PROPERTIES_REQUIRED
+#undef TODO_FLAGS_FINISH
+#undef TODO_FLAGS_START
+
+/* clean up generated defines */
+#undef _EXECUTE
+#undef __EXECUTE
+#undef _GATE
+#undef __GATE
+#undef _GCC_PLUGIN_CONCAT2
+#undef _GCC_PLUGIN_CONCAT3
+#undef _GCC_PLUGIN_STRINGIFY
+#undef __GCC_PLUGIN_STRINGIFY
+#undef _HAS_EXECUTE
+#undef _HAS_GATE
+#undef _MAKE_PASS_NAME_PASS
+#undef __MAKE_PASS_NAME_PASS
+#undef _PASS_NAME_NAME
+#undef _PASS_NAME_PASS
+#undef __PASS_NAME_PASS
+#undef _PASS_NAME_PASS_DATA
+#undef __PASS_NAME_PASS_DATA
+
+#endif /* PASS_NAME */