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

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
  ...

1 files changed, 586 insertions, 0 deletions

diff --git a/lib/tests/stackinit_kunit.c b/lib/tests/stackinit_kunit.c
new file mode 100644
index 000000000..ff2784769
--- /dev/null
+++ b/lib/tests/stackinit_kunit.c
@@ -0,0 +1,586 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Test cases for compiler-based stack variable zeroing via
+ * -ftrivial-auto-var-init={zero,pattern}.
+ * For example, see:
+ * "Running tests with kunit_tool" at Documentation/dev-tools/kunit/start.rst
+ *	./tools/testing/kunit/kunit.py run stackinit [--raw_output] \
+ *		--make_option LLVM=1 \
+ *		--kconfig_add CONFIG_INIT_STACK_ALL_ZERO=y
+ *
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <kunit/test.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h>
+
+/* Exfiltration buffer. */
+#define MAX_VAR_SIZE	128
+static u8 check_buf[MAX_VAR_SIZE];
+
+/* Character array to trigger stack protector in all functions. */
+#define VAR_BUFFER	 32
+
+/* Volatile mask to convince compiler to copy memory with 0xff. */
+static volatile u8 forced_mask = 0xff;
+
+/* Location and size tracking to validate fill and test are colocated. */
+static void *fill_start, *target_start;
+static size_t fill_size, target_size;
+
+static bool stackinit_range_contains(char *haystack_start, size_t haystack_size,
+				     char *needle_start, size_t needle_size)
+{
+	if (needle_start >= haystack_start &&
+	    needle_start + needle_size <= haystack_start + haystack_size)
+		return true;
+	return false;
+}
+
+/* Whether the test is expected to fail. */
+#define WANT_SUCCESS				0
+#define XFAIL					1
+
+#define DO_NOTHING_TYPE_SCALAR(var_type)	var_type
+#define DO_NOTHING_TYPE_STRING(var_type)	void
+#define DO_NOTHING_TYPE_STRUCT(var_type)	void
+#define DO_NOTHING_TYPE_UNION(var_type)		void
+
+#define DO_NOTHING_RETURN_SCALAR(ptr)		*(ptr)
+#define DO_NOTHING_RETURN_STRING(ptr)		/**/
+#define DO_NOTHING_RETURN_STRUCT(ptr)		/**/
+#define DO_NOTHING_RETURN_UNION(ptr)		/**/
+
+#define DO_NOTHING_CALL_SCALAR(var, name)			\
+		(var) = do_nothing_ ## name(&(var))
+#define DO_NOTHING_CALL_STRING(var, name)			\
+		do_nothing_ ## name(var)
+#define DO_NOTHING_CALL_STRUCT(var, name)			\
+		do_nothing_ ## name(&(var))
+#define DO_NOTHING_CALL_UNION(var, name)			\
+		do_nothing_ ## name(&(var))
+
+#define FETCH_ARG_SCALAR(var)		&var
+#define FETCH_ARG_STRING(var)		var
+#define FETCH_ARG_STRUCT(var)		&var
+#define FETCH_ARG_UNION(var)		&var
+
+/*
+ * On m68k, if the leaf function test variable is longer than 8 bytes,
+ * the start of the stack frame moves. 8 is sufficiently large to
+ * test m68k char arrays, but leave it at 16 for other architectures.
+ */
+#ifdef CONFIG_M68K
+#define FILL_SIZE_STRING		8
+#define FILL_SIZE_ARRAY			2
+#else
+#define FILL_SIZE_STRING		16
+#define FILL_SIZE_ARRAY			8
+#endif
+
+#define INIT_CLONE_SCALAR		/**/
+#define INIT_CLONE_STRING		[FILL_SIZE_STRING]
+#define INIT_CLONE_STRUCT		/**/
+#define INIT_CLONE_UNION		/**/
+
+#define ZERO_CLONE_SCALAR(zero)		memset(&(zero), 0x00, sizeof(zero))
+#define ZERO_CLONE_STRING(zero)		memset(&(zero), 0x00, sizeof(zero))
+/*
+ * For the struct, intentionally poison padding to see if it gets
+ * copied out in direct assignments.
+ * */
+#define ZERO_CLONE_STRUCT(zero)				\
+	do {						\
+		memset(&(zero), 0xFF, sizeof(zero));	\
+		zero.one = 0;				\
+		zero.two = 0;				\
+		zero.three = 0;				\
+		zero.four = 0;				\
+	} while (0)
+#define ZERO_CLONE_UNION(zero)		ZERO_CLONE_STRUCT(zero)
+
+#define INIT_SCALAR_none(var_type)	/**/
+#define INIT_SCALAR_zero(var_type)	= 0
+
+#define INIT_STRING_none(var_type)	[FILL_SIZE_STRING] /**/
+#define INIT_STRING_zero(var_type)	[FILL_SIZE_STRING] = { }
+
+#define INIT_STRUCT_none(var_type)	/**/
+#define INIT_STRUCT_zero(var_type)	= { }
+#define INIT_STRUCT_old_zero(var_type)	= { 0 }
+
+
+#define __static_partial		{ .two = 0, }
+#define __static_all			{ .one = 0,			\
+					  .two = 0,			\
+					  .three = 0,			\
+					  .four = 0,			\
+					}
+#define __dynamic_partial		{ .two = arg->two, }
+#define __dynamic_all			{ .one = arg->one,		\
+					  .two = arg->two,		\
+					  .three = arg->three,		\
+					  .four = arg->four,		\
+					}
+#define __runtime_partial		var.two = 0
+#define __runtime_all			var.one = 0;			\
+					var.two = 0;			\
+					var.three = 0;			\
+					var.four = 0
+
+#define INIT_STRUCT_static_partial(var_type)				\
+					= __static_partial
+#define INIT_STRUCT_static_all(var_type)				\
+					= __static_all
+#define INIT_STRUCT_dynamic_partial(var_type)				\
+					= __dynamic_partial
+#define INIT_STRUCT_dynamic_all(var_type)				\
+					= __dynamic_all
+#define INIT_STRUCT_runtime_partial(var_type)				\
+					; __runtime_partial
+#define INIT_STRUCT_runtime_all(var_type)				\
+					; __runtime_all
+
+#define INIT_STRUCT_assigned_static_partial(var_type)			\
+					; var = (var_type)__static_partial
+#define INIT_STRUCT_assigned_static_all(var_type)			\
+					; var = (var_type)__static_all
+#define INIT_STRUCT_assigned_dynamic_partial(var_type)			\
+					; var = (var_type)__dynamic_partial
+#define INIT_STRUCT_assigned_dynamic_all(var_type)			\
+					; var = (var_type)__dynamic_all
+
+#define INIT_STRUCT_assigned_copy(var_type)				\
+					; var = *(arg)
+
+/* Union initialization is the same as structs. */
+#define INIT_UNION_none(var_type)	INIT_STRUCT_none(var_type)
+#define INIT_UNION_zero(var_type)	INIT_STRUCT_zero(var_type)
+#define INIT_UNION_old_zero(var_type)	INIT_STRUCT_old_zero(var_type)
+
+#define INIT_UNION_static_partial(var_type)		\
+	INIT_STRUCT_static_partial(var_type)
+#define INIT_UNION_static_all(var_type)			\
+	INIT_STRUCT_static_all(var_type)
+#define INIT_UNION_dynamic_partial(var_type)		\
+	INIT_STRUCT_dynamic_partial(var_type)
+#define INIT_UNION_dynamic_all(var_type)		\
+	INIT_STRUCT_dynamic_all(var_type)
+#define INIT_UNION_runtime_partial(var_type)		\
+	INIT_STRUCT_runtime_partial(var_type)
+#define INIT_UNION_runtime_all(var_type)		\
+	INIT_STRUCT_runtime_all(var_type)
+#define INIT_UNION_assigned_static_partial(var_type)	\
+	INIT_STRUCT_assigned_static_partial(var_type)
+#define INIT_UNION_assigned_static_all(var_type)	\
+	INIT_STRUCT_assigned_static_all(var_type)
+#define INIT_UNION_assigned_dynamic_partial(var_type)	\
+	INIT_STRUCT_assigned_dynamic_partial(var_type)
+#define INIT_UNION_assigned_dynamic_all(var_type)	\
+	INIT_STRUCT_assigned_dynamic_all(var_type)
+#define INIT_UNION_assigned_copy(var_type)		\
+	INIT_STRUCT_assigned_copy(var_type)
+
+/*
+ * The "did we actually fill the stack?" check value needs
+ * to be neither 0 nor any of the "pattern" bytes. The
+ * pattern bytes are compiler, architecture, and type based,
+ * so we have to pick a value that never appears for those
+ * combinations. Use 0x99 which is not 0xFF, 0xFE, nor 0xAA.
+ */
+#define FILL_BYTE	0x99
+
+/*
+ * @name: unique string name for the test
+ * @var_type: type to be tested for zeroing initialization
+ * @which: is this a SCALAR, STRING, or STRUCT type?
+ * @init_level: what kind of initialization is performed
+ * @xfail: is this test expected to fail?
+ */
+#define DEFINE_TEST_DRIVER(name, var_type, which, xfail)	\
+/* Returns 0 on success, 1 on failure. */			\
+static noinline void test_ ## name (struct kunit *test)		\
+{								\
+	var_type zero INIT_CLONE_ ## which;			\
+	int ignored;						\
+	u8 sum = 0, i;						\
+								\
+	/* Notice when a new test is larger than expected. */	\
+	BUILD_BUG_ON(sizeof(zero) > MAX_VAR_SIZE);		\
+								\
+	/* Fill clone type with zero for per-field init. */	\
+	ZERO_CLONE_ ## which(zero);				\
+	/* Clear entire check buffer for 0xFF overlap test. */	\
+	memset(check_buf, 0x00, sizeof(check_buf));		\
+	/* Fill stack with FILL_BYTE. */			\
+	ignored = leaf_ ##name((unsigned long)&ignored, 1,	\
+				FETCH_ARG_ ## which(zero));	\
+	/* Verify all bytes overwritten with FILL_BYTE. */	\
+	for (sum = 0, i = 0; i < target_size; i++)		\
+		sum += (check_buf[i] != FILL_BYTE);		\
+	/* Clear entire check buffer for later bit tests. */	\
+	memset(check_buf, 0x00, sizeof(check_buf));		\
+	/* Extract stack-defined variable contents. */		\
+	ignored = leaf_ ##name((unsigned long)&ignored, 0,	\
+				FETCH_ARG_ ## which(zero));	\
+	/*							\
+	 * Delay the sum test to here to do as little as	\
+	 * possible between the two leaf function calls.	\
+	 */							\
+	KUNIT_ASSERT_EQ_MSG(test, sum, 0,			\
+			    "leaf fill was not 0x%02X!?\n",	\
+			    FILL_BYTE);				\
+								\
+	/* Validate that compiler lined up fill and target. */	\
+	KUNIT_ASSERT_TRUE_MSG(test,				\
+		stackinit_range_contains(fill_start, fill_size,	\
+			    target_start, target_size),		\
+		"stackframe was not the same between calls!? "	\
+		"(fill %zu wide, target offset by %d)\n",	\
+		fill_size,					\
+		(int)((ssize_t)(uintptr_t)fill_start -		\
+		      (ssize_t)(uintptr_t)target_start));	\
+								\
+	/* Validate check region has no FILL_BYTE bytes. */	\
+	for (sum = 0, i = 0; i < target_size; i++)		\
+		sum += (check_buf[i] == FILL_BYTE);		\
+								\
+	if (sum != 0 && xfail)					\
+		kunit_skip(test,				\
+			   "XFAIL uninit bytes: %d\n",		\
+			   sum);				\
+	KUNIT_ASSERT_EQ_MSG(test, sum, 0,			\
+		"uninit bytes: %d\n", sum);			\
+}
+#define DEFINE_TEST(name, var_type, which, init_level, xfail)	\
+/* no-op to force compiler into ignoring "uninitialized" vars */\
+static noinline DO_NOTHING_TYPE_ ## which(var_type)		\
+do_nothing_ ## name(var_type *ptr)				\
+{								\
+	OPTIMIZER_HIDE_VAR(ptr);				\
+	/* Will always be true, but compiler doesn't know. */	\
+	if ((unsigned long)ptr > 0x2)				\
+		return DO_NOTHING_RETURN_ ## which(ptr);	\
+	else							\
+		return DO_NOTHING_RETURN_ ## which(ptr + 1);	\
+}								\
+static noinline int leaf_ ## name(unsigned long sp, bool fill,	\
+				  var_type *arg)		\
+{								\
+	char buf[VAR_BUFFER];					\
+	var_type var						\
+		INIT_ ## which ## _ ## init_level(var_type);	\
+								\
+	target_start = &var;					\
+	target_size = sizeof(var);				\
+	/*							\
+	 * Keep this buffer around to make sure we've got a	\
+	 * stack frame of SOME kind...				\
+	 */							\
+	memset(buf, (char)(sp & 0xff), sizeof(buf));		\
+	/* Fill variable with FILL_BYTE. */			\
+	if (fill) {						\
+		fill_start = &var;				\
+		fill_size = sizeof(var);			\
+		memset(fill_start,				\
+		       FILL_BYTE & forced_mask,			\
+		       fill_size);				\
+	}							\
+								\
+	/* Silence "never initialized" warnings. */		\
+	DO_NOTHING_CALL_ ## which(var, name);			\
+								\
+	/* Exfiltrate "var". */					\
+	memcpy(check_buf, target_start, target_size);		\
+								\
+	return (int)buf[0] | (int)buf[sizeof(buf) - 1];		\
+}								\
+DEFINE_TEST_DRIVER(name, var_type, which, xfail)
+
+/* Structure with no padding. */
+struct test_packed {
+	unsigned long one;
+	unsigned long two;
+	unsigned long three;
+	unsigned long four;
+};
+
+/* Simple structure with padding likely to be covered by compiler. */
+struct test_small_hole {
+	size_t one;
+	char two;
+	/* 3 byte padding hole here. */
+	int three;
+	unsigned long four;
+};
+
+/* Trigger unhandled padding in a structure. */
+struct test_big_hole {
+	u8 one;
+	u8 two;
+	u8 three;
+	/* 61 byte padding hole here. */
+	u8 four __aligned(64);
+} __aligned(64);
+
+struct test_trailing_hole {
+	char *one;
+	char *two;
+	char *three;
+	char four;
+	/* "sizeof(unsigned long) - 1" byte padding hole here. */
+};
+
+/* Test if STRUCTLEAK is clearing structs with __user fields. */
+struct test_user {
+	u8 one;
+	unsigned long two;
+	char __user *three;
+	unsigned long four;
+};
+
+/* No padding: all members are the same size. */
+union test_same_sizes {
+	unsigned long one;
+	unsigned long two;
+	unsigned long three;
+	unsigned long four;
+};
+
+/* Mismatched sizes, with one and two being small */
+union test_small_start {
+	char one:1;
+	char two;
+	short three;
+	unsigned long four;
+	struct big_struct {
+		unsigned long array[FILL_SIZE_ARRAY];
+	} big;
+};
+
+/* Mismatched sizes, with three and four being small */
+union test_small_end {
+	short one;
+	unsigned long two;
+	char three:1;
+	char four;
+};
+
+#define ALWAYS_PASS	WANT_SUCCESS
+#define ALWAYS_FAIL	XFAIL
+
+#ifdef CONFIG_INIT_STACK_NONE
+# define USER_PASS	XFAIL
+# define BYREF_PASS	XFAIL
+# define STRONG_PASS	XFAIL
+#else
+# define USER_PASS	WANT_SUCCESS
+# define BYREF_PASS	WANT_SUCCESS
+# define STRONG_PASS	WANT_SUCCESS
+#endif
+
+#define DEFINE_SCALAR_TEST(name, init, xfail)			\
+		DEFINE_TEST(name ## _ ## init, name, SCALAR,	\
+			    init, xfail)
+
+#define DEFINE_SCALAR_TESTS(init, xfail)			\
+		DEFINE_SCALAR_TEST(u8, init, xfail);		\
+		DEFINE_SCALAR_TEST(u16, init, xfail);		\
+		DEFINE_SCALAR_TEST(u32, init, xfail);		\
+		DEFINE_SCALAR_TEST(u64, init, xfail);		\
+		DEFINE_TEST(char_array_ ## init, unsigned char,	\
+			    STRING, init, xfail)
+
+#define DEFINE_STRUCT_TEST(name, init, xfail)			\
+		DEFINE_TEST(name ## _ ## init,			\
+			    struct test_ ## name, STRUCT, init, \
+			    xfail)
+
+#define DEFINE_UNION_TEST(name, init, xfail)			\
+		DEFINE_TEST(name ## _ ## init,			\
+			    union test_ ## name, STRUCT, init,	\
+			    xfail)
+
+#define DEFINE_STRUCT_TESTS(init, xfail)			\
+		DEFINE_STRUCT_TEST(small_hole, init, xfail);	\
+		DEFINE_STRUCT_TEST(big_hole, init, xfail);	\
+		DEFINE_STRUCT_TEST(trailing_hole, init, xfail);	\
+		DEFINE_STRUCT_TEST(packed, init, xfail)
+
+#define DEFINE_STRUCT_INITIALIZER_TESTS(base, xfail)		\
+		DEFINE_STRUCT_TESTS(base ## _ ## partial,	\
+				    xfail);			\
+		DEFINE_STRUCT_TESTS(base ## _ ## all, xfail)
+
+#define DEFINE_UNION_INITIALIZER_TESTS(base, xfail)		\
+		DEFINE_UNION_TESTS(base ## _ ## partial,	\
+				    xfail);			\
+		DEFINE_UNION_TESTS(base ## _ ## all, xfail)
+
+#define DEFINE_UNION_TESTS(init, xfail)				\
+		DEFINE_UNION_TEST(same_sizes, init, xfail);	\
+		DEFINE_UNION_TEST(small_start, init, xfail);	\
+		DEFINE_UNION_TEST(small_end, init, xfail);
+
+/* These should be fully initialized all the time! */
+DEFINE_SCALAR_TESTS(zero, ALWAYS_PASS);
+DEFINE_STRUCT_TESTS(zero, ALWAYS_PASS);
+DEFINE_STRUCT_TESTS(old_zero, ALWAYS_PASS);
+DEFINE_UNION_TESTS(zero, ALWAYS_PASS);
+DEFINE_UNION_TESTS(old_zero, ALWAYS_PASS);
+/* Struct initializers: padding may be left uninitialized. */
+DEFINE_STRUCT_INITIALIZER_TESTS(static, STRONG_PASS);
+DEFINE_STRUCT_INITIALIZER_TESTS(dynamic, STRONG_PASS);
+DEFINE_STRUCT_INITIALIZER_TESTS(runtime, STRONG_PASS);
+DEFINE_STRUCT_INITIALIZER_TESTS(assigned_static, STRONG_PASS);
+DEFINE_STRUCT_INITIALIZER_TESTS(assigned_dynamic, STRONG_PASS);
+DEFINE_STRUCT_TESTS(assigned_copy, ALWAYS_FAIL);
+DEFINE_UNION_INITIALIZER_TESTS(static, STRONG_PASS);
+DEFINE_UNION_INITIALIZER_TESTS(dynamic, STRONG_PASS);
+DEFINE_UNION_INITIALIZER_TESTS(runtime, STRONG_PASS);
+DEFINE_UNION_INITIALIZER_TESTS(assigned_static, STRONG_PASS);
+DEFINE_UNION_INITIALIZER_TESTS(assigned_dynamic, STRONG_PASS);
+DEFINE_UNION_TESTS(assigned_copy, ALWAYS_FAIL);
+/* No initialization without compiler instrumentation. */
+DEFINE_SCALAR_TESTS(none, STRONG_PASS);
+DEFINE_STRUCT_TESTS(none, BYREF_PASS);
+/* Initialization of members with __user attribute. */
+DEFINE_TEST(user, struct test_user, STRUCT, none, USER_PASS);
+
+/*
+ * Check two uses through a variable declaration outside either path,
+ * which was noticed as a special case in porting earlier stack init
+ * compiler logic.
+ */
+static int noinline __leaf_switch_none(int path, bool fill)
+{
+	switch (path) {
+		/*
+		 * This is intentionally unreachable. To silence the
+		 * warning, build with -Wno-switch-unreachable
+		 */
+		uint64_t var[10];
+
+	case 1:
+		target_start = &var;
+		target_size = sizeof(var);
+		if (fill) {
+			fill_start = &var;
+			fill_size = sizeof(var);
+
+			memset(fill_start, (forced_mask | 0x55) & FILL_BYTE, fill_size);
+		}
+		memcpy(check_buf, target_start, target_size);
+		break;
+	case 2:
+		target_start = &var;
+		target_size = sizeof(var);
+		if (fill) {
+			fill_start = &var;
+			fill_size = sizeof(var);
+
+			memset(fill_start, (forced_mask | 0xaa) & FILL_BYTE, fill_size);
+		}
+		memcpy(check_buf, target_start, target_size);
+		break;
+	default:
+		var[1] = 5;
+		return var[1] & forced_mask;
+	}
+	return 0;
+}
+
+static noinline int leaf_switch_1_none(unsigned long sp, bool fill,
+					      uint64_t *arg)
+{
+	return __leaf_switch_none(1, fill);
+}
+
+static noinline int leaf_switch_2_none(unsigned long sp, bool fill,
+					      uint64_t *arg)
+{
+	return __leaf_switch_none(2, fill);
+}
+
+/*
+ * These are expected to fail for most configurations because neither
+ * GCC nor Clang have a way to perform initialization of variables in
+ * non-code areas (i.e. in a switch statement before the first "case").
+ * https://llvm.org/pr44916
+ */
+DEFINE_TEST_DRIVER(switch_1_none, uint64_t, SCALAR, ALWAYS_FAIL);
+DEFINE_TEST_DRIVER(switch_2_none, uint64_t, SCALAR, ALWAYS_FAIL);
+
+#define KUNIT_test_scalars(init)			\
+		KUNIT_CASE(test_u8_ ## init),		\
+		KUNIT_CASE(test_u16_ ## init),		\
+		KUNIT_CASE(test_u32_ ## init),		\
+		KUNIT_CASE(test_u64_ ## init),		\
+		KUNIT_CASE(test_char_array_ ## init)
+
+#define KUNIT_test_structs(init)			\
+		KUNIT_CASE(test_small_hole_ ## init),	\
+		KUNIT_CASE(test_big_hole_ ## init),	\
+		KUNIT_CASE(test_trailing_hole_ ## init),\
+		KUNIT_CASE(test_packed_ ## init)	\
+
+#define KUNIT_test_unions(init)				\
+		KUNIT_CASE(test_same_sizes_ ## init),	\
+		KUNIT_CASE(test_small_start_ ## init),	\
+		KUNIT_CASE(test_small_end_ ## init)	\
+
+static struct kunit_case stackinit_test_cases[] = {
+	/* These are explicitly initialized and should always pass. */
+	KUNIT_test_scalars(zero),
+	KUNIT_test_structs(zero),
+	KUNIT_test_structs(old_zero),
+	KUNIT_test_unions(zero),
+	KUNIT_test_unions(old_zero),
+	/* Padding here appears to be accidentally always initialized? */
+	KUNIT_test_structs(dynamic_partial),
+	KUNIT_test_structs(assigned_dynamic_partial),
+	KUNIT_test_unions(dynamic_partial),
+	KUNIT_test_unions(assigned_dynamic_partial),
+	/* Padding initialization depends on compiler behaviors. */
+	KUNIT_test_structs(static_partial),
+	KUNIT_test_structs(static_all),
+	KUNIT_test_structs(dynamic_all),
+	KUNIT_test_structs(runtime_partial),
+	KUNIT_test_structs(runtime_all),
+	KUNIT_test_structs(assigned_static_partial),
+	KUNIT_test_structs(assigned_static_all),
+	KUNIT_test_structs(assigned_dynamic_all),
+	KUNIT_test_unions(static_partial),
+	KUNIT_test_unions(static_all),
+	KUNIT_test_unions(dynamic_all),
+	KUNIT_test_unions(runtime_partial),
+	KUNIT_test_unions(runtime_all),
+	KUNIT_test_unions(assigned_static_partial),
+	KUNIT_test_unions(assigned_static_all),
+	KUNIT_test_unions(assigned_dynamic_all),
+	/* Everything fails this since it effectively performs a memcpy(). */
+	KUNIT_test_structs(assigned_copy),
+	KUNIT_test_unions(assigned_copy),
+	/* STRUCTLEAK_BYREF_ALL should cover everything from here down. */
+	KUNIT_test_scalars(none),
+	KUNIT_CASE(test_switch_1_none),
+	KUNIT_CASE(test_switch_2_none),
+	/* STRUCTLEAK_BYREF should cover from here down. */
+	KUNIT_test_structs(none),
+	/* STRUCTLEAK will only cover this. */
+	KUNIT_CASE(test_user),
+	{}
+};
+
+static struct kunit_suite stackinit_test_suite = {
+	.name = "stackinit",
+	.test_cases = stackinit_test_cases,
+};
+
+kunit_test_suites(&stackinit_test_suite);
+
+MODULE_DESCRIPTION("Test cases for compiler-based stack variable zeroing");
+MODULE_LICENSE("GPL");