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, 815 insertions, 0 deletions

diff --git a/lib/tests/scanf_kunit.c b/lib/tests/scanf_kunit.c
new file mode 100644
index 000000000..e9a36ed80
--- /dev/null
+++ b/lib/tests/scanf_kunit.c
@@ -0,0 +1,815 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Test cases for sscanf facility.
+ */
+
+#include <kunit/test.h>
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/overflow.h>
+#include <linux/prandom.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+#define BUF_SIZE 1024
+
+static char *test_buffer;
+static char *fmt_buffer;
+static struct rnd_state rnd_state;
+
+typedef void (*check_fn)(struct kunit *test, const char *file, const int line,
+			 const void *check_data, const char *string, const char *fmt, int n_args,
+			 va_list ap);
+
+static void __scanf(7, 9)
+_test(struct kunit *test, const char *file, const int line, check_fn fn, const void *check_data,
+	const char *string, const char *fmt, int n_args, ...)
+{
+	va_list ap, ap_copy;
+	int ret;
+
+	va_start(ap, n_args);
+	va_copy(ap_copy, ap);
+	ret = vsscanf(string, fmt, ap_copy);
+	va_end(ap_copy);
+
+	if (ret != n_args) {
+		KUNIT_FAIL(test, "%s:%d: vsscanf(\"%s\", \"%s\", ...) returned %d expected %d",
+			   file, line, string, fmt, ret, n_args);
+	} else {
+		(*fn)(test, file, line, check_data, string, fmt, n_args, ap);
+	}
+
+	va_end(ap);
+}
+
+#define _check_numbers_template(arg_fmt, expect, str, fmt, n_args, ap)		\
+do {										\
+	for (; n_args > 0; n_args--, expect++) {				\
+		typeof(*expect) got = *va_arg(ap, typeof(expect));		\
+		if (got != *expect) {						\
+			KUNIT_FAIL(test,					\
+				   "%s:%d: vsscanf(\"%s\", \"%s\", ...) expected " arg_fmt " got " arg_fmt, \
+				   file, line, str, fmt, *expect, got);		\
+			return;							\
+		}								\
+	}									\
+} while (0)
+
+static void check_ull(struct kunit *test, const char *file, const int line, const void *check_data,
+		      const char *string, const char *fmt, int n_args, va_list ap)
+{
+	const unsigned long long *pval = check_data;
+
+	_check_numbers_template("%llu", pval, string, fmt, n_args, ap);
+}
+
+static void check_ll(struct kunit *test, const char *file, const int line, const void *check_data,
+		     const char *string, const char *fmt, int n_args, va_list ap)
+{
+	const long long *pval = check_data;
+
+	_check_numbers_template("%lld", pval, string, fmt, n_args, ap);
+}
+
+static void check_ulong(struct kunit *test, const char *file, const int line,
+			const void *check_data, const char *string, const char *fmt, int n_args,
+			va_list ap)
+{
+	const unsigned long *pval = check_data;
+
+	_check_numbers_template("%lu", pval, string, fmt, n_args, ap);
+}
+
+static void check_long(struct kunit *test, const char *file, const int line, const void *check_data,
+		       const char *string, const char *fmt, int n_args, va_list ap)
+{
+	const long *pval = check_data;
+
+	_check_numbers_template("%ld", pval, string, fmt, n_args, ap);
+}
+
+static void check_uint(struct kunit *test, const char *file, const int line, const void *check_data,
+		       const char *string, const char *fmt, int n_args, va_list ap)
+{
+	const unsigned int *pval = check_data;
+
+	_check_numbers_template("%u", pval, string, fmt, n_args, ap);
+}
+
+static void check_int(struct kunit *test, const char *file, const int line, const void *check_data,
+		      const char *string, const char *fmt, int n_args, va_list ap)
+{
+	const int *pval = check_data;
+
+	_check_numbers_template("%d", pval, string, fmt, n_args, ap);
+}
+
+static void check_ushort(struct kunit *test, const char *file, const int line,
+			 const void *check_data, const char *string, const char *fmt, int n_args,
+			 va_list ap)
+{
+	const unsigned short *pval = check_data;
+
+	_check_numbers_template("%hu", pval, string, fmt, n_args, ap);
+}
+
+static void check_short(struct kunit *test, const char *file, const int line,
+			const void *check_data, const char *string, const char *fmt, int n_args,
+			va_list ap)
+{
+	const short *pval = check_data;
+
+	_check_numbers_template("%hd", pval, string, fmt, n_args, ap);
+}
+
+static void check_uchar(struct kunit *test, const char *file, const int line,
+			const void *check_data, const char *string, const char *fmt, int n_args,
+			va_list ap)
+{
+	const unsigned char *pval = check_data;
+
+	_check_numbers_template("%hhu", pval, string, fmt, n_args, ap);
+}
+
+static void check_char(struct kunit *test, const char *file, const int line, const void *check_data,
+		       const char *string, const char *fmt, int n_args, va_list ap)
+{
+	const signed char *pval = check_data;
+
+	_check_numbers_template("%hhd", pval, string, fmt, n_args, ap);
+}
+
+/* Selection of interesting numbers to test, copied from test-kstrtox.c */
+static const unsigned long long numbers[] = {
+	0x0ULL,
+	0x1ULL,
+	0x7fULL,
+	0x80ULL,
+	0x81ULL,
+	0xffULL,
+	0x100ULL,
+	0x101ULL,
+	0x7fffULL,
+	0x8000ULL,
+	0x8001ULL,
+	0xffffULL,
+	0x10000ULL,
+	0x10001ULL,
+	0x7fffffffULL,
+	0x80000000ULL,
+	0x80000001ULL,
+	0xffffffffULL,
+	0x100000000ULL,
+	0x100000001ULL,
+	0x7fffffffffffffffULL,
+	0x8000000000000000ULL,
+	0x8000000000000001ULL,
+	0xfffffffffffffffeULL,
+	0xffffffffffffffffULL,
+};
+
+#define value_representable_in_type(T, val)					 \
+(is_signed_type(T)								 \
+	? ((long long)(val) >= type_min(T)) && ((long long)(val) <= type_max(T)) \
+	: ((unsigned long long)(val) <= type_max(T)))
+
+
+#define test_one_number(T, gen_fmt, scan_fmt, val, fn)			\
+do {									\
+	const T expect_val = (T)(val);					\
+	T result = ~expect_val; /* should be overwritten */		\
+									\
+	snprintf(test_buffer, BUF_SIZE, gen_fmt, expect_val);		\
+	_test(test, __FILE__, __LINE__, fn, &expect_val, test_buffer, "%" scan_fmt, 1, &result);\
+} while (0)
+
+#define simple_numbers_loop(T, gen_fmt, scan_fmt, fn)			\
+do {									\
+	int i;								\
+									\
+	for (i = 0; i < ARRAY_SIZE(numbers); i++) {			\
+		if (value_representable_in_type(T, numbers[i]))		\
+			test_one_number(T, gen_fmt, scan_fmt,		\
+					numbers[i], fn);		\
+									\
+		if (value_representable_in_type(T, -numbers[i]))	\
+			test_one_number(T, gen_fmt, scan_fmt,		\
+					-numbers[i], fn);		\
+	}								\
+} while (0)
+
+static void numbers_simple(struct kunit *test)
+{
+	simple_numbers_loop(unsigned long long,	"%llu",	  "llu", check_ull);
+	simple_numbers_loop(long long,		"%lld",	  "lld", check_ll);
+	simple_numbers_loop(long long,		"%lld",	  "lli", check_ll);
+	simple_numbers_loop(unsigned long long,	"%llx",	  "llx", check_ull);
+	simple_numbers_loop(long long,		"%llx",	  "llx", check_ll);
+	simple_numbers_loop(long long,		"0x%llx", "lli", check_ll);
+	simple_numbers_loop(unsigned long long, "0x%llx", "llx", check_ull);
+	simple_numbers_loop(long long,		"0x%llx", "llx", check_ll);
+
+	simple_numbers_loop(unsigned long,	"%lu",	  "lu", check_ulong);
+	simple_numbers_loop(long,		"%ld",	  "ld", check_long);
+	simple_numbers_loop(long,		"%ld",	  "li", check_long);
+	simple_numbers_loop(unsigned long,	"%lx",	  "lx", check_ulong);
+	simple_numbers_loop(long,		"%lx",	  "lx", check_long);
+	simple_numbers_loop(long,		"0x%lx",  "li", check_long);
+	simple_numbers_loop(unsigned long,	"0x%lx",  "lx", check_ulong);
+	simple_numbers_loop(long,		"0x%lx",  "lx", check_long);
+
+	simple_numbers_loop(unsigned int,	"%u",	  "u", check_uint);
+	simple_numbers_loop(int,		"%d",	  "d", check_int);
+	simple_numbers_loop(int,		"%d",	  "i", check_int);
+	simple_numbers_loop(unsigned int,	"%x",	  "x", check_uint);
+	simple_numbers_loop(int,		"%x",	  "x", check_int);
+	simple_numbers_loop(int,		"0x%x",   "i", check_int);
+	simple_numbers_loop(unsigned int,	"0x%x",   "x", check_uint);
+	simple_numbers_loop(int,		"0x%x",   "x", check_int);
+
+	simple_numbers_loop(unsigned short,	"%hu",	  "hu", check_ushort);
+	simple_numbers_loop(short,		"%hd",	  "hd", check_short);
+	simple_numbers_loop(short,		"%hd",	  "hi", check_short);
+	simple_numbers_loop(unsigned short,	"%hx",	  "hx", check_ushort);
+	simple_numbers_loop(short,		"%hx",	  "hx", check_short);
+	simple_numbers_loop(short,		"0x%hx",  "hi", check_short);
+	simple_numbers_loop(unsigned short,	"0x%hx",  "hx", check_ushort);
+	simple_numbers_loop(short,		"0x%hx",  "hx", check_short);
+
+	simple_numbers_loop(unsigned char,	"%hhu",	  "hhu", check_uchar);
+	simple_numbers_loop(signed char,	"%hhd",	  "hhd", check_char);
+	simple_numbers_loop(signed char,	"%hhd",	  "hhi", check_char);
+	simple_numbers_loop(unsigned char,	"%hhx",	  "hhx", check_uchar);
+	simple_numbers_loop(signed char,	"%hhx",	  "hhx", check_char);
+	simple_numbers_loop(signed char,	"0x%hhx", "hhi", check_char);
+	simple_numbers_loop(unsigned char,	"0x%hhx", "hhx", check_uchar);
+	simple_numbers_loop(signed char,	"0x%hhx", "hhx", check_char);
+}
+
+/*
+ * This gives a better variety of number "lengths" in a small sample than
+ * the raw prandom*() functions (Not mathematically rigorous!!).
+ * Variabilty of length and value is more important than perfect randomness.
+ */
+static u32 next_test_random(u32 max_bits)
+{
+	u32 n_bits = hweight32(prandom_u32_state(&rnd_state)) % (max_bits + 1);
+
+	return prandom_u32_state(&rnd_state) & GENMASK(n_bits, 0);
+}
+
+static unsigned long long next_test_random_ull(void)
+{
+	u32 rand1 = prandom_u32_state(&rnd_state);
+	u32 n_bits = (hweight32(rand1) * 3) % 64;
+	u64 val = (u64)prandom_u32_state(&rnd_state) * rand1;
+
+	return val & GENMASK_ULL(n_bits, 0);
+}
+
+#define random_for_type(T)				\
+	((T)(sizeof(T) <= sizeof(u32)			\
+		? next_test_random(BITS_PER_TYPE(T))	\
+		: next_test_random_ull()))
+
+/*
+ * Define a pattern of negative and positive numbers to ensure we get
+ * some of both within the small number of samples in a test string.
+ */
+#define NEGATIVES_PATTERN 0x3246	/* 00110010 01000110 */
+
+#define fill_random_array(arr)							\
+do {										\
+	unsigned int neg_pattern = NEGATIVES_PATTERN;				\
+	int i;									\
+										\
+	for (i = 0; i < ARRAY_SIZE(arr); i++, neg_pattern >>= 1) {		\
+		(arr)[i] = random_for_type(typeof((arr)[0]));			\
+		if (is_signed_type(typeof((arr)[0])) && (neg_pattern & 1))	\
+			(arr)[i] = -(arr)[i];					\
+	}									\
+} while (0)
+
+/*
+ * Convenience wrapper around snprintf() to append at buf_pos in buf,
+ * updating buf_pos and returning the number of characters appended.
+ * On error buf_pos is not changed and return value is 0.
+ */
+static int __printf(4, 5)
+append_fmt(char *buf, int *buf_pos, int buf_len, const char *val_fmt, ...)
+{
+	va_list ap;
+	int field_len;
+
+	va_start(ap, val_fmt);
+	field_len = vsnprintf(buf + *buf_pos, buf_len - *buf_pos, val_fmt, ap);
+	va_end(ap);
+
+	if (field_len < 0)
+		field_len = 0;
+
+	*buf_pos += field_len;
+
+	return field_len;
+}
+
+/*
+ * Convenience function to append the field delimiter string
+ * to both the value string and format string buffers.
+ */
+static void append_delim(char *str_buf, int *str_buf_pos, int str_buf_len,
+				char *fmt_buf, int *fmt_buf_pos, int fmt_buf_len,
+				const char *delim_str)
+{
+	append_fmt(str_buf, str_buf_pos, str_buf_len, delim_str);
+	append_fmt(fmt_buf, fmt_buf_pos, fmt_buf_len, delim_str);
+}
+
+#define test_array_8(fn, check_data, string, fmt, arr)				\
+do {										\
+	BUILD_BUG_ON(ARRAY_SIZE(arr) != 8);					\
+	_test(test, __FILE__, __LINE__, fn, check_data, string, fmt, 8,		\
+		&(arr)[0], &(arr)[1], &(arr)[2], &(arr)[3],			\
+		&(arr)[4], &(arr)[5], &(arr)[6], &(arr)[7]);			\
+} while (0)
+
+#define numbers_list_8(T, gen_fmt, field_sep, scan_fmt, fn)			\
+do {										\
+	int i, pos = 0, fmt_pos = 0;						\
+	T expect[8], result[8];							\
+										\
+	fill_random_array(expect);						\
+										\
+	for (i = 0; i < ARRAY_SIZE(expect); i++) {				\
+		if (i != 0)							\
+			append_delim(test_buffer, &pos, BUF_SIZE,		\
+				     fmt_buffer, &fmt_pos, BUF_SIZE,		\
+				     field_sep);				\
+										\
+		append_fmt(test_buffer, &pos, BUF_SIZE, gen_fmt, expect[i]);	\
+		append_fmt(fmt_buffer, &fmt_pos, BUF_SIZE, "%%%s", scan_fmt);	\
+	}									\
+										\
+	test_array_8(fn, expect, test_buffer, fmt_buffer, result);		\
+} while (0)
+
+#define numbers_list_fix_width(T, gen_fmt, field_sep, width, scan_fmt, fn)	\
+do {										\
+	char full_fmt[16];							\
+										\
+	snprintf(full_fmt, sizeof(full_fmt), "%u%s", width, scan_fmt);		\
+	numbers_list_8(T, gen_fmt, field_sep, full_fmt, fn);			\
+} while (0)
+
+#define numbers_list_val_width(T, gen_fmt, field_sep, scan_fmt, fn)		\
+do {										\
+	int i, val_len, pos = 0, fmt_pos = 0;					\
+	T expect[8], result[8];							\
+										\
+	fill_random_array(expect);						\
+										\
+	for (i = 0; i < ARRAY_SIZE(expect); i++) {				\
+		if (i != 0)							\
+			append_delim(test_buffer, &pos, BUF_SIZE,		\
+				     fmt_buffer, &fmt_pos, BUF_SIZE, field_sep);\
+										\
+		val_len = append_fmt(test_buffer, &pos, BUF_SIZE, gen_fmt,	\
+				     expect[i]);				\
+		append_fmt(fmt_buffer, &fmt_pos, BUF_SIZE,			\
+			   "%%%u%s", val_len, scan_fmt);			\
+	}									\
+										\
+	test_array_8(fn, expect, test_buffer, fmt_buffer, result);		\
+} while (0)
+
+static void numbers_list_ll(struct kunit *test, const char *delim)
+{
+	numbers_list_8(unsigned long long, "%llu",   delim, "llu", check_ull);
+	numbers_list_8(long long,	   "%lld",   delim, "lld", check_ll);
+	numbers_list_8(long long,	   "%lld",   delim, "lli", check_ll);
+	numbers_list_8(unsigned long long, "%llx",   delim, "llx", check_ull);
+	numbers_list_8(unsigned long long, "0x%llx", delim, "llx", check_ull);
+	numbers_list_8(long long,	   "0x%llx", delim, "lli", check_ll);
+}
+
+static void numbers_list_l(struct kunit *test, const char *delim)
+{
+	numbers_list_8(unsigned long,	   "%lu",    delim, "lu", check_ulong);
+	numbers_list_8(long,		   "%ld",    delim, "ld", check_long);
+	numbers_list_8(long,		   "%ld",    delim, "li", check_long);
+	numbers_list_8(unsigned long,	   "%lx",    delim, "lx", check_ulong);
+	numbers_list_8(unsigned long,	   "0x%lx",  delim, "lx", check_ulong);
+	numbers_list_8(long,		   "0x%lx",  delim, "li", check_long);
+}
+
+static void numbers_list_d(struct kunit *test, const char *delim)
+{
+	numbers_list_8(unsigned int,	   "%u",     delim, "u", check_uint);
+	numbers_list_8(int,		   "%d",     delim, "d", check_int);
+	numbers_list_8(int,		   "%d",     delim, "i", check_int);
+	numbers_list_8(unsigned int,	   "%x",     delim, "x", check_uint);
+	numbers_list_8(unsigned int,	   "0x%x",   delim, "x", check_uint);
+	numbers_list_8(int,		   "0x%x",   delim, "i", check_int);
+}
+
+static void numbers_list_h(struct kunit *test, const char *delim)
+{
+	numbers_list_8(unsigned short,	   "%hu",    delim, "hu", check_ushort);
+	numbers_list_8(short,		   "%hd",    delim, "hd", check_short);
+	numbers_list_8(short,		   "%hd",    delim, "hi", check_short);
+	numbers_list_8(unsigned short,	   "%hx",    delim, "hx", check_ushort);
+	numbers_list_8(unsigned short,	   "0x%hx",  delim, "hx", check_ushort);
+	numbers_list_8(short,		   "0x%hx",  delim, "hi", check_short);
+}
+
+static void numbers_list_hh(struct kunit *test, const char *delim)
+{
+	numbers_list_8(unsigned char,	   "%hhu",   delim, "hhu", check_uchar);
+	numbers_list_8(signed char,	   "%hhd",   delim, "hhd", check_char);
+	numbers_list_8(signed char,	   "%hhd",   delim, "hhi", check_char);
+	numbers_list_8(unsigned char,	   "%hhx",   delim, "hhx", check_uchar);
+	numbers_list_8(unsigned char,	   "0x%hhx", delim, "hhx", check_uchar);
+	numbers_list_8(signed char,	   "0x%hhx", delim, "hhi", check_char);
+}
+
+static void numbers_list(struct kunit *test)
+{
+	const char * const *param = test->param_value;
+	const char *delim = *param;
+
+	numbers_list_ll(test, delim);
+	numbers_list_l(test, delim);
+	numbers_list_d(test, delim);
+	numbers_list_h(test, delim);
+	numbers_list_hh(test, delim);
+}
+
+static void numbers_list_field_width_ll(struct kunit *test, const char *delim)
+{
+	numbers_list_fix_width(unsigned long long, "%llu",   delim, 20, "llu", check_ull);
+	numbers_list_fix_width(long long,	   "%lld",   delim, 20, "lld", check_ll);
+	numbers_list_fix_width(long long,	   "%lld",   delim, 20, "lli", check_ll);
+	numbers_list_fix_width(unsigned long long, "%llx",   delim, 16, "llx", check_ull);
+	numbers_list_fix_width(unsigned long long, "0x%llx", delim, 18, "llx", check_ull);
+	numbers_list_fix_width(long long,	   "0x%llx", delim, 18, "lli", check_ll);
+}
+
+static void numbers_list_field_width_l(struct kunit *test, const char *delim)
+{
+#if BITS_PER_LONG == 64
+	numbers_list_fix_width(unsigned long,	"%lu",	     delim, 20, "lu", check_ulong);
+	numbers_list_fix_width(long,		"%ld",	     delim, 20, "ld", check_long);
+	numbers_list_fix_width(long,		"%ld",	     delim, 20, "li", check_long);
+	numbers_list_fix_width(unsigned long,	"%lx",	     delim, 16, "lx", check_ulong);
+	numbers_list_fix_width(unsigned long,	"0x%lx",     delim, 18, "lx", check_ulong);
+	numbers_list_fix_width(long,		"0x%lx",     delim, 18, "li", check_long);
+#else
+	numbers_list_fix_width(unsigned long,	"%lu",	     delim, 10, "lu", check_ulong);
+	numbers_list_fix_width(long,		"%ld",	     delim, 11, "ld", check_long);
+	numbers_list_fix_width(long,		"%ld",	     delim, 11, "li", check_long);
+	numbers_list_fix_width(unsigned long,	"%lx",	     delim, 8,  "lx", check_ulong);
+	numbers_list_fix_width(unsigned long,	"0x%lx",     delim, 10, "lx", check_ulong);
+	numbers_list_fix_width(long,		"0x%lx",     delim, 10, "li", check_long);
+#endif
+}
+
+static void numbers_list_field_width_d(struct kunit *test, const char *delim)
+{
+	numbers_list_fix_width(unsigned int,	"%u",	     delim, 10, "u", check_uint);
+	numbers_list_fix_width(int,		"%d",	     delim, 11, "d", check_int);
+	numbers_list_fix_width(int,		"%d",	     delim, 11, "i", check_int);
+	numbers_list_fix_width(unsigned int,	"%x",	     delim, 8,  "x", check_uint);
+	numbers_list_fix_width(unsigned int,	"0x%x",	     delim, 10, "x", check_uint);
+	numbers_list_fix_width(int,		"0x%x",	     delim, 10, "i", check_int);
+}
+
+static void numbers_list_field_width_h(struct kunit *test, const char *delim)
+{
+	numbers_list_fix_width(unsigned short,	"%hu",	     delim, 5, "hu", check_ushort);
+	numbers_list_fix_width(short,		"%hd",	     delim, 6, "hd", check_short);
+	numbers_list_fix_width(short,		"%hd",	     delim, 6, "hi", check_short);
+	numbers_list_fix_width(unsigned short,	"%hx",	     delim, 4, "hx", check_ushort);
+	numbers_list_fix_width(unsigned short,	"0x%hx",     delim, 6, "hx", check_ushort);
+	numbers_list_fix_width(short,		"0x%hx",     delim, 6, "hi", check_short);
+}
+
+static void numbers_list_field_width_hh(struct kunit *test, const char *delim)
+{
+	numbers_list_fix_width(unsigned char,	"%hhu",	     delim, 3, "hhu", check_uchar);
+	numbers_list_fix_width(signed char,	"%hhd",	     delim, 4, "hhd", check_char);
+	numbers_list_fix_width(signed char,	"%hhd",	     delim, 4, "hhi", check_char);
+	numbers_list_fix_width(unsigned char,	"%hhx",	     delim, 2, "hhx", check_uchar);
+	numbers_list_fix_width(unsigned char,	"0x%hhx",    delim, 4, "hhx", check_uchar);
+	numbers_list_fix_width(signed char,	"0x%hhx",    delim, 4, "hhi", check_char);
+}
+
+/*
+ * List of numbers separated by delim. Each field width specifier is the
+ * maximum possible digits for the given type and base.
+ */
+static void numbers_list_field_width_typemax(struct kunit *test)
+{
+	const char * const *param = test->param_value;
+	const char *delim = *param;
+
+	numbers_list_field_width_ll(test, delim);
+	numbers_list_field_width_l(test, delim);
+	numbers_list_field_width_d(test, delim);
+	numbers_list_field_width_h(test, delim);
+	numbers_list_field_width_hh(test, delim);
+}
+
+static void numbers_list_field_width_val_ll(struct kunit *test, const char *delim)
+{
+	numbers_list_val_width(unsigned long long, "%llu",   delim, "llu", check_ull);
+	numbers_list_val_width(long long,	   "%lld",   delim, "lld", check_ll);
+	numbers_list_val_width(long long,	   "%lld",   delim, "lli", check_ll);
+	numbers_list_val_width(unsigned long long, "%llx",   delim, "llx", check_ull);
+	numbers_list_val_width(unsigned long long, "0x%llx", delim, "llx", check_ull);
+	numbers_list_val_width(long long,	   "0x%llx", delim, "lli", check_ll);
+}
+
+static void numbers_list_field_width_val_l(struct kunit *test, const char *delim)
+{
+	numbers_list_val_width(unsigned long,	"%lu",	     delim, "lu", check_ulong);
+	numbers_list_val_width(long,		"%ld",	     delim, "ld", check_long);
+	numbers_list_val_width(long,		"%ld",	     delim, "li", check_long);
+	numbers_list_val_width(unsigned long,	"%lx",	     delim, "lx", check_ulong);
+	numbers_list_val_width(unsigned long,	"0x%lx",     delim, "lx", check_ulong);
+	numbers_list_val_width(long,		"0x%lx",     delim, "li", check_long);
+}
+
+static void numbers_list_field_width_val_d(struct kunit *test, const char *delim)
+{
+	numbers_list_val_width(unsigned int,	"%u",	     delim, "u", check_uint);
+	numbers_list_val_width(int,		"%d",	     delim, "d", check_int);
+	numbers_list_val_width(int,		"%d",	     delim, "i", check_int);
+	numbers_list_val_width(unsigned int,	"%x",	     delim, "x", check_uint);
+	numbers_list_val_width(unsigned int,	"0x%x",	     delim, "x", check_uint);
+	numbers_list_val_width(int,		"0x%x",	     delim, "i", check_int);
+}
+
+static void numbers_list_field_width_val_h(struct kunit *test, const char *delim)
+{
+	numbers_list_val_width(unsigned short,	"%hu",	     delim, "hu", check_ushort);
+	numbers_list_val_width(short,		"%hd",	     delim, "hd", check_short);
+	numbers_list_val_width(short,		"%hd",	     delim, "hi", check_short);
+	numbers_list_val_width(unsigned short,	"%hx",	     delim, "hx", check_ushort);
+	numbers_list_val_width(unsigned short,	"0x%hx",     delim, "hx", check_ushort);
+	numbers_list_val_width(short,		"0x%hx",     delim, "hi", check_short);
+}
+
+static void numbers_list_field_width_val_hh(struct kunit *test, const char *delim)
+{
+	numbers_list_val_width(unsigned char,	"%hhu",	     delim, "hhu", check_uchar);
+	numbers_list_val_width(signed char,	"%hhd",	     delim, "hhd", check_char);
+	numbers_list_val_width(signed char,	"%hhd",	     delim, "hhi", check_char);
+	numbers_list_val_width(unsigned char,	"%hhx",	     delim, "hhx", check_uchar);
+	numbers_list_val_width(unsigned char,	"0x%hhx",    delim, "hhx", check_uchar);
+	numbers_list_val_width(signed char,	"0x%hhx",    delim, "hhi", check_char);
+}
+
+/*
+ * List of numbers separated by delim. Each field width specifier is the
+ * exact length of the corresponding value digits in the string being scanned.
+ */
+static void numbers_list_field_width_val_width(struct kunit *test)
+{
+	const char * const *param = test->param_value;
+	const char *delim = *param;
+
+	numbers_list_field_width_val_ll(test, delim);
+	numbers_list_field_width_val_l(test, delim);
+	numbers_list_field_width_val_d(test, delim);
+	numbers_list_field_width_val_h(test, delim);
+	numbers_list_field_width_val_hh(test, delim);
+}
+
+/*
+ * Slice a continuous string of digits without field delimiters, containing
+ * numbers of varying length, using the field width to extract each group
+ * of digits. For example the hex values c0,3,bf01,303 would have a
+ * string representation of "c03bf01303" and extracted with "%2x%1x%4x%3x".
+ */
+static void numbers_slice(struct kunit *test)
+{
+	const char *delim = "";
+
+	KUNIT_ASSERT_PTR_EQ(test, test->param_value, NULL);
+	test->param_value = &delim;
+
+	numbers_list_field_width_val_width(test);
+}
+
+#define test_number_prefix(T, str, scan_fmt, expect0, expect1, n_args, fn)	\
+do {										\
+	const T expect[2] = { expect0, expect1 };				\
+	T result[2] = { (T)~expect[0], (T)~expect[1] };				\
+										\
+	_test(test, __FILE__, __LINE__, fn, &expect, str, scan_fmt, n_args, &result[0], &result[1]);\
+} while (0)
+
+/*
+ * Number prefix is >= field width.
+ * Expected behaviour is derived from testing userland sscanf.
+ */
+static void numbers_prefix_overflow(struct kunit *test)
+{
+	/*
+	 * Negative decimal with a field of width 1, should quit scanning
+	 * and return 0.
+	 */
+	test_number_prefix(long long,	"-1 1", "%1lld %lld",	0, 0, 0, check_ll);
+	test_number_prefix(long,	"-1 1", "%1ld %ld",	0, 0, 0, check_long);
+	test_number_prefix(int,		"-1 1", "%1d %d",	0, 0, 0, check_int);
+	test_number_prefix(short,	"-1 1", "%1hd %hd",	0, 0, 0, check_short);
+	test_number_prefix(signed char,	"-1 1", "%1hhd %hhd",	0, 0, 0, check_char);
+
+	test_number_prefix(long long,	"-1 1", "%1lli %lli",	0, 0, 0, check_ll);
+	test_number_prefix(long,	"-1 1", "%1li %li",	0, 0, 0, check_long);
+	test_number_prefix(int,		"-1 1", "%1i %i",	0, 0, 0, check_int);
+	test_number_prefix(short,	"-1 1", "%1hi %hi",	0, 0, 0, check_short);
+	test_number_prefix(signed char,	"-1 1", "%1hhi %hhi",	0, 0, 0, check_char);
+
+	/*
+	 * 0x prefix in a field of width 1: 0 is a valid digit so should
+	 * convert. Next field scan starts at the 'x' which isn't a digit so
+	 * scan quits with one field converted.
+	 */
+	test_number_prefix(unsigned long long,	"0xA7", "%1llx%llx", 0, 0, 1, check_ull);
+	test_number_prefix(unsigned long,	"0xA7", "%1lx%lx",   0, 0, 1, check_ulong);
+	test_number_prefix(unsigned int,	"0xA7", "%1x%x",     0, 0, 1, check_uint);
+	test_number_prefix(unsigned short,	"0xA7", "%1hx%hx",   0, 0, 1, check_ushort);
+	test_number_prefix(unsigned char,	"0xA7", "%1hhx%hhx", 0, 0, 1, check_uchar);
+	test_number_prefix(long long,		"0xA7", "%1lli%llx", 0, 0, 1, check_ll);
+	test_number_prefix(long,		"0xA7", "%1li%lx",   0, 0, 1, check_long);
+	test_number_prefix(int,			"0xA7", "%1i%x",     0, 0, 1, check_int);
+	test_number_prefix(short,		"0xA7", "%1hi%hx",   0, 0, 1, check_short);
+	test_number_prefix(char,		"0xA7", "%1hhi%hhx", 0, 0, 1, check_char);
+
+	/*
+	 * 0x prefix in a field of width 2 using %x conversion: first field
+	 * converts to 0. Next field scan starts at the character after "0x".
+	 * Both fields will convert.
+	 */
+	test_number_prefix(unsigned long long,	"0xA7", "%2llx%llx", 0, 0xa7, 2, check_ull);
+	test_number_prefix(unsigned long,	"0xA7", "%2lx%lx",   0, 0xa7, 2, check_ulong);
+	test_number_prefix(unsigned int,	"0xA7", "%2x%x",     0, 0xa7, 2, check_uint);
+	test_number_prefix(unsigned short,	"0xA7", "%2hx%hx",   0, 0xa7, 2, check_ushort);
+	test_number_prefix(unsigned char,	"0xA7", "%2hhx%hhx", 0, 0xa7, 2, check_uchar);
+
+	/*
+	 * 0x prefix in a field of width 2 using %i conversion: first field
+	 * converts to 0. Next field scan starts at the character after "0x",
+	 * which will convert if can be interpreted as decimal but will fail
+	 * if it contains any hex digits (since no 0x prefix).
+	 */
+	test_number_prefix(long long,	"0x67", "%2lli%lli", 0, 67, 2, check_ll);
+	test_number_prefix(long,	"0x67", "%2li%li",   0, 67, 2, check_long);
+	test_number_prefix(int,		"0x67", "%2i%i",     0, 67, 2, check_int);
+	test_number_prefix(short,	"0x67", "%2hi%hi",   0, 67, 2, check_short);
+	test_number_prefix(char,	"0x67", "%2hhi%hhi", 0, 67, 2, check_char);
+
+	test_number_prefix(long long,	"0xA7", "%2lli%lli", 0, 0,  1, check_ll);
+	test_number_prefix(long,	"0xA7", "%2li%li",   0, 0,  1, check_long);
+	test_number_prefix(int,		"0xA7", "%2i%i",     0, 0,  1, check_int);
+	test_number_prefix(short,	"0xA7", "%2hi%hi",   0, 0,  1, check_short);
+	test_number_prefix(char,	"0xA7", "%2hhi%hhi", 0, 0,  1, check_char);
+}
+
+#define _test_simple_strtoxx(T, fn, gen_fmt, expect, base)			\
+do {										\
+	T got;									\
+	char *endp;								\
+	int len;								\
+										\
+	len = snprintf(test_buffer, BUF_SIZE, gen_fmt, expect);			\
+	got = (fn)(test_buffer, &endp, base);					\
+	if (got != (expect)) {							\
+		KUNIT_FAIL(test, #fn "(\"%s\", %d): got " gen_fmt " expected " gen_fmt, \
+			   test_buffer, base, got, expect);			\
+	} else if (endp != test_buffer + len) {					\
+		KUNIT_FAIL(test, #fn "(\"%s\", %d) startp=0x%px got endp=0x%px expected 0x%px", \
+			   test_buffer, base, test_buffer,			\
+			   test_buffer + len, endp);				\
+	}									\
+} while (0)
+
+#define test_simple_strtoxx(T, fn, gen_fmt, base)				\
+do {										\
+	int i;									\
+										\
+	for (i = 0; i < ARRAY_SIZE(numbers); i++) {				\
+		_test_simple_strtoxx(T, fn, gen_fmt, (T)numbers[i], base);	\
+										\
+		if (is_signed_type(T))						\
+			_test_simple_strtoxx(T, fn, gen_fmt,			\
+					      -(T)numbers[i], base);		\
+	}									\
+} while (0)
+
+static void test_simple_strtoull(struct kunit *test)
+{
+	test_simple_strtoxx(unsigned long long, simple_strtoull, "%llu",   10);
+	test_simple_strtoxx(unsigned long long, simple_strtoull, "%llu",   0);
+	test_simple_strtoxx(unsigned long long, simple_strtoull, "%llx",   16);
+	test_simple_strtoxx(unsigned long long, simple_strtoull, "0x%llx", 16);
+	test_simple_strtoxx(unsigned long long, simple_strtoull, "0x%llx", 0);
+}
+
+static void test_simple_strtoll(struct kunit *test)
+{
+	test_simple_strtoxx(long long, simple_strtoll, "%lld",	 10);
+	test_simple_strtoxx(long long, simple_strtoll, "%lld",	 0);
+	test_simple_strtoxx(long long, simple_strtoll, "%llx",	 16);
+	test_simple_strtoxx(long long, simple_strtoll, "0x%llx", 16);
+	test_simple_strtoxx(long long, simple_strtoll, "0x%llx", 0);
+}
+
+static void test_simple_strtoul(struct kunit *test)
+{
+	test_simple_strtoxx(unsigned long, simple_strtoul, "%lu",   10);
+	test_simple_strtoxx(unsigned long, simple_strtoul, "%lu",   0);
+	test_simple_strtoxx(unsigned long, simple_strtoul, "%lx",   16);
+	test_simple_strtoxx(unsigned long, simple_strtoul, "0x%lx", 16);
+	test_simple_strtoxx(unsigned long, simple_strtoul, "0x%lx", 0);
+}
+
+static void test_simple_strtol(struct kunit *test)
+{
+	test_simple_strtoxx(long, simple_strtol, "%ld",   10);
+	test_simple_strtoxx(long, simple_strtol, "%ld",   0);
+	test_simple_strtoxx(long, simple_strtol, "%lx",   16);
+	test_simple_strtoxx(long, simple_strtol, "0x%lx", 16);
+	test_simple_strtoxx(long, simple_strtol, "0x%lx", 0);
+}
+
+/* Selection of common delimiters/separators between numbers in a string. */
+static const char * const number_delimiters[] = {
+	" ", ":", ",", "-", "/",
+};
+
+static void number_delimiter_param_desc(const char * const *param,
+					   char *desc)
+{
+	snprintf(desc, KUNIT_PARAM_DESC_SIZE, "\"%s\"", *param);
+}
+
+KUNIT_ARRAY_PARAM(number_delimiters, number_delimiters, number_delimiter_param_desc);
+
+static struct kunit_case scanf_test_cases[] = {
+	KUNIT_CASE(numbers_simple),
+	/* String with multiple numbers separated by delimiter. */
+	KUNIT_CASE_PARAM(numbers_list, number_delimiters_gen_params),
+	/* Field width may be longer than actual field digits. */
+	KUNIT_CASE_PARAM(numbers_list_field_width_typemax, number_delimiters_gen_params),
+	/* Each field width exactly length of actual field digits. */
+	KUNIT_CASE_PARAM(numbers_list_field_width_val_width, number_delimiters_gen_params),
+	/* Slice continuous sequence of digits using field widths. */
+	KUNIT_CASE(numbers_slice),
+	KUNIT_CASE(numbers_prefix_overflow),
+
+	KUNIT_CASE(test_simple_strtoull),
+	KUNIT_CASE(test_simple_strtoll),
+	KUNIT_CASE(test_simple_strtoul),
+	KUNIT_CASE(test_simple_strtol),
+	{}
+};
+
+static int scanf_suite_init(struct kunit_suite *suite)
+{
+	test_buffer = kmalloc(BUF_SIZE, GFP_KERNEL);
+	if (!test_buffer)
+		return -ENOMEM;
+
+	fmt_buffer = kmalloc(BUF_SIZE, GFP_KERNEL);
+	if (!fmt_buffer) {
+		kfree(test_buffer);
+		return -ENOMEM;
+	}
+
+	prandom_seed_state(&rnd_state, 3141592653589793238ULL);
+
+	return 0;
+}
+
+static void scanf_suite_exit(struct kunit_suite *suite)
+{
+	kfree(fmt_buffer);
+	kfree(test_buffer);
+}
+
+static struct kunit_suite scanf_test_suite = {
+	.name = "scanf",
+	.suite_init = scanf_suite_init,
+	.suite_exit = scanf_suite_exit,
+	.test_cases = scanf_test_cases,
+};
+
+kunit_test_suite(scanf_test_suite);
+
+MODULE_AUTHOR("Richard Fitzgerald <rf@opensource.cirrus.com>");
+MODULE_DESCRIPTION("Test cases for sscanf facility");
+MODULE_LICENSE("GPL v2");