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, 285 insertions, 0 deletions

diff --git a/lib/cmdline.c b/lib/cmdline.c
new file mode 100644
index 000000000..16cce6621
--- /dev/null
+++ b/lib/cmdline.c
@@ -0,0 +1,285 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/lib/cmdline.c
+ * Helper functions generally used for parsing kernel command line
+ * and module options.
+ *
+ * Code and copyrights come from init/main.c and arch/i386/kernel/setup.c.
+ *
+ * GNU Indent formatting options for this file: -kr -i8 -npsl -pcs
+ */
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+
+/*
+ *	If a hyphen was found in get_option, this will handle the
+ *	range of numbers, M-N.  This will expand the range and insert
+ *	the values[M, M+1, ..., N] into the ints array in get_options.
+ */
+
+static int get_range(char **str, int *pint, int n)
+{
+	int x, inc_counter, upper_range;
+
+	(*str)++;
+	upper_range = simple_strtol((*str), NULL, 0);
+	inc_counter = upper_range - *pint;
+	for (x = *pint; n && x < upper_range; x++, n--)
+		*pint++ = x;
+	return inc_counter;
+}
+
+/**
+ *	get_option - Parse integer from an option string
+ *	@str: option string
+ *	@pint: (optional output) integer value parsed from @str
+ *
+ *	Read an int from an option string; if available accept a subsequent
+ *	comma as well.
+ *
+ *	When @pint is NULL the function can be used as a validator of
+ *	the current option in the string.
+ *
+ *	Return:
+ *	0 - no int in string
+ *	1 - int found, no subsequent comma
+ *	2 - int found including a subsequent comma
+ *	3 - hyphen found to denote a range
+ *
+ *	Leading hyphen without integer is no integer case, but we consume it
+ *	for the sake of simplification.
+ */
+
+int get_option(char **str, int *pint)
+{
+	char *cur = *str;
+	int value;
+
+	if (!cur || !(*cur))
+		return 0;
+	if (*cur == '-')
+		value = -simple_strtoull(++cur, str, 0);
+	else
+		value = simple_strtoull(cur, str, 0);
+	if (pint)
+		*pint = value;
+	if (cur == *str)
+		return 0;
+	if (**str == ',') {
+		(*str)++;
+		return 2;
+	}
+	if (**str == '-')
+		return 3;
+
+	return 1;
+}
+EXPORT_SYMBOL(get_option);
+
+/**
+ *	get_options - Parse a string into a list of integers
+ *	@str: String to be parsed
+ *	@nints: size of integer array
+ *	@ints: integer array (must have room for at least one element)
+ *
+ *	This function parses a string containing a comma-separated
+ *	list of integers, a hyphen-separated range of _positive_ integers,
+ *	or a combination of both.  The parse halts when the array is
+ *	full, or when no more numbers can be retrieved from the
+ *	string.
+ *
+ *	When @nints is 0, the function just validates the given @str and
+ *	returns the amount of parseable integers as described below.
+ *
+ *	Returns:
+ *
+ *	The first element is filled by the number of collected integers
+ *	in the range. The rest is what was parsed from the @str.
+ *
+ *	Return value is the character in the string which caused
+ *	the parse to end (typically a null terminator, if @str is
+ *	completely parseable).
+ */
+
+char *get_options(const char *str, int nints, int *ints)
+{
+	bool validate = (nints == 0);
+	int res, i = 1;
+
+	while (i < nints || validate) {
+		int *pint = validate ? ints : ints + i;
+
+		res = get_option((char **)&str, pint);
+		if (res == 0)
+			break;
+		if (res == 3) {
+			int n = validate ? 0 : nints - i;
+			int range_nums;
+
+			range_nums = get_range((char **)&str, pint, n);
+			if (range_nums < 0)
+				break;
+			/*
+			 * Decrement the result by one to leave out the
+			 * last number in the range.  The next iteration
+			 * will handle the upper number in the range
+			 */
+			i += (range_nums - 1);
+		}
+		i++;
+		if (res == 1)
+			break;
+	}
+	ints[0] = i - 1;
+	return (char *)str;
+}
+EXPORT_SYMBOL(get_options);
+
+/**
+ *	memparse - parse a string with mem suffixes into a number
+ *	@ptr: Where parse begins
+ *	@retptr: (output) Optional pointer to next char after parse completes
+ *
+ *	Parses a string into a number.  The number stored at @ptr is
+ *	potentially suffixed with K, M, G, T, P, E.
+ *
+ *	Return: The value as recognized by simple_strtoull() multiplied
+ *	by the value as specified by suffix, if any.
+ */
+
+unsigned long long memparse(const char *ptr, char **retptr)
+{
+	char *endptr;	/* local pointer to end of parsed string */
+	unsigned long long ret = simple_strtoull(ptr, &endptr, 0);
+	unsigned int shl = 0;
+
+	/* Consume valid suffix even in case of overflow. */
+	switch (*endptr) {
+	case 'E':
+	case 'e':
+		shl += 10;
+		fallthrough;
+	case 'P':
+	case 'p':
+		shl += 10;
+		fallthrough;
+	case 'T':
+	case 't':
+		shl += 10;
+		fallthrough;
+	case 'G':
+	case 'g':
+		shl += 10;
+		fallthrough;
+	case 'M':
+	case 'm':
+		shl += 10;
+		fallthrough;
+	case 'K':
+	case 'k':
+		shl += 10;
+		fallthrough;
+	default:
+		break;
+	}
+
+	if (shl && likely(ptr != endptr)) {
+		/* Have valid suffix with preceding number. */
+		if (unlikely(check_shl_overflow(ret, shl, &ret)))
+			ret = ULLONG_MAX;
+		endptr++;
+	}
+
+	if (retptr)
+		*retptr = endptr;
+
+	return ret;
+}
+EXPORT_SYMBOL(memparse);
+
+/**
+ *	parse_option_str - Parse a string and check an option is set or not
+ *	@str: String to be parsed
+ *	@option: option name
+ *
+ *	This function parses a string containing a comma-separated list of
+ *	strings like a=b,c.
+ *
+ *	Return: True if there's such option in the string or false otherwise.
+ */
+bool parse_option_str(const char *str, const char *option)
+{
+	while (*str) {
+		if (!strncmp(str, option, strlen(option))) {
+			str += strlen(option);
+			if (!*str || *str == ',')
+				return true;
+		}
+
+		while (*str && *str != ',')
+			str++;
+
+		if (*str == ',')
+			str++;
+	}
+
+	return false;
+}
+
+/*
+ * Parse a string to get a param value pair.
+ * You can use " around spaces, but can't escape ".
+ * Hyphens and underscores equivalent in parameter names.
+ */
+char *next_arg(char *args, char **param, char **val)
+{
+	unsigned int i, equals = 0;
+	int in_quote = 0, quoted = 0;
+
+	if (*args == '"') {
+		args++;
+		in_quote = 1;
+		quoted = 1;
+	}
+
+	for (i = 0; args[i]; i++) {
+		if (isspace(args[i]) && !in_quote)
+			break;
+		if (equals == 0) {
+			if (args[i] == '=')
+				equals = i;
+		}
+		if (args[i] == '"')
+			in_quote = !in_quote;
+	}
+
+	*param = args;
+	if (!equals)
+		*val = NULL;
+	else {
+		args[equals] = '\0';
+		*val = args + equals + 1;
+
+		/* Don't include quotes in value. */
+		if (**val == '"') {
+			(*val)++;
+			if (args[i-1] == '"')
+				args[i-1] = '\0';
+		}
+	}
+	if (quoted && i > 0 && args[i-1] == '"')
+		args[i-1] = '\0';
+
+	if (args[i]) {
+		args[i] = '\0';
+		args += i + 1;
+	} else
+		args += i;
+
+	/* Chew up trailing spaces. */
+	return skip_spaces(args);
+}
+EXPORT_SYMBOL(next_arg);