From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Sun, 30 Aug 2026 09:22:00 -0700
Subject: Merge tag 'trace-v7.3-2' of
 git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

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
---
 tools/perf/util/string.c | 460 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 460 insertions(+)
 create mode 100644 tools/perf/util/string.c

(limited to 'tools/perf/util/string.c')

diff --git a/tools/perf/util/string.c b/tools/perf/util/string.c
new file mode 100644
index 000000000..c0e927bba
--- /dev/null
+++ b/tools/perf/util/string.c
@@ -0,0 +1,460 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "string2.h"
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <stdlib.h>
+
+#include <linux/ctype.h>
+
+const char *graph_dotted_line =
+	"---------------------------------------------------------------------"
+	"---------------------------------------------------------------------"
+	"---------------------------------------------------------------------";
+const char *dots =
+	"....................................................................."
+	"....................................................................."
+	".....................................................................";
+
+/*
+ * perf_atoll()
+ * Parse (\d+)(b|B|kb|KB|mb|MB|gb|GB|tb|TB) (e.g. "256MB")
+ * and return its numeric value
+ */
+s64 perf_atoll(const char *str)
+{
+	s64 length;
+	char *p;
+	char c;
+
+	if (!isdigit(str[0]))
+		goto out_err;
+
+	length = strtoll(str, &p, 10);
+	switch (c = *p++) {
+		case 'b': case 'B':
+			if (*p)
+				goto out_err;
+
+			fallthrough;
+		case '\0':
+			return length;
+		default:
+			goto out_err;
+		/* two-letter suffices */
+		case 'k': case 'K':
+			length <<= 10;
+			break;
+		case 'm': case 'M':
+			length <<= 20;
+			break;
+		case 'g': case 'G':
+			length <<= 30;
+			break;
+		case 't': case 'T':
+			length <<= 40;
+			break;
+	}
+	/* we want the cases to match */
+	if (islower(c)) {
+		if (strcmp(p, "b") != 0)
+			goto out_err;
+	} else {
+		if (strcmp(p, "B") != 0)
+			goto out_err;
+	}
+	return length;
+
+out_err:
+	return -1;
+}
+
+/* Character class matching */
+static bool __match_charclass(const char *pat, char c, const char **npat)
+{
+	bool complement = false, ret = true;
+
+	if (*pat == '!') {
+		complement = true;
+		pat++;
+	}
+	if (*pat++ == c)	/* First character is special */
+		goto end;
+
+	while (*pat && *pat != ']') {	/* Matching */
+		if (*pat == '-' && *(pat + 1) != ']') {	/* Range */
+			if (*(pat - 1) <= c && c <= *(pat + 1))
+				goto end;
+			if (*(pat - 1) > *(pat + 1))
+				goto error;
+			pat += 2;
+		} else if (*pat++ == c)
+			goto end;
+	}
+	if (!*pat)
+		goto error;
+	ret = false;
+
+end:
+	while (*pat && *pat != ']')	/* Searching closing */
+		pat++;
+	if (!*pat)
+		goto error;
+	*npat = pat + 1;
+	return complement ? !ret : ret;
+
+error:
+	return false;
+}
+
+/* Glob/lazy pattern matching */
+static bool __match_glob(const char *str, const char *pat, bool ignore_space,
+			bool case_ins)
+{
+	while (*str && *pat && *pat != '*') {
+		if (ignore_space) {
+			/* Ignore spaces for lazy matching */
+			if (isspace(*str)) {
+				str++;
+				continue;
+			}
+			if (isspace(*pat)) {
+				pat++;
+				continue;
+			}
+		}
+		if (*pat == '?') {	/* Matches any single character */
+			str++;
+			pat++;
+			continue;
+		} else if (*pat == '[')	/* Character classes/Ranges */
+			if (__match_charclass(pat + 1, *str, &pat)) {
+				str++;
+				continue;
+			} else
+				return false;
+		else if (*pat == '\\') /* Escaped char match as normal char */
+			pat++;
+		if (case_ins) {
+			if (tolower(*str) != tolower(*pat))
+				return false;
+		} else if (*str != *pat)
+			return false;
+		str++;
+		pat++;
+	}
+	/* Check wild card */
+	if (*pat == '*') {
+		while (*pat == '*')
+			pat++;
+		if (!*pat)	/* Tail wild card matches all */
+			return true;
+		while (*str)
+			if (__match_glob(str++, pat, ignore_space, case_ins))
+				return true;
+	}
+	return !*str && !*pat;
+}
+
+/**
+ * strglobmatch - glob expression pattern matching
+ * @str: the target string to match
+ * @pat: the pattern string to match
+ *
+ * This returns true if the @str matches @pat. @pat can includes wildcards
+ * ('*','?') and character classes ([CHARS], complementation and ranges are
+ * also supported). Also, this supports escape character ('\') to use special
+ * characters as normal character.
+ *
+ * Note: if @pat syntax is broken, this always returns false.
+ */
+bool strglobmatch(const char *str, const char *pat)
+{
+	return __match_glob(str, pat, false, false);
+}
+
+bool strglobmatch_nocase(const char *str, const char *pat)
+{
+	return __match_glob(str, pat, false, true);
+}
+
+/**
+ * strlazymatch - matching pattern strings lazily with glob pattern
+ * @str: the target string to match
+ * @pat: the pattern string to match
+ *
+ * This is similar to strglobmatch, except this ignores spaces in
+ * the target string.
+ */
+bool strlazymatch(const char *str, const char *pat)
+{
+	return __match_glob(str, pat, true, false);
+}
+
+/**
+ * strtailcmp - Compare the tail of two strings
+ * @s1: 1st string to be compared
+ * @s2: 2nd string to be compared
+ *
+ * Return 0 if whole of either string is same as another's tail part.
+ */
+int strtailcmp(const char *s1, const char *s2)
+{
+	int i1 = strlen(s1);
+	int i2 = strlen(s2);
+	while (--i1 >= 0 && --i2 >= 0) {
+		if (s1[i1] != s2[i2])
+			return s1[i1] - s2[i2];
+	}
+	return 0;
+}
+
+char *asprintf_expr_inout_ints(const char *var, bool in, size_t nints, int *ints)
+{
+	/*
+	 * FIXME: replace this with an expression using log10() when we
+	 * find a suitable implementation, maybe the one in the dvb drivers...
+	 *
+	 * "%s == %d || " = log10(MAXINT) * 2 + 8 chars for the operators
+	 */
+	size_t size = nints * 28 + 1; /* \0 */
+	size_t i, printed = 0;
+	char *expr = malloc(size);
+
+	if (expr) {
+		const char *or_and = "||", *eq_neq = "==";
+		char *e = expr;
+
+		if (!in) {
+			or_and = "&&";
+			eq_neq = "!=";
+		}
+
+		for (i = 0; i < nints; ++i) {
+			if (printed == size)
+				goto out_err_overflow;
+
+			if (i > 0)
+				printed += scnprintf(e + printed, size - printed, " %s ", or_and);
+			printed += scnprintf(e + printed, size - printed,
+					     "%s %s %d", var, eq_neq, ints[i]);
+		}
+	}
+
+	return expr;
+
+out_err_overflow:
+	free(expr);
+	return NULL;
+}
+
+/* Like strpbrk(), but not break if it is right after a backslash (escaped) */
+char *strpbrk_esc(char *str, const char *stopset)
+{
+	char *ptr;
+
+	do {
+		ptr = strpbrk(str, stopset);
+		if (!ptr) {
+			/* stopset not in str. */
+			break;
+		}
+		if (ptr == str) {
+			/* stopset character is first in str. */
+			break;
+		}
+		if (ptr == str + 1 && str[0] != '\\') {
+			/* stopset chacter is second and wasn't preceded by a '\'. */
+			break;
+		}
+		str = ptr + 1;
+	} while (ptr[-1] == '\\' && ptr[-2] != '\\');
+
+	return ptr;
+}
+
+/* Like strpbrk_esc(), but not break if it is quoted with single/double quotes */
+char *strpbrk_esq(char *str, const char *stopset)
+{
+	char *_stopset = NULL;
+	char *ptr;
+	const char *squote = "'";
+	const char *dquote = "\"";
+
+	if (asprintf(&_stopset, "%s%c%c", stopset, *squote, *dquote) < 0)
+		return NULL;
+
+	do {
+		ptr = strpbrk_esc(str, _stopset);
+		if (!ptr)
+			break;
+		if (*ptr == *squote)
+			ptr = strpbrk_esc(ptr + 1, squote);
+		else if (*ptr == *dquote)
+			ptr = strpbrk_esc(ptr + 1, dquote);
+		else
+			break;
+		str = ptr + 1;
+	} while (ptr);
+
+	free(_stopset);
+	return ptr;
+}
+
+/* Like strdup, but do not copy a single backslash */
+char *strdup_esc(const char *str)
+{
+	char *s, *d, *p, *ret = strdup(str);
+
+	if (!ret)
+		return NULL;
+
+	d = strchr(ret, '\\');
+	if (!d)
+		return ret;
+
+	s = d + 1;
+	do {
+		if (*s == '\0') {
+			*d = '\0';
+			break;
+		}
+		p = strchr(s + 1, '\\');
+		if (p) {
+			memmove(d, s, p - s);
+			d += p - s;
+			s = p + 1;
+		} else
+			memmove(d, s, strlen(s) + 1);
+	} while (p);
+
+	return ret;
+}
+
+/* Remove backslash right before quote and return next quote address. */
+static char *remove_consumed_esc(char *str, int len, int quote)
+{
+	char *ptr = str, *end = str + len;
+
+	while (*ptr != quote && ptr < end) {
+		if (*ptr == '\\' && *(ptr + 1) == quote) {
+			memmove(ptr, ptr + 1, end - (ptr + 1));
+			/* now *ptr is `quote`. */
+			end--;
+		}
+		ptr++;
+	}
+
+	return *ptr == quote ? ptr : NULL;
+}
+
+/*
+ * Like strdup_esc, but keep quoted string as it is (and single backslash
+ * before quote is removed). If there is no closed quote, return NULL.
+ */
+char *strdup_esq(const char *str)
+{
+	char *d, *ret;
+
+	/* If there is no quote, return normal strdup_esc() */
+	d = strpbrk_esc((char *)str, "\"'");
+	if (!d)
+		return strdup_esc(str);
+
+	ret = strdup(str);
+	if (!ret)
+		return NULL;
+
+	d = ret;
+	do {
+		d = strpbrk(d, "\\\"\'");
+		if (!d)
+			break;
+
+		if (*d == '"' || *d == '\'') {
+			/* This is non-escaped quote */
+			int quote = *d;
+			int len = strlen(d + 1) + 1;
+
+			/*
+			 * Remove the start quote and remove consumed escape (backslash
+			 * before quote) and remove the end quote. If there is no end
+			 * quote, it is the input error.
+			 */
+			memmove(d, d + 1, len);
+			d = remove_consumed_esc(d, len, quote);
+			if (!d)
+				goto error;
+			memmove(d, d + 1, strlen(d + 1) + 1);
+		}
+		if (*d == '\\') {
+			memmove(d, d + 1, strlen(d + 1) + 1);
+			if (*d == '\\') {
+				/* double backslash -- keep the second one. */
+				d++;
+			}
+		}
+	} while (*d != '\0');
+
+	return ret;
+
+error:
+	free(ret);
+	return NULL;
+}
+
+unsigned int hex(char c)
+{
+	if (c >= '0' && c <= '9')
+		return c - '0';
+	if (c >= 'a' && c <= 'f')
+		return c - 'a' + 10;
+	return c - 'A' + 10;
+}
+
+/*
+ * Replace all occurrences of character 'needle' in string 'haystack' with
+ * string 'replace'
+ *
+ * The new string could be longer so a new string is returned which must be
+ * freed.
+ */
+char *strreplace_chars(char needle, const char *haystack, const char *replace)
+{
+	int replace_len = strlen(replace);
+	char *new_s, *to;
+	const char *loc = strchr(haystack, needle);
+	const char *from = haystack;
+	int num = 0;
+
+	/* Count occurrences */
+	while (loc) {
+		loc = strchr(loc + 1, needle);
+		num++;
+	}
+
+	/* Allocate enough space for replacements and reset first location */
+	new_s = malloc(strlen(haystack) + (num * (replace_len - 1) + 1));
+	if (!new_s)
+		return NULL;
+	loc = strchr(haystack, needle);
+	to = new_s;
+
+	while (loc) {
+		/* Copy original string up to found char and update positions */
+		memcpy(to, from, 1 + loc - from);
+		to += loc - from;
+		from = loc + 1;
+
+		/* Copy replacement string and update positions */
+		memcpy(to, replace, replace_len);
+		to += replace_len;
+
+		/* needle next occurrence or end of string */
+		loc = strchr(from, needle);
+	}
+
+	/* Copy any remaining chars + null */
+	strcpy(to, from);
+
+	return new_s;
+}
-- 
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