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, 352 insertions, 0 deletions

diff --git a/scripts/dtc/fdtget.c b/scripts/dtc/fdtget.c
new file mode 100644
index 000000000..c922f8224
--- /dev/null
+++ b/scripts/dtc/fdtget.c
@@ -0,0 +1,352 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+ *
+ * Portions from U-Boot cmd_fdt.c (C) Copyright 2007
+ * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com
+ * Based on code written by:
+ *   Pantelis Antoniou <pantelis.antoniou@gmail.com> and
+ *   Matthew McClintock <msm@freescale.com>
+ */
+
+#include <assert.h>
+#include <ctype.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <libfdt.h>
+
+#include "util.h"
+
+enum display_mode {
+	MODE_SHOW_VALUE,	/* show values for node properties */
+	MODE_LIST_PROPS,	/* list the properties for a node */
+	MODE_LIST_SUBNODES,	/* list the subnodes of a node */
+};
+
+/* Holds information which controls our output and options */
+struct display_info {
+	int type;		/* data type (s/i/u/x or 0 for default) */
+	int size;		/* data size (1/2/4) */
+	enum display_mode mode;	/* display mode that we are using */
+	const char *default_val; /* default value if node/property not found */
+};
+
+static void report_error(const char *where, int err)
+{
+	fprintf(stderr, "Error at '%s': %s\n", where, fdt_strerror(err));
+}
+
+/**
+ * Displays data of a given length according to selected options
+ *
+ * If a specific data type is provided in disp, then this is used. Otherwise
+ * we try to guess the data type / size from the contents.
+ *
+ * @param disp		Display information / options
+ * @param data		Data to display
+ * @param len		Maximum length of buffer
+ * @return 0 if ok, -1 if data does not match format
+ */
+static int show_data(struct display_info *disp, const char *data, int len)
+{
+	int i, size;
+	const uint8_t *p = (const uint8_t *)data;
+	const char *s;
+	int value;
+	int is_string;
+	char fmt[3];
+
+	/* no data, don't print */
+	if (len == 0)
+		return 0;
+
+	is_string = (disp->type) == 's' ||
+		(!disp->type && util_is_printable_string(data, len));
+	if (is_string) {
+		if (data[len - 1] != '\0') {
+			fprintf(stderr, "Unterminated string\n");
+			return -1;
+		}
+		for (s = data; s - data < len; s += strlen(s) + 1) {
+			if (s != data)
+				printf(" ");
+			printf("%s", (const char *)s);
+		}
+		return 0;
+	}
+	size = disp->size;
+	if (size == -1) {
+		size = (len % 4) == 0 ? 4 : 1;
+	} else if (len % size) {
+		fprintf(stderr, "Property length must be a multiple of "
+				"selected data size\n");
+		return -1;
+	}
+	fmt[0] = '%';
+	fmt[1] = disp->type ? disp->type : 'd';
+	fmt[2] = '\0';
+	for (i = 0; i < len; i += size, p += size) {
+		if (i)
+			printf(" ");
+		value = size == 4 ? fdt32_to_cpu(*(const uint32_t *)p) :
+			size == 2 ? (*p << 8) | p[1] : *p;
+		printf(fmt, value);
+	}
+	return 0;
+}
+
+/**
+ * List all properties in a node, one per line.
+ *
+ * @param blob		FDT blob
+ * @param node		Node to display
+ * @return 0 if ok, or FDT_ERR... if not.
+ */
+static int list_properties(const void *blob, int node)
+{
+	const struct fdt_property *data;
+	const char *name;
+	int prop;
+
+	prop = fdt_first_property_offset(blob, node);
+	do {
+		/* Stop silently when there are no more properties */
+		if (prop < 0)
+			return prop == -FDT_ERR_NOTFOUND ? 0 : prop;
+		data = fdt_get_property_by_offset(blob, prop, NULL);
+		name = fdt_string(blob, fdt32_to_cpu(data->nameoff));
+		if (name)
+			puts(name);
+		prop = fdt_next_property_offset(blob, prop);
+	} while (1);
+}
+
+#define MAX_LEVEL	32		/* how deeply nested we will go */
+
+/**
+ * List all subnodes in a node, one per line
+ *
+ * @param blob		FDT blob
+ * @param node		Node to display
+ * @return 0 if ok, or FDT_ERR... if not.
+ */
+static int list_subnodes(const void *blob, int node)
+{
+	int nextoffset;		/* next node offset from libfdt */
+	uint32_t tag;		/* current tag */
+	int level = 0;		/* keep track of nesting level */
+	const char *pathp;
+	int depth = 1;		/* the assumed depth of this node */
+
+	while (level >= 0) {
+		tag = fdt_next_tag(blob, node, &nextoffset);
+		switch (tag) {
+		case FDT_BEGIN_NODE:
+			pathp = fdt_get_name(blob, node, NULL);
+			if (level <= depth) {
+				if (pathp == NULL)
+					pathp = "/* NULL pointer error */";
+				if (*pathp == '\0')
+					pathp = "/";	/* root is nameless */
+				if (level == 1)
+					puts(pathp);
+			}
+			level++;
+			if (level >= MAX_LEVEL) {
+				printf("Nested too deep, aborting.\n");
+				return 1;
+			}
+			break;
+		case FDT_END_NODE:
+			level--;
+			if (level == 0)
+				level = -1;		/* exit the loop */
+			break;
+		case FDT_END:
+			return 1;
+		case FDT_PROP:
+			break;
+		default:
+			if (level <= depth)
+				printf("Unknown tag 0x%08X\n", tag);
+			return 1;
+		}
+		node = nextoffset;
+	}
+	return 0;
+}
+
+/**
+ * Show the data for a given node (and perhaps property) according to the
+ * display option provided.
+ *
+ * @param blob		FDT blob
+ * @param disp		Display information / options
+ * @param node		Node to display
+ * @param property	Name of property to display, or NULL if none
+ * @return 0 if ok, -ve on error
+ */
+static int show_data_for_item(const void *blob, struct display_info *disp,
+		int node, const char *property)
+{
+	const void *value = NULL;
+	int len, err = 0;
+
+	switch (disp->mode) {
+	case MODE_LIST_PROPS:
+		err = list_properties(blob, node);
+		break;
+
+	case MODE_LIST_SUBNODES:
+		err = list_subnodes(blob, node);
+		break;
+
+	default:
+		assert(property);
+		value = fdt_getprop(blob, node, property, &len);
+		if (value) {
+			if (show_data(disp, value, len))
+				err = -1;
+			else
+				printf("\n");
+		} else if (disp->default_val) {
+			puts(disp->default_val);
+		} else {
+			report_error(property, len);
+			err = -1;
+		}
+		break;
+	}
+
+	return err;
+}
+
+/**
+ * Run the main fdtget operation, given a filename and valid arguments
+ *
+ * @param disp		Display information / options
+ * @param filename	Filename of blob file
+ * @param arg		List of arguments to process
+ * @param arg_count	Number of arguments
+ * @param return 0 if ok, -ve on error
+ */
+static int do_fdtget(struct display_info *disp, const char *filename,
+		     char **arg, int arg_count, int args_per_step)
+{
+	char *blob;
+	const char *prop;
+	int i, node;
+
+	blob = utilfdt_read(filename);
+	if (!blob)
+		return -1;
+
+	for (i = 0; i + args_per_step <= arg_count; i += args_per_step) {
+		node = fdt_path_offset(blob, arg[i]);
+		if (node < 0) {
+			if (disp->default_val) {
+				puts(disp->default_val);
+				continue;
+			} else {
+				report_error(arg[i], node);
+				return -1;
+			}
+		}
+		prop = args_per_step == 1 ? NULL : arg[i + 1];
+
+		if (show_data_for_item(blob, disp, node, prop))
+			return -1;
+	}
+	return 0;
+}
+
+static const char *usage_msg =
+	"fdtget - read values from device tree\n"
+	"\n"
+	"Each value is printed on a new line.\n\n"
+	"Usage:\n"
+	"	fdtget <options> <dt file> [<node> <property>]...\n"
+	"	fdtget -p <options> <dt file> [<node> ]...\n"
+	"Options:\n"
+	"\t-t <type>\tType of data\n"
+	"\t-p\t\tList properties for each node\n"
+	"\t-l\t\tList subnodes for each node\n"
+	"\t-d\t\tDefault value to display when the property is "
+			"missing\n"
+	"\t-h\t\tPrint this help\n\n"
+	USAGE_TYPE_MSG;
+
+static void usage(const char *msg)
+{
+	if (msg)
+		fprintf(stderr, "Error: %s\n\n", msg);
+
+	fprintf(stderr, "%s", usage_msg);
+	exit(2);
+}
+
+int main(int argc, char *argv[])
+{
+	char *filename = NULL;
+	struct display_info disp;
+	int args_per_step = 2;
+
+	/* set defaults */
+	memset(&disp, '\0', sizeof(disp));
+	disp.size = -1;
+	disp.mode = MODE_SHOW_VALUE;
+	for (;;) {
+		int c = getopt(argc, argv, "d:hlpt:");
+		if (c == -1)
+			break;
+
+		switch (c) {
+		case 'h':
+		case '?':
+			usage(NULL);
+
+		case 't':
+			if (utilfdt_decode_type(optarg, &disp.type,
+					&disp.size))
+				usage("Invalid type string");
+			break;
+
+		case 'p':
+			disp.mode = MODE_LIST_PROPS;
+			args_per_step = 1;
+			break;
+
+		case 'l':
+			disp.mode = MODE_LIST_SUBNODES;
+			args_per_step = 1;
+			break;
+
+		case 'd':
+			disp.default_val = optarg;
+			break;
+		}
+	}
+
+	if (optind < argc)
+		filename = argv[optind++];
+	if (!filename)
+		usage("Missing filename");
+
+	argv += optind;
+	argc -= optind;
+
+	/* Allow no arguments, and silently succeed */
+	if (!argc)
+		return 0;
+
+	/* Check for node, property arguments */
+	if (args_per_step == 2 && (argc % 2))
+		usage("Must have an even number of arguments");
+
+	if (do_fdtget(&disp, filename, argv, argc, args_per_step))
+		return 1;
+	return 0;
+}