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, 582 insertions, 0 deletions

diff --git a/tools/bootconfig/main.c b/tools/bootconfig/main.c
new file mode 100644
index 000000000..7dc9fff9b
--- /dev/null
+++ b/tools/bootconfig/main.c
@@ -0,0 +1,582 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Boot config tool for initrd image
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <endian.h>
+#include <assert.h>
+
+#include <linux/bootconfig.h>
+
+#define pr_err(fmt, ...) fprintf(stderr, fmt, ##__VA_ARGS__)
+
+/* Bootconfig footer is [size][csum][BOOTCONFIG_MAGIC]. */
+#define BOOTCONFIG_FOOTER_SIZE	\
+	(sizeof(uint32_t) * 2 + BOOTCONFIG_MAGIC_LEN)
+
+static int xbc_show_value(struct xbc_node *node, bool semicolon)
+{
+	const char *val, *eol;
+	char q;
+	int i = 0;
+
+	eol = semicolon ? ";\n" : "\n";
+	xbc_array_for_each_value(node, val) {
+		if (strchr(val, '"'))
+			q = '\'';
+		else
+			q = '"';
+		printf("%c%s%c%s", q, val, q, xbc_node_is_array(node) ? ", " : eol);
+		i++;
+	}
+	return i;
+}
+
+static void xbc_show_compact_tree(void)
+{
+	struct xbc_node *node, *cnode = NULL, *vnode;
+	int depth = 0, i;
+
+	node = xbc_root_node();
+	while (node && xbc_node_is_key(node)) {
+		for (i = 0; i < depth; i++)
+			printf("\t");
+		if (!cnode)
+			cnode = xbc_node_get_child(node);
+		while (cnode && xbc_node_is_key(cnode) && !cnode->next) {
+			vnode = xbc_node_get_child(cnode);
+			/*
+			 * If @cnode has value and subkeys, this
+			 * should show it as below.
+			 *
+			 * key(@node) {
+			 *      key(@cnode) = value;
+			 *      key(@cnode) {
+			 *          subkeys;
+			 *      }
+			 * }
+			 */
+			if (vnode && xbc_node_is_value(vnode) && vnode->next)
+				break;
+			printf("%s.", xbc_node_get_data(node));
+			node = cnode;
+			cnode = vnode;
+		}
+		if (cnode && xbc_node_is_key(cnode)) {
+			printf("%s {\n", xbc_node_get_data(node));
+			depth++;
+			node = cnode;
+			cnode = NULL;
+			continue;
+		} else if (cnode && xbc_node_is_value(cnode)) {
+			printf("%s = ", xbc_node_get_data(node));
+			xbc_show_value(cnode, true);
+			/*
+			 * If @node has value and subkeys, continue
+			 * looping on subkeys with same node.
+			 */
+			if (cnode->next) {
+				cnode = xbc_node_get_next(cnode);
+				continue;
+			}
+		} else {
+			printf("%s;\n", xbc_node_get_data(node));
+		}
+		cnode = NULL;
+
+		if (node->next) {
+			node = xbc_node_get_next(node);
+			continue;
+		}
+		while (!node->next) {
+			node = xbc_node_get_parent(node);
+			if (!node)
+				return;
+			if (!xbc_node_get_child(node)->next)
+				continue;
+			if (depth) {
+				depth--;
+				for (i = 0; i < depth; i++)
+					printf("\t");
+				printf("}\n");
+			}
+		}
+		node = xbc_node_get_next(node);
+	}
+}
+
+static void xbc_show_list(void)
+{
+	char key[XBC_KEYLEN_MAX];
+	struct xbc_node *leaf;
+	const char *val;
+	int ret;
+
+	xbc_for_each_key_value(leaf, val) {
+		ret = xbc_node_compose_key(leaf, key, XBC_KEYLEN_MAX);
+		if (ret < 0) {
+			fprintf(stderr, "Failed to compose key %d\n", ret);
+			break;
+		}
+		printf("%s = ", key);
+		if (!val || val[0] == '\0') {
+			printf("\"\"\n");
+			continue;
+		}
+		xbc_show_value(xbc_node_get_child(leaf), false);
+	}
+}
+
+#define PAGE_SIZE	4096
+
+static int load_xbc_fd(int fd, char **buf, int size)
+{
+	int ret;
+
+	*buf = malloc(size + 1);
+	if (!*buf)
+		return -ENOMEM;
+
+	ret = read(fd, *buf, size);
+	if (ret < 0)
+		return -errno;
+	(*buf)[size] = '\0';
+
+	return ret;
+}
+
+/* Return the read size or -errno */
+static int load_xbc_file(const char *path, char **buf)
+{
+	struct stat stat;
+	int fd, ret;
+
+	fd = open(path, O_RDONLY);
+	if (fd < 0)
+		return -errno;
+	ret = fstat(fd, &stat);
+	if (ret < 0) {
+		ret = -errno;
+		close(fd);
+		return ret;
+	}
+
+	ret = load_xbc_fd(fd, buf, stat.st_size);
+
+	close(fd);
+
+	return ret;
+}
+
+static int pr_errno(const char *msg, int err)
+{
+	pr_err("%s: %d\n", msg, err);
+	return err;
+}
+
+static int load_xbc_from_initrd(int fd, char **buf)
+{
+	struct stat stat;
+	int ret;
+	uint32_t size = 0, csum = 0, rcsum;
+	char magic[BOOTCONFIG_MAGIC_LEN];
+	const char *msg;
+
+	ret = fstat(fd, &stat);
+	if (ret < 0)
+		return -errno;
+
+	if (stat.st_size < BOOTCONFIG_FOOTER_SIZE)
+		return 0;
+
+	if (lseek(fd, -(off_t)BOOTCONFIG_MAGIC_LEN, SEEK_END) < 0)
+		return pr_errno("Failed to lseek for magic", -errno);
+
+	if (read(fd, magic, BOOTCONFIG_MAGIC_LEN) < 0)
+		return pr_errno("Failed to read", -errno);
+
+	/* Check the bootconfig magic bytes */
+	if (memcmp(magic, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN) != 0)
+		return 0;
+
+	if (lseek(fd, -(off_t)BOOTCONFIG_FOOTER_SIZE, SEEK_END) < 0)
+		return pr_errno("Failed to lseek for size", -errno);
+
+	if (read(fd, &size, sizeof(uint32_t)) < 0)
+		return pr_errno("Failed to read size", -errno);
+	size = le32toh(size);
+
+	if (read(fd, &csum, sizeof(uint32_t)) < 0)
+		return pr_errno("Failed to read checksum", -errno);
+	csum = le32toh(csum);
+
+	/* Wrong size error  */
+	if (stat.st_size < size + BOOTCONFIG_FOOTER_SIZE) {
+		pr_err("bootconfig size is too big\n");
+		return -E2BIG;
+	}
+
+	if (lseek(fd, stat.st_size - (size + BOOTCONFIG_FOOTER_SIZE),
+		  SEEK_SET) < 0)
+		return pr_errno("Failed to lseek", -errno);
+
+	ret = load_xbc_fd(fd, buf, size);
+	if (ret < 0)
+		return ret;
+
+	/* Wrong Checksum */
+	rcsum = xbc_calc_checksum(*buf, size);
+	if (csum != rcsum) {
+		pr_err("checksum error: %u != %u\n", csum, rcsum);
+		return -EINVAL;
+	}
+
+	ret = xbc_init(*buf, size, &msg, NULL);
+	/* Wrong data */
+	if (ret < 0) {
+		pr_err("parse error: %s.\n", msg);
+		return ret;
+	}
+
+	return size;
+}
+
+static void show_xbc_error(const char *data, const char *msg, int pos)
+{
+	int lin = 1, col, i;
+
+	if (pos < 0) {
+		pr_err("Error: %s.\n", msg);
+		return;
+	}
+
+	/* Note that pos starts from 0 but lin and col should start from 1. */
+	col = pos + 1;
+	for (i = 0; i < pos; i++) {
+		if (data[i] == '\n') {
+			lin++;
+			col = pos - i;
+		}
+	}
+	pr_err("Parse Error: %s at %d:%d\n", msg, lin, col);
+
+}
+
+static int init_xbc_with_error(char *buf, int len)
+{
+	char *copy = strdup(buf);
+	const char *msg;
+	int ret, pos;
+
+	if (!copy)
+		return -ENOMEM;
+
+	ret = xbc_init(buf, len, &msg, &pos);
+	if (ret < 0)
+		show_xbc_error(copy, msg, pos);
+	free(copy);
+
+	return ret;
+}
+
+static int show_xbc_kernel_cmdline(void)
+{
+	struct xbc_node *root;
+	char *buf = NULL;
+	int len, ret;
+
+	root = xbc_find_node("kernel");
+	if (!root)
+		return 0;	/* no kernel.* keys: emit empty output */
+
+	len = xbc_snprint_cmdline(NULL, 0, root);
+	if (len < 0) {
+		pr_err("Failed to size cmdline output: %d\n", len);
+		return len;
+	}
+	if (len == 0)
+		return 0;
+
+	buf = malloc(len + 1);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = xbc_snprint_cmdline(buf, len + 1, root);
+	if (ret < 0) {
+		pr_err("Failed to render cmdline output: %d\n", ret);
+		free(buf);
+		return ret;
+	}
+
+	fputs(buf, stdout);
+	free(buf);
+	return 0;
+}
+
+static int show_xbc(const char *path, bool list, bool render_cmdline)
+{
+	int ret, fd;
+	char *buf = NULL;
+	struct stat st;
+
+	ret = stat(path, &st);
+	if (ret < 0) {
+		ret = -errno;
+		pr_err("Failed to stat %s: %d\n", path, ret);
+		return ret;
+	}
+
+	fd = open(path, O_RDONLY);
+	if (fd < 0) {
+		ret = -errno;
+		pr_err("Failed to open initrd %s: %d\n", path, ret);
+		return ret;
+	}
+
+	ret = load_xbc_from_initrd(fd, &buf);
+	close(fd);
+	if (ret < 0) {
+		pr_err("Failed to load a boot config from initrd: %d\n", ret);
+		goto out;
+	}
+	/* Assume a bootconfig file if it is enough small */
+	if (ret == 0 && st.st_size <= XBC_DATA_MAX) {
+		ret = load_xbc_file(path, &buf);
+		if (ret < 0) {
+			pr_err("Failed to load a boot config: %d\n", ret);
+			goto out;
+		}
+		if (init_xbc_with_error(buf, ret) < 0)
+			goto out;
+	}
+	if (render_cmdline)
+		ret = show_xbc_kernel_cmdline();
+	else if (list)
+		xbc_show_list();
+	else
+		xbc_show_compact_tree();
+	if (ret > 0)
+		ret = 0;
+out:
+	free(buf);
+
+	return ret;
+}
+
+static int delete_xbc(const char *path)
+{
+	struct stat stat;
+	int ret = 0, fd, size;
+	char *buf = NULL;
+
+	fd = open(path, O_RDWR);
+	if (fd < 0) {
+		ret = -errno;
+		pr_err("Failed to open initrd %s: %d\n", path, ret);
+		return ret;
+	}
+
+	size = load_xbc_from_initrd(fd, &buf);
+	if (size < 0) {
+		ret = size;
+		pr_err("Failed to load a boot config from initrd: %d\n", ret);
+	} else if (size > 0) {
+		ret = fstat(fd, &stat);
+		if (!ret)
+			ret = ftruncate(fd, stat.st_size
+					- size - BOOTCONFIG_FOOTER_SIZE);
+		if (ret)
+			ret = -errno;
+	} /* Ignore if there is no boot config in initrd */
+
+	close(fd);
+	free(buf);
+
+	return ret;
+}
+
+static int apply_xbc(const char *path, const char *xbc_path)
+{
+	struct {
+		uint32_t size;
+		uint32_t csum;
+		char magic[BOOTCONFIG_MAGIC_LEN];
+	} footer;
+	char *buf, *data;
+	size_t total_size;
+	struct stat stat;
+	const char *msg;
+	uint32_t size, csum;
+	int pos, pad;
+	int ret, fd;
+
+	ret = load_xbc_file(xbc_path, &buf);
+	if (ret < 0) {
+		pr_err("Failed to load %s : %d\n", xbc_path, ret);
+		return ret;
+	}
+	size = strlen(buf) + 1;
+	csum = xbc_calc_checksum(buf, size);
+
+	/* Backup the bootconfig data */
+	data = calloc(size + BOOTCONFIG_ALIGN + BOOTCONFIG_FOOTER_SIZE, 1);
+	if (!data) {
+		free(buf);
+		return -ENOMEM;
+	}
+	memcpy(data, buf, size);
+
+	/* Check the data format */
+	ret = xbc_init(buf, size, &msg, &pos);
+	if (ret < 0) {
+		show_xbc_error(data, msg, pos);
+		free(data);
+		free(buf);
+
+		return ret;
+	}
+	printf("Apply %s to %s\n", xbc_path, path);
+	xbc_get_info(&ret, NULL);
+	printf("\tNumber of nodes: %d\n", ret);
+	printf("\tSize: %u bytes\n", (unsigned int)size);
+	printf("\tChecksum: %u\n", (unsigned int)csum);
+
+	/* TODO: Check the options by schema */
+	xbc_exit();
+	free(buf);
+
+	/* Remove old boot config if exists */
+	ret = delete_xbc(path);
+	if (ret < 0) {
+		pr_err("Failed to delete previous boot config: %d\n", ret);
+		free(data);
+		return ret;
+	}
+
+	/* Apply new one */
+	fd = open(path, O_RDWR | O_APPEND);
+	if (fd < 0) {
+		ret = -errno;
+		pr_err("Failed to open %s: %d\n", path, ret);
+		free(data);
+		return ret;
+	}
+	/* TODO: Ensure the @path is initramfs/initrd image */
+	if (fstat(fd, &stat) < 0) {
+		ret = -errno;
+		pr_err("Failed to get the size of %s\n", path);
+		goto out;
+	}
+
+	/* To align up the total size to BOOTCONFIG_ALIGN, get padding size */
+	total_size = stat.st_size + size + BOOTCONFIG_FOOTER_SIZE;
+	pad = ((total_size + BOOTCONFIG_ALIGN - 1) & (~BOOTCONFIG_ALIGN_MASK)) - total_size;
+	size += pad;
+
+	/* Add a footer */
+	footer.size = htole32(size);
+	footer.csum = htole32(csum);
+	memcpy(footer.magic, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN);
+	static_assert(sizeof(footer) == BOOTCONFIG_FOOTER_SIZE);
+	memcpy(data + size, &footer, BOOTCONFIG_FOOTER_SIZE);
+
+	total_size = size + BOOTCONFIG_FOOTER_SIZE;
+
+	ret = write(fd, data, total_size);
+	if (ret < total_size) {
+		if (ret < 0)
+			ret = -errno;
+		pr_err("Failed to apply a boot config: %d\n", ret);
+		if (ret >= 0)
+			goto out_rollback;
+	} else
+		ret = 0;
+
+out:
+	close(fd);
+	free(data);
+
+	return ret;
+
+out_rollback:
+	/* Map the partial write to -ENOSPC */
+	if (ret >= 0)
+		ret = -ENOSPC;
+	if (ftruncate(fd, stat.st_size) < 0) {
+		ret = -errno;
+		pr_err("Failed to rollback the write error: %d\n", ret);
+		pr_err("The initrd %s may be corrupted. Recommend to rebuild.\n", path);
+	}
+	goto out;
+}
+
+static int usage(void)
+{
+	printf("Usage: bootconfig [OPTIONS] <INITRD>\n"
+		"Or     bootconfig <CONFIG>\n"
+		" Apply, delete or show boot config to initrd.\n"
+		" Options:\n"
+		"		-a <config>: Apply boot config to initrd\n"
+		"		-d : Delete boot config file from initrd\n"
+		"		-l : list boot config in initrd or file\n"
+		"		-C : render the kernel.* subtree as a flat cmdline\n"
+		"		     string (suitable for embedding in a kernel image)\n"
+		"		     and print it to stdout\n\n"
+		" If no option is given, show the bootconfig in the given file.\n");
+	return -1;
+}
+
+int main(int argc, char **argv)
+{
+	char *path = NULL;
+	char *apply = NULL;
+	bool render_cmdline = false;
+	bool delete = false, list = false;
+	int opt;
+
+	while ((opt = getopt(argc, argv, "hda:lC")) != -1) {
+		switch (opt) {
+		case 'd':
+			delete = true;
+			break;
+		case 'a':
+			apply = optarg;
+			break;
+		case 'l':
+			list = true;
+			break;
+		case 'C':
+			render_cmdline = true;
+			break;
+		case 'h':
+		default:
+			return usage();
+		}
+	}
+
+	if ((!!apply + !!delete + !!list + !!render_cmdline) > 1) {
+		pr_err("Error: You can give one of -a, -d, -l or -C at once.\n");
+		return usage();
+	}
+
+	if (optind >= argc) {
+		pr_err("Error: No initrd is specified.\n");
+		return usage();
+	}
+
+	path = argv[optind];
+
+	if (apply)
+		return apply_xbc(path, apply);
+	else if (delete)
+		return delete_xbc(path);
+
+	return show_xbc(path, list, render_cmdline);
+}