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, 597 insertions, 0 deletions

diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
new file mode 100644
index 000000000..33fd1b820
--- /dev/null
+++ b/tools/perf/util/data.c
@@ -0,0 +1,597 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/zalloc.h>
+#include <linux/err.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <asm/bug.h>
+#include <dirent.h>
+
+#include "data.h"
+#include "util.h" // rm_rf_perf_data()
+#include "debug.h"
+#include "header.h"
+#include "rlimit.h"
+#include <internal/lib.h>
+
+static void perf_data_file__close(struct perf_data_file *file)
+{
+	if (file->use_stdio) {
+		if (file->fptr) {
+			fclose(file->fptr);
+			file->fptr = NULL;
+		}
+	} else {
+		close(file->fd);
+		file->fd = -1;
+	}
+	zfree(&file->path);
+}
+
+static void close_dir(struct perf_data_file *files, int nr)
+{
+	while (--nr >= 0)
+		perf_data_file__close(&files[nr]);
+
+	free(files);
+}
+
+void perf_data__close_dir(struct perf_data *data)
+{
+	close_dir(data->dir.files, data->dir.nr);
+	data->dir.files = NULL;
+	data->dir.nr = 0;
+}
+
+int perf_data__create_dir(struct perf_data *data, int nr)
+{
+	enum rlimit_action set_rlimit = NO_CHANGE;
+	struct perf_data_file *files = NULL;
+	int i, ret;
+
+	if (WARN_ON(!data->is_dir))
+		return -EINVAL;
+
+	files = calloc(nr, sizeof(*files));
+	if (!files)
+		return -ENOMEM;
+
+	for (i = 0; i < nr; i++) {
+		struct perf_data_file *file = &files[i];
+
+		ret = asprintf(&file->path, "%s/data.%d", data->path, i);
+		if (ret < 0) {
+			ret = -ENOMEM;
+			goto out_err;
+		}
+
+retry_open:
+		ret = open(file->path, O_RDWR|O_CREAT|O_TRUNC, S_IRUSR|S_IWUSR);
+		if (ret < 0) {
+			/*
+			 * If using parallel threads to collect data,
+			 * perf record needs at least 6 fds per CPU.
+			 * When we run out of them try to increase the limits.
+			 */
+			if (errno == EMFILE && rlimit__increase_nofile(&set_rlimit))
+				goto retry_open;
+
+			ret = -errno;
+			goto out_err;
+		}
+		set_rlimit = NO_CHANGE;
+
+		file->fd = ret;
+	}
+
+	data->dir.version = PERF_DIR_VERSION;
+	data->dir.files   = files;
+	data->dir.nr      = nr;
+	return 0;
+
+out_err:
+	close_dir(files, i);
+	return ret;
+}
+
+int perf_data__open_dir(struct perf_data *data)
+{
+	struct perf_data_file *files = NULL;
+	struct dirent *dent;
+	int ret = -1;
+	DIR *dir;
+	int nr = 0;
+
+	/*
+	 * Directory containing a single regular perf data file which is already
+	 * open, means there is nothing more to do here.
+	 */
+	if (perf_data__is_single_file(data))
+		return 0;
+
+	if (WARN_ON(!data->is_dir))
+		return -EINVAL;
+
+	/* The version is provided by DIR_FORMAT feature. */
+	if (WARN_ON(data->dir.version != PERF_DIR_VERSION))
+		return -1;
+
+	dir = opendir(data->path);
+	if (!dir)
+		return -EINVAL;
+
+	while ((dent = readdir(dir)) != NULL) {
+		struct perf_data_file *file;
+		char path[PATH_MAX];
+		struct stat st;
+
+		snprintf(path, sizeof(path), "%s/%s", data->path, dent->d_name);
+		if (stat(path, &st))
+			continue;
+
+		if (!S_ISREG(st.st_mode) || strncmp(dent->d_name, "data.", 5))
+			continue;
+
+		ret = -ENOMEM;
+
+		file = realloc(files, (nr + 1) * sizeof(*files));
+		if (!file)
+			goto out_err;
+
+		files = file;
+		file = &files[nr++];
+
+		*file = (struct perf_data_file){
+			.path = strdup(path),
+			.fd = -1,
+			.size = st.st_size,
+			.use_stdio = false,
+		};
+		if (!file->path)
+			goto out_err;
+
+		ret = open(file->path, O_RDONLY);
+		if (ret < 0) {
+			ret = -errno;
+			goto out_err;
+		}
+		file->fd = ret;
+	}
+
+	closedir(dir);
+	if (!files)
+		return -EINVAL;
+
+	data->dir.files = files;
+	data->dir.nr    = nr;
+	return 0;
+
+out_err:
+	closedir(dir);
+	close_dir(files, nr);
+	return ret;
+}
+
+static bool check_pipe(struct perf_data *data)
+{
+	struct stat st;
+	bool is_pipe = false;
+	int fd = perf_data__is_read(data) ?
+		 STDIN_FILENO : STDOUT_FILENO;
+
+	if (!data->path) {
+		if (!fstat(fd, &st) && S_ISFIFO(st.st_mode))
+			is_pipe = true;
+	} else {
+		if (!strcmp(data->path, "-"))
+			is_pipe = true;
+	}
+
+	if (is_pipe) {
+		if (data->file.use_stdio) {
+			const char *mode;
+
+			mode = perf_data__is_read(data) ? "r" : "w";
+			data->file.fptr = fdopen(fd, mode);
+
+			if (data->file.fptr == NULL) {
+				data->file.fd = fd;
+				data->file.use_stdio = false;
+			}
+
+		/*
+		 * When is_pipe and data->file.fd is given, use given fd
+		 * instead of STDIN_FILENO or STDOUT_FILENO
+		 */
+		} else if (data->file.fd <= 0) {
+			data->file.fd = fd;
+		}
+	}
+
+	return data->is_pipe = is_pipe;
+}
+
+static int check_backup(struct perf_data *data)
+{
+	struct stat st;
+
+	if (perf_data__is_read(data))
+		return 0;
+
+	if (!stat(data->path, &st) && st.st_size) {
+		char oldname[PATH_MAX];
+		int ret;
+
+		snprintf(oldname, sizeof(oldname), "%s.old",
+			 data->path);
+
+		ret = rm_rf_perf_data(oldname);
+		if (ret) {
+			if (ret == -2)
+				pr_err("Can't remove old data: Unknown file found (%s)\n", oldname);
+			else
+				pr_err("Can't remove old data: %m (%s)\n", oldname);
+			return -1;
+		}
+
+		if (rename(data->path, oldname)) {
+			pr_err("Can't move data: %m (%s to %s)\n", data->path, oldname);
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+static bool is_dir(struct perf_data *data)
+{
+	struct stat st;
+
+	if (stat(data->path, &st))
+		return false;
+
+	return (st.st_mode & S_IFMT) == S_IFDIR;
+}
+
+static int open_file_read(struct perf_data *data)
+{
+	int flags = data->in_place_update ? O_RDWR : O_RDONLY;
+	struct stat st;
+	int fd;
+
+	fd = open(data->file.path, flags);
+	if (fd < 0) {
+		int err = errno;
+
+		pr_err("failed to open %s: %m", data->file.path);
+		if (err == ENOENT && !strcmp(data->file.path, "perf.data"))
+			pr_err("  (try 'perf record' first)");
+		pr_err("\n");
+		return -err;
+	}
+
+	if (fstat(fd, &st) < 0)
+		goto out_close;
+
+	if (!data->force && st.st_uid && (st.st_uid != geteuid())) {
+		pr_err("File %s not owned by current user or root (use -f to override)\n",
+		       data->file.path);
+		goto out_close;
+	}
+
+	if (!st.st_size) {
+		pr_info("zero-sized data (%s), nothing to do!\n",
+			data->file.path);
+		goto out_close;
+	}
+
+	data->file.size = st.st_size;
+	return fd;
+
+ out_close:
+	close(fd);
+	return -1;
+}
+
+static int open_file_write(struct perf_data *data)
+{
+	int fd = open(data->file.path, O_CREAT|O_RDWR|O_TRUNC|O_CLOEXEC, S_IRUSR|S_IWUSR);
+
+	if (fd < 0)
+		pr_err("failed to open %s : %m\n", data->file.path);
+
+	return fd;
+}
+
+static int open_file(struct perf_data *data)
+{
+	int fd;
+
+	fd = perf_data__is_read(data) ?
+	     open_file_read(data) : open_file_write(data);
+
+	if (fd < 0) {
+		zfree(&data->file.path);
+		return -1;
+	}
+
+	data->file.fd = fd;
+	return 0;
+}
+
+static int open_file_dup(struct perf_data *data)
+{
+	data->file.path = strdup(data->path);
+	if (!data->file.path)
+		return -ENOMEM;
+
+	return open_file(data);
+}
+
+static int open_dir(struct perf_data *data)
+{
+	int ret;
+
+	/*
+	 * So far we open only the header, so we can read the data version and
+	 * layout.
+	 */
+	if (asprintf(&data->file.path, "%s/data", data->path) < 0)
+		return -1;
+
+	if (perf_data__is_write(data) && mkdir(data->path, 0700) < 0) {
+		zfree(&data->file.path);
+		return -1;
+	}
+
+	ret = open_file(data);
+
+	/* Cleanup whatever we managed to create so far. */
+	if (ret && perf_data__is_write(data))
+		rm_rf_perf_data(data->path);
+
+	return ret;
+}
+
+int perf_data__open(struct perf_data *data)
+{
+	int ret;
+
+	if (data->open)
+		return 0;
+
+	if (check_pipe(data)) {
+		data->open = true;
+		return 0;
+	}
+
+	/* currently it allows stdio for pipe only */
+	data->file.use_stdio = false;
+
+	if (!data->path)
+		data->path = "perf.data";
+
+	if (check_backup(data))
+		return -1;
+
+	if (perf_data__is_read(data))
+		data->is_dir = is_dir(data);
+
+	ret = perf_data__is_dir(data) ? open_dir(data) : open_file_dup(data);
+
+	if (!ret)
+		data->open = true;
+
+	return ret;
+}
+
+void perf_data__close(struct perf_data *data)
+{
+	if (!data->open)
+		return;
+
+	if (perf_data__is_dir(data))
+		perf_data__close_dir(data);
+
+	perf_data_file__close(&data->file);
+	data->open = false;
+}
+
+static ssize_t perf_data_file__read(struct perf_data_file *file, void *buf, size_t size)
+{
+	if (file->use_stdio) {
+		if (fread(buf, size, 1, file->fptr) == 1)
+			return size;
+		return feof(file->fptr) ? 0 : -1;
+	}
+	return readn(file->fd, buf, size);
+}
+
+ssize_t perf_data__read(struct perf_data *data, void *buf, size_t size)
+{
+	return perf_data_file__read(&data->file, buf, size);
+}
+
+ssize_t perf_data_file__write(struct perf_data_file *file,
+			      void *buf, size_t size)
+{
+	if (file->use_stdio) {
+		if (fwrite(buf, size, /*nmemb=*/1, file->fptr) == 1)
+			return size;
+		return -1;
+	}
+	return writen(file->fd, buf, size);
+}
+
+ssize_t perf_data__write(struct perf_data *data,
+			 void *buf, size_t size)
+{
+	return perf_data_file__write(&data->file, buf, size);
+}
+
+off_t perf_data_file__seek(struct perf_data_file *file, off_t offset, int whence)
+{
+	if (file->use_stdio) {
+		off_t res = fseeko(file->fptr, offset, whence);
+
+		return res < 0 ? -1 : ftello(file->fptr);
+	}
+	return lseek(file->fd, offset, whence);
+}
+
+off_t perf_data__seek(struct perf_data *data, off_t offset, int whence)
+{
+	/* Note, a pipe fd will fail with -1 with errno of ESPIPE. */
+	return perf_data_file__seek(&data->file, offset, whence);
+}
+
+int perf_data__switch(struct perf_data *data,
+		      const char *postfix,
+		      size_t pos, bool at_exit,
+		      char **new_filepath)
+{
+	int ret;
+
+	if (perf_data__is_read(data))
+		return -EINVAL;
+
+	if (asprintf(new_filepath, "%s.%s", data->path, postfix) < 0)
+		return -ENOMEM;
+
+	/*
+	 * Only fire a warning, don't return error, continue fill
+	 * original file.
+	 */
+	if (rename(data->path, *new_filepath))
+		pr_warning("Failed to rename %s to %s\n", data->path, *new_filepath);
+
+	if (!at_exit) {
+		perf_data_file__close(&data->file);
+		data->open = false;
+		ret = perf_data__open(data);
+		if (ret < 0)
+			goto out;
+
+		if (perf_data__seek(data, pos, SEEK_SET) == (off_t)-1) {
+			ret = -errno;
+			pr_debug("Failed to seek to %zu: %m", pos);
+			goto out;
+		}
+	}
+	ret = perf_data__fd(data);
+out:
+	return ret;
+}
+
+unsigned long perf_data__size(struct perf_data *data)
+{
+	u64 size = data->file.size;
+	int i;
+
+	if (perf_data__is_single_file(data))
+		return size;
+
+	for (i = 0; i < data->dir.nr; i++) {
+		struct perf_data_file *file = &data->dir.files[i];
+
+		size += file->size;
+	}
+
+	return size;
+}
+
+int perf_data__make_kcore_dir(struct perf_data *data, char *buf, size_t buf_sz)
+{
+	int ret;
+
+	if (!data->is_dir)
+		return -1;
+
+	ret = snprintf(buf, buf_sz, "%s/kcore_dir", data->path);
+	if (ret < 0 || (size_t)ret >= buf_sz)
+		return -1;
+
+	return mkdir(buf, S_IRWXU);
+}
+
+bool has_kcore_dir(const char *path)
+{
+	struct dirent *d = ERR_PTR(-EINVAL);
+	const char *name = "kcore_dir";
+	DIR *dir = opendir(path);
+	size_t n = strlen(name);
+	bool result = false;
+
+	if (dir) {
+		while (d && !result) {
+			d = readdir(dir);
+			result = d ? strncmp(d->d_name, name, n) : false;
+		}
+		closedir(dir);
+	}
+
+	return result;
+}
+
+char *perf_data__kallsyms_name(struct perf_data *data)
+{
+	char *kallsyms_name;
+	struct stat st;
+
+	if (!data->is_dir)
+		return NULL;
+
+	if (asprintf(&kallsyms_name, "%s/kcore_dir/kallsyms", data->path) < 0)
+		return NULL;
+
+	if (stat(kallsyms_name, &st)) {
+		free(kallsyms_name);
+		return NULL;
+	}
+
+	return kallsyms_name;
+}
+
+char *perf_data__guest_kallsyms_name(struct perf_data *data, pid_t machine_pid)
+{
+	char *kallsyms_name;
+	struct stat st;
+
+	if (!data->is_dir)
+		return NULL;
+
+	if (asprintf(&kallsyms_name, "%s/kcore_dir__%d/kallsyms", data->path, machine_pid) < 0)
+		return NULL;
+
+	if (stat(kallsyms_name, &st)) {
+		free(kallsyms_name);
+		return NULL;
+	}
+
+	return kallsyms_name;
+}
+
+bool is_perf_data(const char *path)
+{
+	bool ret = false;
+	FILE *file;
+	u64 magic;
+
+	file = fopen(path, "r");
+	if (!file)
+		return false;
+
+	if (fread(&magic, 1, 8, file) < 8)
+		goto out;
+
+	ret = is_perf_magic(magic);
+out:
+	fclose(file);
+	return ret;
+}