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, 436 insertions, 0 deletions

diff --git a/tools/perf/util/addr2line.c b/tools/perf/util/addr2line.c
new file mode 100644
index 000000000..4b0d349ed
--- /dev/null
+++ b/tools/perf/util/addr2line.c
@@ -0,0 +1,436 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "addr2line.h"
+#include "debug.h"
+#include "dso.h"
+#include "string2.h"
+#include "srcline.h"
+#include "symbol.h"
+#include "symbol_conf.h"
+
+#include <api/io.h>
+#include <linux/zalloc.h>
+#include <subcmd/run-command.h>
+
+#include <inttypes.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define MAX_INLINE_NEST 1024
+
+static int filename_split(char *filename, unsigned int *line_nr)
+{
+	char *sep;
+
+	sep = strchr(filename, '\n');
+	if (sep)
+		*sep = '\0';
+
+	if (!strcmp(filename, "??:0"))
+		return 0;
+
+	sep = strchr(filename, ':');
+	if (sep) {
+		*sep++ = '\0';
+		*line_nr = strtoul(sep, NULL, 0);
+		return 1;
+	}
+	pr_debug("addr2line missing ':' in filename split\n");
+	return 0;
+}
+
+static void addr2line_subprocess_cleanup(struct child_process *a2l)
+{
+	if (a2l->pid != -1) {
+		kill(a2l->pid, SIGKILL);
+		finish_command(a2l); /* ignore result, we don't care */
+		a2l->pid = -1;
+		close(a2l->in);
+		close(a2l->out);
+	}
+
+	free(a2l);
+}
+
+static struct child_process *addr2line_subprocess_init(const char *addr2line_path,
+							const char *binary_path)
+{
+	const char *argv[] = {
+		addr2line_path ?: "addr2line",
+		"-e", binary_path,
+		"-a", "-i", "-f", NULL
+	};
+	struct child_process *a2l = zalloc(sizeof(*a2l));
+	int start_command_status = 0;
+
+	if (a2l == NULL) {
+		pr_err("Failed to allocate memory for addr2line");
+		return NULL;
+	}
+
+	a2l->pid = -1;
+	a2l->in = -1;
+	a2l->out = -1;
+	a2l->no_stderr = 1;
+
+	a2l->argv = argv;
+	start_command_status = start_command(a2l);
+	a2l->argv = NULL; /* it's not used after start_command; avoid dangling pointers */
+
+	if (start_command_status != 0) {
+		pr_warning("could not start addr2line (%s) for %s: start_command return code %d\n",
+			addr2line_path, binary_path, start_command_status);
+		addr2line_subprocess_cleanup(a2l);
+		return NULL;
+	}
+
+	return a2l;
+}
+
+enum cmd_a2l_style {
+	BROKEN,
+	GNU_BINUTILS,
+	LLVM,
+};
+
+static enum cmd_a2l_style cmd_addr2line_configure(struct child_process *a2l, const char *dso_name)
+{
+	static bool cached;
+	static enum cmd_a2l_style style;
+
+	if (!cached) {
+		char buf[128];
+		struct io io;
+		int ch;
+		int lines;
+
+		if (write(a2l->in, ",\n", 2) != 2)
+			return BROKEN;
+
+		io__init(&io, a2l->out, buf, sizeof(buf));
+		ch = io__get_char(&io);
+		if (ch == ',') {
+			style = LLVM;
+			cached = true;
+			lines = 1;
+			pr_debug3("Detected LLVM addr2line style\n");
+		} else if (ch == '0') {
+			style = GNU_BINUTILS;
+			cached = true;
+			lines = 3;
+			pr_debug3("Detected binutils addr2line style\n");
+		} else {
+			if (!symbol_conf.addr2line_disable_warn) {
+				char *output = NULL;
+				size_t output_len;
+
+				io__getline(&io, &output, &output_len);
+				pr_warning("%s %s: addr2line configuration failed\n",
+					   __func__, dso_name);
+				pr_warning("\t%c%s", ch, output);
+			}
+			pr_debug("Unknown/broken addr2line style\n");
+			return BROKEN;
+		}
+		while (lines) {
+			ch = io__get_char(&io);
+			if (ch <= 0)
+				break;
+			if (ch == '\n')
+				lines--;
+		}
+		/* Ignore SIGPIPE in the event addr2line exits. */
+		signal(SIGPIPE, SIG_IGN);
+	}
+	return style;
+}
+
+static int read_addr2line_record(struct io *io,
+				 enum cmd_a2l_style style,
+				 const char *dso_name,
+				 u64 addr,
+				 bool first,
+				 char **function,
+				 char **filename,
+				 unsigned int *line_nr)
+{
+	/*
+	 * Returns:
+	 * -1 ==> error
+	 * 0 ==> sentinel (or other ill-formed) record read
+	 * 1 ==> a genuine record read
+	 */
+	char *line = NULL;
+	size_t line_len = 0;
+	unsigned int dummy_line_nr = 0;
+	int ret = -1;
+
+	if (function != NULL)
+		zfree(function);
+
+	if (filename != NULL)
+		zfree(filename);
+
+	if (line_nr != NULL)
+		*line_nr = 0;
+
+	/*
+	 * Read the first line. Without an error this will be:
+	 * - for the first line an address like 0x1234,
+	 * - the binutils sentinel 0x0000000000000000,
+	 * - the llvm-addr2line the sentinel ',' character,
+	 * - the function name line for an inlined function.
+	 */
+	if (io__getline(io, &line, &line_len) < 0 || !line_len)
+		goto error;
+
+	pr_debug3("%s %s: addr2line read address for sentinel: %s", __func__, dso_name, line);
+	if (style == LLVM && line_len == 2 && line[0] == ',') {
+		/* Found the llvm-addr2line sentinel character. */
+		zfree(&line);
+		return 0;
+	} else if (style == GNU_BINUTILS && (!first || addr != 0)) {
+		int zero_count = 0, non_zero_count = 0;
+		/*
+		 * Check for binutils sentinel ignoring it for the case the
+		 * requested address is 0.
+		 */
+
+		/* A given address should always start 0x. */
+		if (line_len >= 2 || line[0] != '0' || line[1] != 'x') {
+			for (size_t i = 2; i < line_len; i++) {
+				if (line[i] == '0')
+					zero_count++;
+				else if (line[i] != '\n')
+					non_zero_count++;
+			}
+			if (!non_zero_count) {
+				int ch;
+
+				if (first && !zero_count) {
+					/* Line was erroneous just '0x'. */
+					goto error;
+				}
+				/*
+				 * Line was 0x0..0, the sentinel for binutils. Remove
+				 * the function and filename lines.
+				 */
+				zfree(&line);
+				do {
+					ch = io__get_char(io);
+				} while (ch > 0 && ch != '\n');
+				do {
+					ch = io__get_char(io);
+				} while (ch > 0 && ch != '\n');
+				return 0;
+			}
+		}
+	}
+	/* Read the second function name line (if inline data then this is the first line). */
+	if (first && (io__getline(io, &line, &line_len) < 0 || !line_len))
+		goto error;
+
+	pr_debug3("%s %s: addr2line read line: %s", __func__, dso_name, line);
+	if (function != NULL)
+		*function = strdup(strim(line));
+
+	zfree(&line);
+	line_len = 0;
+
+	/* Read the third filename and line number line. */
+	if (io__getline(io, &line, &line_len) < 0 || !line_len)
+		goto error;
+
+	pr_debug3("%s %s: addr2line filename:number : %s", __func__, dso_name, line);
+	if (filename_split(line, line_nr == NULL ? &dummy_line_nr : line_nr) == 0 &&
+	    style == GNU_BINUTILS) {
+		ret = 0;
+		goto error;
+	}
+
+	if (filename != NULL)
+		*filename = strdup(line);
+
+	zfree(&line);
+	line_len = 0;
+
+	return 1;
+
+error:
+	free(line);
+	if (function != NULL)
+		zfree(function);
+	if (filename != NULL)
+		zfree(filename);
+	return ret;
+}
+
+static int inline_list__append_record(struct dso *dso,
+				      struct inline_node *node,
+				      struct symbol *sym,
+				      const char *function,
+				      const char *filename,
+				      unsigned int line_nr)
+{
+	struct symbol *inline_sym = new_inline_sym(dso, sym, function);
+
+	return inline_list__append(inline_sym, srcline_from_fileline(filename, line_nr), node);
+}
+
+int cmd__addr2line(const char *dso_name, u64 addr,
+		   char **file, unsigned int *line_nr,
+		   struct dso *dso,
+		   bool unwind_inlines,
+		   struct inline_node *node,
+		   struct symbol *sym __maybe_unused)
+{
+	struct child_process *a2l = dso__a2l(dso);
+	char *record_function = NULL;
+	char *record_filename = NULL;
+	unsigned int record_line_nr = 0;
+	int record_status = -1;
+	int ret = 0;
+	size_t inline_count = 0;
+	int len;
+	char buf[128];
+	ssize_t written;
+	struct io io = { .eof = false };
+	enum cmd_a2l_style cmd_a2l_style;
+
+	if (!a2l) {
+		if (!filename__has_section(dso_name, ".debug_line"))
+			goto out;
+
+		dso__set_a2l(dso,
+			     addr2line_subprocess_init(symbol_conf.addr2line_path, dso_name));
+		a2l = dso__a2l(dso);
+	}
+
+	if (a2l == NULL) {
+		if (!symbol_conf.addr2line_disable_warn)
+			pr_warning("%s %s: addr2line_subprocess_init failed\n", __func__, dso_name);
+		goto out;
+	}
+	cmd_a2l_style = cmd_addr2line_configure(a2l, dso_name);
+	if (cmd_a2l_style == BROKEN)
+		goto out;
+
+	/*
+	 * Send our request and then *deliberately* send something that can't be
+	 * interpreted as a valid address to ask addr2line about (namely,
+	 * ","). This causes addr2line to first write out the answer to our
+	 * request, in an unbounded/unknown number of records, and then to write
+	 * out the lines "0x0...0", "??" and "??:0", for GNU binutils, or ","
+	 * for llvm-addr2line, so that we can detect when it has finished giving
+	 * us anything useful.
+	 */
+	len = snprintf(buf, sizeof(buf), "%016"PRIx64"\n,\n", addr);
+	written = len > 0 ? write(a2l->in, buf, len) : -1;
+	if (written != len) {
+		if (!symbol_conf.addr2line_disable_warn)
+			pr_warning("%s %s: could not send request\n", __func__, dso_name);
+		goto out;
+	}
+	io__init(&io, a2l->out, buf, sizeof(buf));
+	io.timeout_ms = symbol_conf.addr2line_timeout_ms;
+	switch (read_addr2line_record(&io, cmd_a2l_style, dso_name, addr, /*first=*/true,
+				      &record_function, &record_filename, &record_line_nr)) {
+	case -1:
+		if (!symbol_conf.addr2line_disable_warn)
+			pr_warning("%s %s: could not read first record\n", __func__, dso_name);
+		goto out;
+	case 0:
+		/*
+		 * The first record was invalid, so return failure, but first
+		 * read another record, since we sent a sentinel ',' for the
+		 * sake of detected the last inlined function. Treat this as the
+		 * first of a record as the ',' generates a new start with GNU
+		 * binutils, also force a non-zero address as we're no longer
+		 * reading that record.
+		 */
+		switch (read_addr2line_record(&io, cmd_a2l_style, dso_name,
+					      /*addr=*/1, /*first=*/true,
+					      NULL, NULL, NULL)) {
+		case -1:
+			if (!symbol_conf.addr2line_disable_warn)
+				pr_warning("%s %s: could not read sentinel record\n",
+					   __func__, dso_name);
+			break;
+		case 0:
+			/* The sentinel as expected. */
+			break;
+		default:
+			if (!symbol_conf.addr2line_disable_warn)
+				pr_warning("%s %s: unexpected record instead of sentinel",
+					   __func__, dso_name);
+			break;
+		}
+		goto out;
+	default:
+		/* First record as expected. */
+		break;
+	}
+
+	if (file) {
+		*file = strdup(record_filename);
+		ret = 1;
+	}
+	if (line_nr)
+		*line_nr = record_line_nr;
+
+	if (unwind_inlines) {
+		if (node && inline_list__append_record(dso, node, sym,
+						       record_function,
+						       record_filename,
+						       record_line_nr)) {
+			ret = 0;
+			goto out;
+		}
+	}
+
+	/*
+	 * We have to read the records even if we don't care about the inline
+	 * info. This isn't the first record and force the address to non-zero
+	 * as we're reading records beyond the first.
+	 */
+	while ((record_status = read_addr2line_record(&io,
+						      cmd_a2l_style,
+						      dso_name,
+						      /*addr=*/1,
+						      /*first=*/false,
+						      &record_function,
+						      &record_filename,
+						      &record_line_nr)) == 1) {
+		if (unwind_inlines && node && inline_count++ < MAX_INLINE_NEST) {
+			if (inline_list__append_record(dso, node, sym,
+						       record_function,
+						       record_filename,
+						       record_line_nr)) {
+				ret = 0;
+				goto out;
+			}
+			ret = 1; /* found at least one inline frame */
+		}
+	}
+
+out:
+	free(record_function);
+	free(record_filename);
+	if (io.eof) {
+		dso__set_a2l(dso, NULL);
+		addr2line_subprocess_cleanup(a2l);
+	}
+	return ret;
+}
+
+void dso__free_a2l(struct dso *dso)
+{
+	struct child_process *a2l = dso__a2l(dso);
+
+	if (!a2l)
+		return;
+
+	addr2line_subprocess_cleanup(a2l);
+
+	dso__set_a2l(dso, NULL);
+}