243 lines
6.2 KiB
C
243 lines
6.2 KiB
C
/*
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* builtin-probe.c
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*
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* Builtin probe command: Set up probe events by C expression
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*
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* Written by Masami Hiramatsu <mhiramat@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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*/
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#define _GNU_SOURCE
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#include <sys/utsname.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#undef _GNU_SOURCE
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#include "perf.h"
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#include "builtin.h"
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#include "util/util.h"
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#include "util/event.h"
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#include "util/debug.h"
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#include "util/parse-options.h"
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#include "util/parse-events.h" /* For debugfs_path */
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#include "util/probe-finder.h"
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#include "util/probe-event.h"
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/* Default vmlinux search paths */
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#define NR_SEARCH_PATH 3
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const char *default_search_path[NR_SEARCH_PATH] = {
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"/lib/modules/%s/build/vmlinux", /* Custom build kernel */
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"/usr/lib/debug/lib/modules/%s/vmlinux", /* Red Hat debuginfo */
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"/boot/vmlinux-debug-%s", /* Ubuntu */
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};
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#define MAX_PATH_LEN 256
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#define MAX_PROBES 128
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/* Session management structure */
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static struct {
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char *vmlinux;
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char *release;
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int need_dwarf;
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int nr_probe;
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struct probe_point probes[MAX_PROBES];
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} session;
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static bool listing;
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/* Parse an event definition. Note that any error must die. */
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static void parse_probe_event(const char *str)
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{
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struct probe_point *pp = &session.probes[session.nr_probe];
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pr_debug("probe-definition(%d): %s\n", session.nr_probe, str);
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if (++session.nr_probe == MAX_PROBES)
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die("Too many probes (> %d) are specified.", MAX_PROBES);
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/* Parse perf-probe event into probe_point */
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session.need_dwarf = parse_perf_probe_event(str, pp);
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pr_debug("%d arguments\n", pp->nr_args);
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}
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static int opt_add_probe_event(const struct option *opt __used,
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const char *str, int unset __used)
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{
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if (str)
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parse_probe_event(str);
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return 0;
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}
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#ifndef NO_LIBDWARF
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static int open_default_vmlinux(void)
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{
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struct utsname uts;
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char fname[MAX_PATH_LEN];
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int fd, ret, i;
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ret = uname(&uts);
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if (ret) {
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pr_debug("uname() failed.\n");
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return -errno;
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}
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session.release = uts.release;
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for (i = 0; i < NR_SEARCH_PATH; i++) {
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ret = snprintf(fname, MAX_PATH_LEN,
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default_search_path[i], session.release);
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if (ret >= MAX_PATH_LEN || ret < 0) {
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pr_debug("Filename(%d,%s) is too long.\n", i,
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uts.release);
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errno = E2BIG;
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return -E2BIG;
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}
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pr_debug("try to open %s\n", fname);
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fd = open(fname, O_RDONLY);
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if (fd >= 0)
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break;
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}
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return fd;
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}
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#endif
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static const char * const probe_usage[] = {
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"perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]",
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"perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
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"perf probe --list",
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NULL
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};
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static const struct option options[] = {
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OPT_BOOLEAN('v', "verbose", &verbose,
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"be more verbose (show parsed arguments, etc)"),
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#ifndef NO_LIBDWARF
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OPT_STRING('k', "vmlinux", &session.vmlinux, "file",
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"vmlinux/module pathname"),
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#endif
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OPT_BOOLEAN('l', "list", &listing, "list up current probes"),
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OPT_CALLBACK('a', "add", NULL,
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#ifdef NO_LIBDWARF
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"FUNC[+OFFS|%return] [ARG ...]",
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#else
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"FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [ARG ...]",
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#endif
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"probe point definition, where\n"
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"\t\tGRP:\tGroup name (optional)\n"
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"\t\tNAME:\tEvent name\n"
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"\t\tFUNC:\tFunction name\n"
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"\t\tOFFS:\tOffset from function entry (in byte)\n"
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"\t\t%return:\tPut the probe at function return\n"
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#ifdef NO_LIBDWARF
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"\t\tARG:\tProbe argument (only \n"
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#else
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"\t\tSRC:\tSource code path\n"
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"\t\tRLN:\tRelative line number from function entry.\n"
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"\t\tALN:\tAbsolute line number in file.\n"
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"\t\tARG:\tProbe argument (local variable name or\n"
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#endif
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"\t\t\tkprobe-tracer argument format.)\n",
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opt_add_probe_event),
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OPT_END()
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};
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int cmd_probe(int argc, const char **argv, const char *prefix __used)
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{
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int i, j, ret;
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#ifndef NO_LIBDWARF
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int fd;
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#endif
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struct probe_point *pp;
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argc = parse_options(argc, argv, options, probe_usage,
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PARSE_OPT_STOP_AT_NON_OPTION);
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for (i = 0; i < argc; i++)
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parse_probe_event(argv[i]);
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if ((session.nr_probe == 0 && !listing) ||
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(session.nr_probe != 0 && listing))
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usage_with_options(probe_usage, options);
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if (listing) {
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show_perf_probe_events();
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return 0;
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}
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if (session.need_dwarf)
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#ifdef NO_LIBDWARF
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die("Debuginfo-analysis is not supported");
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#else /* !NO_LIBDWARF */
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pr_debug("Some probes require debuginfo.\n");
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if (session.vmlinux)
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fd = open(session.vmlinux, O_RDONLY);
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else
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fd = open_default_vmlinux();
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if (fd < 0) {
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if (session.need_dwarf)
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die("Could not open vmlinux/module file.");
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pr_debug("Could not open vmlinux/module file."
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" Try to use symbols.\n");
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goto end_dwarf;
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}
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/* Searching probe points */
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for (j = 0; j < session.nr_probe; j++) {
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pp = &session.probes[j];
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if (pp->found)
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continue;
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lseek(fd, SEEK_SET, 0);
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ret = find_probepoint(fd, pp);
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if (ret < 0) {
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if (session.need_dwarf)
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die("Could not analyze debuginfo.");
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pr_warning("An error occurred in debuginfo analysis. Try to use symbols.\n");
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break;
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}
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if (ret == 0) /* No error but failed to find probe point. */
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die("No probe point found.");
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}
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close(fd);
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end_dwarf:
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#endif /* !NO_LIBDWARF */
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/* Synthesize probes without dwarf */
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for (j = 0; j < session.nr_probe; j++) {
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pp = &session.probes[j];
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if (pp->found) /* This probe is already found. */
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continue;
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ret = synthesize_trace_kprobe_event(pp);
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if (ret == -E2BIG)
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die("probe point definition becomes too long.");
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else if (ret < 0)
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die("Failed to synthesize a probe point.");
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}
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/* Settng up probe points */
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add_trace_kprobe_events(session.probes, session.nr_probe);
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return 0;
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}
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