tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
perf test: Add kallsyms split test
Create a fake root directory for /proc/{version,modules,kallsyms} in
/tmp for testing. The kallsyms has a bad symbol in the module and it
causes the main map splitted. The test ensures it only has two maps -
kernel and the module and it finds the initial map after the module
without creating the split maps like [kernel].0 and so on.
$ perf test -vv "split kallsyms"
69: split kallsyms:
--- start ---
test child forked, pid 1016196
try to create fake root directory
create kernel maps from the fake root directory
maps__set_modules_path_dir: cannot open /tmp/perf-test.Zrv6Sy/lib/modules/X.Y.Z dir
Problems setting modules path maps, continuing anyway...
Failed to open /tmp/perf-test.Zrv6Sy/proc/kcore. Note /proc/kcore requires CAP_SYS_RAWIO capability to access.
Using /tmp/perf-test.Zrv6Sy/proc/kallsyms for symbols
kernel map loaded - check symbol and map
---- end(0) ----
69: split kallsyms : Ok
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
+159
+1
tools/perf/tests/Build
+1
tools/perf/tests/Build
+1
tools/perf/tests/builtin-test.c
+1
tools/perf/tests/builtin-test.c
+156
tools/perf/tests/kallsyms-split.c
+156
tools/perf/tests/kallsyms-split.c
···
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/compiler.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include "util/dso.h"
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#include "util/map.h"
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#include "util/symbol.h"
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#include "util/debug.h"
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#include "util/machine.h"
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#include "tests.h"
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/*
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* This test is to check whether a bad symbol in a module won't split kallsyms maps.
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* The main_symbol[1-3] should belong to the main [kernel.kallsyms] map even if the
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* bad_symbol from the module is found in the middle.
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*/
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static char root_template[] = "/tmp/perf-test.XXXXXX";
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static char *root_dir;
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static const char proc_version[] = "Linux version X.Y.Z (just for perf test)\n";
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static const char proc_modules[] = "module 4096 1 - Live 0xffffffffcd000000\n";
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static const char proc_kallsyms[] =
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"ffffffffab200000 T _stext\n"
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"ffffffffab200010 T good_symbol\n"
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"ffffffffab200020 t bad_symbol\n"
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"ffffffffab200030 t main_symbol1\n"
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"ffffffffab200040 t main_symbol2\n"
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"ffffffffab200050 t main_symbol3\n"
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"ffffffffab200060 T _etext\n"
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"ffffffffcd000000 T start_module\t[module]\n"
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"ffffffffab200020 u bad_symbol\t[module]\n"
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"ffffffffcd000040 T end_module\t[module]\n";
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static struct {
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const char *name;
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const char *contents;
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long len;
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} proc_files[] = {
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{ "version", proc_version, sizeof(proc_version) - 1 },
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{ "modules", proc_modules, sizeof(proc_modules) - 1 },
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{ "kallsyms", proc_kallsyms, sizeof(proc_kallsyms) - 1 },
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};
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static void remove_proc_dir(int sig __maybe_unused)
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{
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char buf[128];
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if (root_dir == NULL)
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return;
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for (unsigned i = 0; i < ARRAY_SIZE(proc_files); i++) {
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scnprintf(buf, sizeof(buf), "%s/proc/%s", root_dir, proc_files[i].name);
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remove(buf);
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}
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scnprintf(buf, sizeof(buf), "%s/proc", root_dir);
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rmdir(buf);
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rmdir(root_dir);
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root_dir = NULL;
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}
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static int create_proc_dir(void)
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{
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char buf[128];
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root_dir = mkdtemp(root_template);
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if (root_dir == NULL)
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return -1;
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scnprintf(buf, sizeof(buf), "%s/proc", root_dir);
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if (mkdir(buf, 0700) < 0)
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goto err;
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for (unsigned i = 0; i < ARRAY_SIZE(proc_files); i++) {
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int fd, len;
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scnprintf(buf, sizeof(buf), "%s/proc/%s", root_dir, proc_files[i].name);
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fd = open(buf, O_RDWR | O_CREAT, 0600);
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if (fd < 0)
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goto err;
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len = write(fd, proc_files[i].contents, proc_files[i].len);
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close(fd);
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if (len != proc_files[i].len)
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goto err;
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}
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return 0;
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err:
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remove_proc_dir(0);
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return -1;
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}
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static int test__kallsyms_split(struct test_suite *test __maybe_unused,
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int subtest __maybe_unused)
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{
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struct machine m;
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struct map *map = NULL;
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int ret = TEST_FAIL;
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pr_debug("try to create fake root directory\n");
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if (create_proc_dir() < 0) {
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pr_debug("SKIP: cannot create a fake root directory\n");
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return TEST_SKIP;
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}
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signal(SIGINT, remove_proc_dir);
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signal(SIGPIPE, remove_proc_dir);
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signal(SIGSEGV, remove_proc_dir);
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signal(SIGTERM, remove_proc_dir);
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pr_debug("create kernel maps from the fake root directory\n");
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machine__init(&m, root_dir, HOST_KERNEL_ID);
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if (machine__create_kernel_maps(&m) < 0) {
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pr_debug("FAIL: failed to create kernel maps\n");
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goto out;
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}
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/* force to use /proc/kallsyms */
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symbol_conf.ignore_vmlinux = true;
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symbol_conf.ignore_vmlinux_buildid = true;
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symbol_conf.allow_aliases = true;
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if (map__load(machine__kernel_map(&m)) < 0) {
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pr_debug("FAIL: failed to load kallsyms\n");
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goto out;
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}
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pr_debug("kernel map loaded - check symbol and map\n");
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if (maps__nr_maps(machine__kernel_maps(&m)) != 2) {
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pr_debug("FAIL: it should have the kernel and a module, but has %u maps\n",
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maps__nr_maps(machine__kernel_maps(&m)));
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goto out;
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}
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if (machine__find_kernel_symbol_by_name(&m, "main_symbol3", &map) == NULL) {
140
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pr_debug("FAIL: failed to find a symbol\n");
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goto out;
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}
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if (!RC_CHK_EQUAL(map, machine__kernel_map(&m))) {
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pr_debug("FAIL: the symbol is not in the kernel map\n");
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goto out;
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}
148
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ret = TEST_OK;
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150
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out:
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remove_proc_dir(0);
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machine__exit(&m);
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return ret;
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}
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DEFINE_SUITE("split kallsyms", kallsyms_split);