From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace 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 --- tools/perf/tests/switch-tracking.c | 598 +++++++++++++++++++++++++++++++++++++ 1 file changed, 598 insertions(+) create mode 100644 tools/perf/tests/switch-tracking.c (limited to 'tools/perf/tests/switch-tracking.c') diff --git a/tools/perf/tests/switch-tracking.c b/tools/perf/tests/switch-tracking.c new file mode 100644 index 000000000..73568c782 --- /dev/null +++ b/tools/perf/tests/switch-tracking.c @@ -0,0 +1,598 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "debug.h" +#include "parse-events.h" +#include "evlist.h" +#include "evsel.h" +#include "thread_map.h" +#include "record.h" +#include "tests.h" +#include "util/mmap.h" +#include "util/sample.h" +#include "pmus.h" + +static int spin_sleep(void) +{ + struct timeval start, now, diff, maxtime; + struct timespec ts; + int err, i; + + maxtime.tv_sec = 0; + maxtime.tv_usec = 50000; + + err = gettimeofday(&start, NULL); + if (err) + return err; + + /* Spin for 50ms */ + while (1) { + for (i = 0; i < 1000; i++) + barrier(); + + err = gettimeofday(&now, NULL); + if (err) + return err; + + timersub(&now, &start, &diff); + if (timercmp(&diff, &maxtime, > /* For checkpatch */)) + break; + } + + ts.tv_nsec = 50 * 1000 * 1000; + ts.tv_sec = 0; + + /* Sleep for 50ms */ + err = nanosleep(&ts, NULL); + if (err == EINTR) + err = 0; + + return err; +} + +struct switch_tracking { + struct evsel *switch_evsel; + struct evsel *cycles_evsel; + pid_t *tids; + int nr_tids; + int comm_seen[4]; + int cycles_before_comm_1; + int cycles_between_comm_2_and_comm_3; + int cycles_after_comm_4; +}; + +static int check_comm(struct switch_tracking *switch_tracking, + union perf_event *event, const char *comm, int nr) +{ + if (event->header.type == PERF_RECORD_COMM && + (pid_t)event->comm.pid == getpid() && + (pid_t)event->comm.tid == getpid() && + strcmp(event->comm.comm, comm) == 0) { + if (switch_tracking->comm_seen[nr]) { + pr_debug("Duplicate comm event\n"); + return -1; + } + switch_tracking->comm_seen[nr] = 1; + pr_debug3("comm event: %s nr: %d\n", event->comm.comm, nr); + return 1; + } + return 0; +} + +static int check_cpu(struct switch_tracking *switch_tracking, int cpu) +{ + int i, nr = cpu + 1; + + if (cpu < 0) + return -1; + + if (!switch_tracking->tids) { + switch_tracking->tids = calloc(nr, sizeof(pid_t)); + if (!switch_tracking->tids) + return -1; + for (i = 0; i < nr; i++) + switch_tracking->tids[i] = -1; + switch_tracking->nr_tids = nr; + return 0; + } + + if (cpu >= switch_tracking->nr_tids) { + void *addr; + + addr = realloc(switch_tracking->tids, nr * sizeof(pid_t)); + if (!addr) + return -1; + switch_tracking->tids = addr; + for (i = switch_tracking->nr_tids; i < nr; i++) + switch_tracking->tids[i] = -1; + switch_tracking->nr_tids = nr; + return 0; + } + + return 0; +} + +static int process_sample_event(struct evlist *evlist, + union perf_event *event, + struct switch_tracking *switch_tracking) +{ + struct perf_sample sample; + struct evsel *evsel; + pid_t next_tid, prev_tid; + int cpu, err; + + perf_sample__init(&sample, /*all=*/false); + if (evlist__parse_sample(evlist, event, &sample)) { + pr_debug("evlist__parse_sample failed\n"); + err = -1; + goto out; + } + + evsel = sample.evsel; + if (!evsel) + evsel = evlist__id2evsel(evlist, sample.id); + + if (evsel == switch_tracking->switch_evsel) { + next_tid = perf_sample__intval(&sample, "next_pid"); + prev_tid = perf_sample__intval(&sample, "prev_pid"); + cpu = sample.cpu; + pr_debug3("sched_switch: cpu: %d prev_tid %d next_tid %d\n", + cpu, prev_tid, next_tid); + err = check_cpu(switch_tracking, cpu); + if (err) + goto out; + /* + * Check for no missing sched_switch events i.e. that the + * evsel->core.system_wide flag has worked. + */ + if (switch_tracking->tids[cpu] != -1 && + switch_tracking->tids[cpu] != prev_tid) { + pr_debug("Missing sched_switch events\n"); + err = -1; + goto out; + } + switch_tracking->tids[cpu] = next_tid; + } + + if (evsel == switch_tracking->cycles_evsel) { + pr_debug3("cycles event\n"); + if (!switch_tracking->comm_seen[0]) + switch_tracking->cycles_before_comm_1 = 1; + if (switch_tracking->comm_seen[1] && + !switch_tracking->comm_seen[2]) + switch_tracking->cycles_between_comm_2_and_comm_3 = 1; + if (switch_tracking->comm_seen[3]) + switch_tracking->cycles_after_comm_4 = 1; + } + + err = 0; +out: + perf_sample__exit(&sample); + return err; +} + +static int process_event(struct evlist *evlist, union perf_event *event, + struct switch_tracking *switch_tracking) +{ + if (event->header.type == PERF_RECORD_SAMPLE) + return process_sample_event(evlist, event, switch_tracking); + + if (event->header.type == PERF_RECORD_COMM) { + int err, done = 0; + + err = check_comm(switch_tracking, event, "Test COMM 1", 0); + if (err < 0) + return -1; + done += err; + err = check_comm(switch_tracking, event, "Test COMM 2", 1); + if (err < 0) + return -1; + done += err; + err = check_comm(switch_tracking, event, "Test COMM 3", 2); + if (err < 0) + return -1; + done += err; + err = check_comm(switch_tracking, event, "Test COMM 4", 3); + if (err < 0) + return -1; + done += err; + if (done != 1) { + pr_debug("Unexpected comm event\n"); + return -1; + } + } + + return 0; +} + +struct event_node { + struct list_head list; + union perf_event *event; + u64 event_time; +}; + +static int add_event(struct evlist *evlist, struct list_head *events, + union perf_event *event) +{ + struct perf_sample sample; + struct event_node *node; + + node = malloc(sizeof(struct event_node)); + if (!node) { + pr_debug("malloc failed\n"); + return -1; + } + node->event = event; + list_add(&node->list, events); + + if (evlist__parse_sample(evlist, event, &sample)) { + pr_debug("evlist__parse_sample failed\n"); + perf_sample__exit(&sample); + return -1; + } + + if (!sample.time) { + pr_debug("event with no time\n"); + perf_sample__exit(&sample); + return -1; + } + + node->event_time = sample.time; + + perf_sample__exit(&sample); + return 0; +} + +static void free_event_nodes(struct list_head *events) +{ + struct event_node *node; + + while (!list_empty(events)) { + node = list_entry(events->next, struct event_node, list); + list_del_init(&node->list); + free(node); + } +} + +static int compar(const void *a, const void *b) +{ + const struct event_node *nodea = a; + const struct event_node *nodeb = b; + s64 cmp = nodea->event_time - nodeb->event_time; + + return cmp < 0 ? -1 : (cmp > 0 ? 1 : 0); +} + +static int process_events(struct evlist *evlist, + struct switch_tracking *switch_tracking) +{ + union perf_event *event; + unsigned pos, cnt = 0; + LIST_HEAD(events); + struct event_node *events_array, *node; + struct mmap *md; + int i, ret; + + for (i = 0; i < evlist__core(evlist)->nr_mmaps; i++) { + md = &evlist__mmap(evlist)[i]; + if (perf_mmap__read_init(&md->core) < 0) + continue; + + while ((event = perf_mmap__read_event(&md->core)) != NULL) { + cnt += 1; + ret = add_event(evlist, &events, event); + perf_mmap__consume(&md->core); + if (ret < 0) + goto out_free_nodes; + } + perf_mmap__read_done(&md->core); + } + + events_array = calloc(cnt, sizeof(struct event_node)); + if (!events_array) { + pr_debug("calloc failed\n"); + ret = -1; + goto out_free_nodes; + } + + pos = 0; + list_for_each_entry(node, &events, list) + events_array[pos++] = *node; + + qsort(events_array, cnt, sizeof(struct event_node), compar); + + for (pos = 0; pos < cnt; pos++) { + ret = process_event(evlist, events_array[pos].event, + switch_tracking); + if (ret < 0) + goto out_free; + } + + ret = 0; +out_free: + pr_debug("%u events recorded\n", cnt); + free(events_array); +out_free_nodes: + free_event_nodes(&events); + return ret; +} + +/** + * test__switch_tracking - test using sched_switch and tracking events. + * + * This function implements a test that checks that sched_switch events and + * tracking events can be recorded for a workload (current process) using the + * evsel->core.system_wide and evsel->tracking flags (respectively) with other events + * sometimes enabled or disabled. + */ +static int test__switch_tracking(struct test_suite *test __maybe_unused, int subtest __maybe_unused) +{ + const char *sched_switch = "sched:sched_switch"; + const char *cycles = "cpu-cycles:u"; + struct switch_tracking switch_tracking = { .tids = NULL, }; + struct record_opts opts = { + .mmap_pages = UINT_MAX, + .user_freq = UINT_MAX, + .user_interval = ULLONG_MAX, + .freq = 4000, + .target = { + .uses_mmap = true, + }, + }; + struct perf_thread_map *threads = NULL; + struct perf_cpu_map *cpus = NULL; + struct evlist *evlist = NULL; + struct evsel *evsel, *cpu_clocks_evsel, *cycles_evsel; + struct evsel *switch_evsel, *tracking_evsel; + const char *comm; + int err = -1; + + threads = thread_map__new_by_tid(getpid()); + if (!threads) { + pr_debug("thread_map__new failed!\n"); + goto out_err; + } + + cpus = perf_cpu_map__new_online_cpus(); + if (!cpus) { + pr_debug("perf_cpu_map__new failed!\n"); + goto out_err; + } + + evlist = evlist__new(); + if (!evlist) { + pr_debug("evlist__new failed!\n"); + goto out_err; + } + + perf_evlist__set_maps(evlist__core(evlist), cpus, threads); + + /* First event */ + err = parse_event(evlist, "cpu-clock:u"); + if (err) { + pr_debug("Failed to parse event dummy:u\n"); + goto out_err; + } + + cpu_clocks_evsel = evlist__last(evlist); + + /* Second event */ + err = parse_event(evlist, cycles); + if (err) { + pr_debug("Failed to parse event %s\n", cycles); + goto out_err; + } + + cycles_evsel = evlist__last(evlist); + + /* Third event */ + if (!evlist__can_select_event(evlist, sched_switch)) { + pr_debug("No sched_switch\n"); + err = 0; + goto out; + } + + switch_evsel = evlist__add_sched_switch(evlist, true); + if (IS_ERR(switch_evsel)) { + err = PTR_ERR(switch_evsel); + pr_debug("Failed to create event %s\n", sched_switch); + goto out_err; + } + + switch_evsel->immediate = true; + + /* Test moving an event to the front */ + if (cycles_evsel == evlist__first(evlist)) { + pr_debug("cycles event already at front"); + goto out_err; + } + evlist__to_front(evlist, cycles_evsel); + if (cycles_evsel != evlist__first(evlist)) { + pr_debug("Failed to move cycles event to front"); + goto out_err; + } + + evsel__set_sample_bit(cycles_evsel, CPU); + evsel__set_sample_bit(cycles_evsel, TIME); + + /* Fourth event */ + err = parse_event(evlist, "dummy:u"); + if (err) { + pr_debug("Failed to parse event dummy:u\n"); + goto out_err; + } + + tracking_evsel = evlist__last(evlist); + + evlist__set_tracking_event(evlist, tracking_evsel); + + tracking_evsel->core.attr.freq = 0; + tracking_evsel->core.attr.sample_period = 1; + + evsel__set_sample_bit(tracking_evsel, TIME); + + /* Config events */ + evlist__config(evlist, &opts, NULL); + + /* Check moved event is still at the front */ + if (cycles_evsel != evlist__first(evlist)) { + pr_debug("Front event no longer at front"); + goto out_err; + } + + /* Check tracking event is tracking */ + if (!tracking_evsel->core.attr.mmap || !tracking_evsel->core.attr.comm) { + pr_debug("Tracking event not tracking\n"); + goto out_err; + } + + /* Check non-tracking events are not tracking */ + evlist__for_each_entry(evlist, evsel) { + if (evsel != tracking_evsel) { + if (evsel->core.attr.mmap || evsel->core.attr.comm) { + pr_debug("Non-tracking event is tracking\n"); + goto out_err; + } + } + } + + if (evlist__open(evlist) < 0) { + pr_debug("Not supported\n"); + err = 0; + goto out; + } + + err = evlist__do_mmap(evlist, UINT_MAX); + if (err) { + pr_debug("evlist__mmap failed!\n"); + goto out_err; + } + + evlist__enable(evlist); + + err = evsel__disable(cpu_clocks_evsel); + if (err) { + pr_debug("perf_evlist__disable_event failed!\n"); + goto out_err; + } + + err = spin_sleep(); + if (err) { + pr_debug("spin_sleep failed!\n"); + goto out_err; + } + + comm = "Test COMM 1"; + err = prctl(PR_SET_NAME, (unsigned long)comm, 0, 0, 0); + if (err) { + pr_debug("PR_SET_NAME failed!\n"); + goto out_err; + } + + err = evsel__disable(cycles_evsel); + if (err) { + pr_debug("perf_evlist__disable_event failed!\n"); + goto out_err; + } + + comm = "Test COMM 2"; + err = prctl(PR_SET_NAME, (unsigned long)comm, 0, 0, 0); + if (err) { + pr_debug("PR_SET_NAME failed!\n"); + goto out_err; + } + + err = spin_sleep(); + if (err) { + pr_debug("spin_sleep failed!\n"); + goto out_err; + } + + comm = "Test COMM 3"; + err = prctl(PR_SET_NAME, (unsigned long)comm, 0, 0, 0); + if (err) { + pr_debug("PR_SET_NAME failed!\n"); + goto out_err; + } + + err = evsel__enable(cycles_evsel); + if (err) { + pr_debug("perf_evlist__disable_event failed!\n"); + goto out_err; + } + + comm = "Test COMM 4"; + err = prctl(PR_SET_NAME, (unsigned long)comm, 0, 0, 0); + if (err) { + pr_debug("PR_SET_NAME failed!\n"); + goto out_err; + } + + err = spin_sleep(); + if (err) { + pr_debug("spin_sleep failed!\n"); + goto out_err; + } + + evlist__disable(evlist); + + switch_tracking.switch_evsel = switch_evsel; + switch_tracking.cycles_evsel = cycles_evsel; + + err = process_events(evlist, &switch_tracking); + + zfree(&switch_tracking.tids); + + if (err) + goto out_err; + + /* Check all 4 comm events were seen i.e. that evsel->tracking works */ + if (!switch_tracking.comm_seen[0] || !switch_tracking.comm_seen[1] || + !switch_tracking.comm_seen[2] || !switch_tracking.comm_seen[3]) { + pr_debug("Missing comm events\n"); + goto out_err; + } + + /* Check cycles event got enabled */ + if (!switch_tracking.cycles_before_comm_1) { + pr_debug("Missing cycles events\n"); + goto out_err; + } + + /* Check cycles event got disabled */ + if (switch_tracking.cycles_between_comm_2_and_comm_3) { + pr_debug("cycles events even though event was disabled\n"); + goto out_err; + } + + /* Check cycles event got enabled again */ + if (!switch_tracking.cycles_after_comm_4) { + pr_debug("Missing cycles events\n"); + goto out_err; + } +out: + if (evlist) { + evlist__disable(evlist); + evlist__put(evlist); + } + perf_cpu_map__put(cpus); + perf_thread_map__put(threads); + + return err; + +out_err: + err = -1; + goto out; +} + +DEFINE_SUITE_EXCLUSIVE("Track with sched_switch", switch_tracking); -- cgit v1.3.1