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, 451 insertions, 0 deletions

diff --git a/tools/perf/tests/mmap-basic.c b/tools/perf/tests/mmap-basic.c
new file mode 100644
index 000000000..5cec76449
--- /dev/null
+++ b/tools/perf/tests/mmap-basic.c
@@ -0,0 +1,451 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
+#include <inttypes.h>
+#include <stdlib.h>
+
+#include <fcntl.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+
+#include <perf/cpumap.h>
+#include <perf/evlist.h>
+#include <perf/mmap.h>
+
+#include "cpumap.h"
+#include "debug.h"
+#include "event.h"
+#include "evlist.h"
+#include "evsel.h"
+#include "pmu.h"
+#include "pmus.h"
+#include "tests.h"
+#include "thread_map.h"
+#include "util/affinity.h"
+#include "util/mmap.h"
+#include "util/sample.h"
+
+/*
+ * This test will generate random numbers of calls to some getpid syscalls,
+ * then establish an mmap for a group of events that are created to monitor
+ * the syscalls.
+ *
+ * It will receive the events, using mmap, use its PERF_SAMPLE_ID generated
+ * sample.id field to map back to its respective perf_evsel instance.
+ *
+ * Then it checks if the number of syscalls reported as perf events by
+ * the kernel corresponds to the number of syscalls made.
+ */
+static int test__basic_mmap(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
+{
+	int err = TEST_FAIL;
+	union perf_event *event;
+	struct perf_thread_map *threads;
+	struct perf_cpu_map *cpus;
+	struct evlist *evlist;
+	cpu_set_t cpu_set;
+	const char *syscall_names[] = { "getsid", "getppid", "getpgid", };
+	pid_t (*syscalls[])(void) = { (void *)getsid, getppid, (void*)getpgid };
+#define nsyscalls ARRAY_SIZE(syscall_names)
+	unsigned int nr_events[nsyscalls],
+		     expected_nr_events[nsyscalls], i, j;
+	struct evsel *evsels[nsyscalls], *evsel;
+	char sbuf[STRERR_BUFSIZE];
+	struct mmap *md;
+
+	threads = thread_map__new_by_tid(getpid());
+	if (threads == NULL) {
+		pr_debug("thread_map__new\n");
+		return -1;
+	}
+
+	cpus = perf_cpu_map__new_online_cpus();
+	if (cpus == NULL) {
+		pr_debug("perf_cpu_map__new\n");
+		goto out_free_threads;
+	}
+
+	CPU_ZERO(&cpu_set);
+	CPU_SET(perf_cpu_map__cpu(cpus, 0).cpu, &cpu_set);
+	sched_setaffinity(0, sizeof(cpu_set), &cpu_set);
+	if (sched_setaffinity(0, sizeof(cpu_set), &cpu_set) < 0) {
+		pr_debug("sched_setaffinity() failed on CPU %d: %s ",
+			 perf_cpu_map__cpu(cpus, 0).cpu,
+			 str_error_r(errno, sbuf, sizeof(sbuf)));
+		goto out_free_cpus;
+	}
+
+	evlist = evlist__new();
+	if (evlist == NULL) {
+		pr_debug("evlist__new\n");
+		goto out_free_cpus;
+	}
+
+	perf_evlist__set_maps(evlist__core(evlist), cpus, threads);
+
+	for (i = 0; i < nsyscalls; ++i) {
+		char name[64];
+
+		snprintf(name, sizeof(name), "sys_enter_%s", syscall_names[i]);
+		evsels[i] = evsel__newtp("syscalls", name);
+		if (IS_ERR(evsels[i])) {
+			pr_debug("evsel__new(%s)\n", name);
+			if (PTR_ERR(evsels[i]) == -EACCES) {
+				/* Permissions failure, flag the failure as a skip. */
+				err = TEST_SKIP;
+			}
+			goto out_put_evlist;
+		}
+
+		evsels[i]->core.attr.wakeup_events = 1;
+		evsel__set_sample_id(evsels[i], false);
+
+		evlist__add(evlist, evsels[i]);
+
+		if (evsel__open(evsels[i], cpus, threads) < 0) {
+			pr_debug("failed to open counter: %s, "
+				 "tweak /proc/sys/kernel/perf_event_paranoid?\n",
+				 str_error_r(errno, sbuf, sizeof(sbuf)));
+			goto out_put_evlist;
+		}
+
+		nr_events[i] = 0;
+		expected_nr_events[i] = 1 + rand() % 127;
+	}
+
+	if (evlist__do_mmap(evlist, 128) < 0) {
+		pr_debug("failed to mmap events: %d (%s)\n", errno,
+			 str_error_r(errno, sbuf, sizeof(sbuf)));
+		goto out_put_evlist;
+	}
+
+	for (i = 0; i < nsyscalls; ++i)
+		for (j = 0; j < expected_nr_events[i]; ++j) {
+			syscalls[i]();
+		}
+
+	md = &evlist__mmap(evlist)[0];
+	if (perf_mmap__read_init(&md->core) < 0)
+		goto out_init;
+
+	while ((event = perf_mmap__read_event(&md->core)) != NULL) {
+		struct perf_sample sample;
+
+		if (event->header.type != PERF_RECORD_SAMPLE) {
+			pr_debug("unexpected %s event\n",
+				 perf_event__name(event->header.type));
+			goto out_put_evlist;
+		}
+
+		perf_sample__init(&sample, /*all=*/false);
+		err = evlist__parse_sample(evlist, event, &sample);
+		if (err) {
+			pr_err("Can't parse sample, err = %d\n", err);
+			perf_sample__exit(&sample);
+			goto out_put_evlist;
+		}
+
+		err = -1;
+		evsel = sample.evsel;
+		if (!evsel)
+			evsel = evlist__id2evsel(evlist, sample.id);
+		perf_sample__exit(&sample);
+		if (evsel == NULL) {
+			pr_debug("event with id %" PRIu64
+				 " doesn't map to an evsel\n", sample.id);
+			goto out_put_evlist;
+		}
+		nr_events[evsel->core.idx]++;
+		perf_mmap__consume(&md->core);
+	}
+	perf_mmap__read_done(&md->core);
+
+out_init:
+	err = 0;
+	evlist__for_each_entry(evlist, evsel) {
+		if (nr_events[evsel->core.idx] != expected_nr_events[evsel->core.idx]) {
+			pr_debug("expected %d %s events, got %d\n",
+				 expected_nr_events[evsel->core.idx],
+				 evsel__name(evsel), nr_events[evsel->core.idx]);
+			err = -1;
+			goto out_put_evlist;
+		}
+	}
+
+out_put_evlist:
+	evlist__put(evlist);
+out_free_cpus:
+	perf_cpu_map__put(cpus);
+out_free_threads:
+	perf_thread_map__put(threads);
+	return err;
+}
+
+enum user_read_state {
+	USER_READ_ENABLED,
+	USER_READ_DISABLED,
+	USER_READ_UNKNOWN,
+};
+
+static enum user_read_state set_user_read(struct perf_pmu *pmu, enum user_read_state enabled)
+{
+	char buf[2] = {0, '\n'};
+	ssize_t len;
+	int events_fd, rdpmc_fd;
+	enum user_read_state old_user_read = USER_READ_UNKNOWN;
+
+	if (enabled == USER_READ_UNKNOWN)
+		return USER_READ_UNKNOWN;
+
+	events_fd = perf_pmu__event_source_devices_fd();
+	if (events_fd < 0)
+		return USER_READ_UNKNOWN;
+
+	rdpmc_fd = perf_pmu__pathname_fd(events_fd, pmu->name, "rdpmc", O_RDWR);
+	if (rdpmc_fd < 0) {
+		close(events_fd);
+		return USER_READ_UNKNOWN;
+	}
+
+	len = read(rdpmc_fd, buf, sizeof(buf));
+	if (len != sizeof(buf))
+		pr_debug("%s read failed\n", __func__);
+
+	// Note, on Intel hybrid disabling on 1 PMU will implicitly disable on
+	// all the core PMUs.
+	old_user_read = (buf[0] == '1') ? USER_READ_ENABLED : USER_READ_DISABLED;
+
+	if (enabled != old_user_read) {
+		buf[0] = (enabled == USER_READ_ENABLED) ? '1' : '0';
+		len = write(rdpmc_fd, buf, sizeof(buf));
+		if (len != sizeof(buf))
+			pr_debug("%s write failed\n", __func__);
+	}
+	close(rdpmc_fd);
+	close(events_fd);
+	return old_user_read;
+}
+
+static int test_stat_user_read(u64 event, enum user_read_state enabled)
+{
+	struct perf_pmu *pmu = NULL;
+	struct perf_thread_map *threads = perf_thread_map__new_dummy();
+	int ret = TEST_OK;
+
+	pr_err("User space counter reading %" PRIu64 "\n", event);
+	if (!threads) {
+		pr_err("User space counter reading [Failed to create threads]\n");
+		return TEST_FAIL;
+	}
+	perf_thread_map__set_pid(threads, 0, 0);
+
+	while ((pmu = perf_pmus__scan_core(pmu)) != NULL) {
+		enum user_read_state saved_user_read_state = set_user_read(pmu, enabled);
+		struct perf_event_attr attr = {
+			.type	= PERF_TYPE_HARDWARE,
+			.config	= perf_pmus__supports_extended_type()
+			? event | ((u64)pmu->type << PERF_PMU_TYPE_SHIFT)
+				: event,
+#ifdef __aarch64__
+			.config1 = 0x2,		/* Request user access */
+#endif
+		};
+		struct perf_evsel *evsel = NULL;
+		int err;
+		struct perf_event_mmap_page *pc;
+		bool mapped = false, opened = false, rdpmc_supported;
+		struct perf_counts_values counts = { .val = 0 };
+
+
+		pr_debug("User space counter reading for PMU %s\n", pmu->name);
+		/*
+		 * Restrict scheduling to only use the rdpmc on the CPUs the
+		 * event can be on. If the test doesn't run on the CPU of the
+		 * event then the event will be disabled and the pc->index test
+		 * will fail.
+		 */
+		if (pmu->cpus != NULL)
+			cpu_map__set_affinity(pmu->cpus);
+
+		/* Make the evsel. */
+		evsel = perf_evsel__new(&attr);
+		if (!evsel) {
+			pr_err("User space counter reading for PMU %s [Failed to allocate evsel]\n",
+				pmu->name);
+			ret = TEST_FAIL;
+			goto cleanup;
+		}
+
+		err = perf_evsel__open(evsel, NULL, threads);
+		if (err) {
+			pr_err("User space counter reading for PMU %s [Failed to open evsel]\n",
+				pmu->name);
+			ret = TEST_SKIP;
+			goto cleanup;
+		}
+		opened = true;
+		err = perf_evsel__mmap(evsel, 0);
+		if (err) {
+			pr_err("User space counter reading for PMU %s [Failed to mmap evsel]\n",
+				pmu->name);
+			ret = TEST_FAIL;
+			goto cleanup;
+		}
+		mapped = true;
+
+		pc = perf_evsel__mmap_base(evsel, 0, 0);
+		if (!pc) {
+			pr_err("User space counter reading for PMU %s [Failed to get mmaped address]\n",
+				pmu->name);
+			ret = TEST_FAIL;
+			goto cleanup;
+		}
+
+		if (saved_user_read_state == USER_READ_UNKNOWN)
+			rdpmc_supported = pc->cap_user_rdpmc && pc->index;
+		else
+			rdpmc_supported = (enabled == USER_READ_ENABLED);
+
+		if (rdpmc_supported && (!pc->cap_user_rdpmc || !pc->index)) {
+			pr_err("User space counter reading for PMU %s [Failed unexpected supported counter access %d %d]\n",
+				pmu->name, pc->cap_user_rdpmc, pc->index);
+			ret = TEST_FAIL;
+			goto cleanup;
+		}
+
+		if (!rdpmc_supported && pc->cap_user_rdpmc) {
+			pr_err("User space counter reading for PMU %s [Failed unexpected unsupported counter access %d]\n",
+				pmu->name, pc->cap_user_rdpmc);
+			ret = TEST_FAIL;
+			goto cleanup;
+		}
+
+		if (rdpmc_supported && pc->pmc_width < 32) {
+			pr_err("User space counter reading for PMU %s [Failed width not set %d]\n",
+				pmu->name, pc->pmc_width);
+			ret = TEST_FAIL;
+			goto cleanup;
+		}
+
+		perf_evsel__read(evsel, 0, 0, &counts);
+		if (rdpmc_supported && counts.val == 0) {
+			pr_err("User space counter reading for PMU %s [Failed read]\n", pmu->name);
+			ret = TEST_FAIL;
+			goto cleanup;
+		}
+
+		for (int i = 0; i < 5; i++) {
+			volatile int count = 0x10000 << i;
+			__u64 start, end, last = 0;
+
+			pr_debug("\tloop = %u, ", count);
+
+			perf_evsel__read(evsel, 0, 0, &counts);
+			start = counts.val;
+
+			while (count--) ;
+
+			perf_evsel__read(evsel, 0, 0, &counts);
+			end = counts.val;
+
+			if ((end - start) < last) {
+				pr_err("User space counter reading for PMU %s [Failed invalid counter data: end=%llu start=%llu last= %llu]\n",
+					pmu->name, end, start, last);
+				ret = TEST_FAIL;
+				goto cleanup;
+			}
+			last = end - start;
+			pr_debug("count = %llu\n", last);
+		}
+		pr_debug("User space counter reading for PMU %s [Success]\n", pmu->name);
+cleanup:
+		if (mapped)
+			perf_evsel__munmap(evsel);
+		if (opened)
+			perf_evsel__close(evsel);
+		perf_evsel__delete(evsel);
+
+		/* If the affinity was changed, then put it back to all CPUs. */
+		if (pmu->cpus != NULL) {
+			struct perf_cpu_map *cpus = cpu_map__online();
+
+			cpu_map__set_affinity(cpus);
+			perf_cpu_map__put(cpus);
+		}
+		set_user_read(pmu, saved_user_read_state);
+	}
+	perf_thread_map__put(threads);
+	return ret;
+}
+
+static int test__mmap_user_read_instr(struct test_suite *test __maybe_unused,
+				      int subtest __maybe_unused)
+{
+	return test_stat_user_read(PERF_COUNT_HW_INSTRUCTIONS, USER_READ_ENABLED);
+}
+
+static int test__mmap_user_read_cycles(struct test_suite *test __maybe_unused,
+				       int subtest __maybe_unused)
+{
+	return test_stat_user_read(PERF_COUNT_HW_CPU_CYCLES, USER_READ_ENABLED);
+}
+
+static int test__mmap_user_read_instr_disabled(struct test_suite *test __maybe_unused,
+					       int subtest __maybe_unused)
+{
+	return test_stat_user_read(PERF_COUNT_HW_INSTRUCTIONS, USER_READ_DISABLED);
+}
+
+static int test__mmap_user_read_cycles_disabled(struct test_suite *test __maybe_unused,
+						int subtest __maybe_unused)
+{
+	return test_stat_user_read(PERF_COUNT_HW_CPU_CYCLES, USER_READ_DISABLED);
+}
+
+static struct test_case tests__basic_mmap[] = {
+	TEST_CASE_REASON("Read samples using the mmap interface",
+			 basic_mmap,
+			 "permissions"),
+	TEST_CASE_REASON_EXCLUSIVE("User space counter reading of instructions",
+			 mmap_user_read_instr,
+#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__) || \
+			 (defined(__riscv) && __riscv_xlen == 64)
+			 "permissions"
+#else
+			 "unsupported"
+#endif
+		),
+	TEST_CASE_REASON_EXCLUSIVE("User space counter reading of cycles",
+			 mmap_user_read_cycles,
+#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__) || \
+			 (defined(__riscv) && __riscv_xlen == 64)
+			 "permissions"
+#else
+			 "unsupported"
+#endif
+		),
+	TEST_CASE_REASON_EXCLUSIVE("User space counter disabling instructions",
+			 mmap_user_read_instr_disabled,
+#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__) || \
+			 (defined(__riscv) && __riscv_xlen == 64)
+			 "permissions"
+#else
+			 "unsupported"
+#endif
+		),
+	TEST_CASE_REASON_EXCLUSIVE("User space counter disabling cycles",
+			 mmap_user_read_cycles_disabled,
+#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__) || \
+			 (defined(__riscv) && __riscv_xlen == 64)
+			 "permissions"
+#else
+			 "unsupported"
+#endif
+		),
+	{	.name = NULL, }
+};
+
+struct test_suite suite__basic_mmap = {
+	.desc = "mmap interface tests",
+	.test_cases = tests__basic_mmap,
+};