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, 369 insertions, 0 deletions

diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
new file mode 100644
index 000000000..358e70c4f
--- /dev/null
+++ b/tools/perf/util/mmap.c
@@ -0,0 +1,369 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2011-2017, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
+ *
+ * Parts came from evlist.c builtin-{top,stat,record}.c, see those files for further
+ * copyright notes.
+ */
+
+#include <sys/mman.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <asm/bug.h>
+#include <linux/zalloc.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h> // sysconf()
+#include <perf/mmap.h>
+#ifdef HAVE_LIBNUMA_SUPPORT
+#include <numaif.h>
+#endif
+#include "cpumap.h"
+#include "debug.h"
+#include "event.h"
+#include "mmap.h"
+#include "../perf.h"
+#include <internal/lib.h> /* page_size */
+#include <linux/bitmap.h>
+
+#define MASK_SIZE 1023
+void mmap_cpu_mask__scnprintf(struct mmap_cpu_mask *mask, const char *tag)
+{
+	char buf[MASK_SIZE + 1];
+	size_t len;
+
+	len = bitmap_scnprintf(mask->bits, mask->nbits, buf, MASK_SIZE);
+	buf[len] = '\0';
+	pr_debug("%p: %s mask[%zd]: %s\n", mask, tag, mask->nbits, buf);
+}
+
+size_t mmap__mmap_len(struct mmap *map)
+{
+	return perf_mmap__mmap_len(&map->core);
+}
+
+int __weak auxtrace_mmap__mmap(struct auxtrace_mmap *mm __maybe_unused,
+			       struct auxtrace_mmap_params *mp __maybe_unused,
+			       void *userpg __maybe_unused,
+			       int fd __maybe_unused)
+{
+	return 0;
+}
+
+void __weak auxtrace_mmap__munmap(struct auxtrace_mmap *mm __maybe_unused)
+{
+}
+
+void __weak auxtrace_mmap_params__init(struct auxtrace_mmap_params *mp __maybe_unused,
+				       off_t auxtrace_offset __maybe_unused,
+				       unsigned int auxtrace_pages __maybe_unused,
+				       bool auxtrace_overwrite __maybe_unused)
+{
+}
+
+void __weak auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp __maybe_unused,
+					  struct evlist *evlist __maybe_unused,
+					  struct evsel *evsel __maybe_unused,
+					  int idx __maybe_unused)
+{
+}
+
+#ifdef HAVE_AIO_SUPPORT
+static int perf_mmap__aio_enabled(struct mmap *map)
+{
+	return map->aio.nr_cblocks > 0;
+}
+
+#ifdef HAVE_LIBNUMA_SUPPORT
+static int perf_mmap__aio_alloc(struct mmap *map, int idx)
+{
+	map->aio.data[idx] = mmap(NULL, mmap__mmap_len(map), PROT_READ|PROT_WRITE,
+				  MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
+	if (map->aio.data[idx] == MAP_FAILED) {
+		map->aio.data[idx] = NULL;
+		return -1;
+	}
+
+	return 0;
+}
+
+static void perf_mmap__aio_free(struct mmap *map, int idx)
+{
+	if (!map->aio.data || !map->aio.data[idx])
+		return;
+	munmap(map->aio.data[idx], mmap__mmap_len(map));
+	map->aio.data[idx] = NULL;
+}
+
+static int perf_mmap__aio_bind(struct mmap *map, int idx, struct perf_cpu cpu, int affinity)
+{
+	void *data;
+	size_t mmap_len;
+	unsigned long *node_mask;
+	unsigned long node_index;
+	int err = 0;
+
+	if (affinity != PERF_AFFINITY_SYS && cpu__max_node() > 1) {
+		int node;
+
+		data = map->aio.data[idx];
+		mmap_len = mmap__mmap_len(map);
+		node = cpu__get_node(cpu);
+		/* -1 sign-extends to ULONG_MAX, wrapping bitmap_zalloc(0) and OOB __set_bit */
+		if (node < 0)
+			return 0;
+		node_index = node;
+		node_mask = bitmap_zalloc(node_index + 1);
+		if (!node_mask) {
+			pr_err("Failed to allocate node mask for mbind: error %m\n");
+			return -1;
+		}
+		__set_bit(node_index, node_mask);
+		if (mbind(data, mmap_len, MPOL_BIND, node_mask, node_index + 1 + 1, 0)) {
+			pr_err("Failed to bind [%p-%p] AIO buffer to node %lu: error %m\n",
+				data, data + mmap_len, node_index);
+			err = -1;
+		}
+		bitmap_free(node_mask);
+	}
+
+	return err;
+}
+#else /* !HAVE_LIBNUMA_SUPPORT */
+static int perf_mmap__aio_alloc(struct mmap *map, int idx)
+{
+	map->aio.data[idx] = malloc(mmap__mmap_len(map));
+	if (map->aio.data[idx] == NULL)
+		return -1;
+
+	return 0;
+}
+
+static void perf_mmap__aio_free(struct mmap *map, int idx)
+{
+	if (!map->aio.data)
+		return;
+	zfree(&(map->aio.data[idx]));
+}
+
+static int perf_mmap__aio_bind(struct mmap *map __maybe_unused, int idx __maybe_unused,
+		struct perf_cpu cpu __maybe_unused, int affinity __maybe_unused)
+{
+	return 0;
+}
+#endif
+
+static int perf_mmap__aio_mmap(struct mmap *map, struct mmap_params *mp)
+{
+	int delta_max, i, prio, ret;
+
+	map->aio.nr_cblocks = mp->nr_cblocks;
+	if (map->aio.nr_cblocks) {
+		map->aio.aiocb = calloc(map->aio.nr_cblocks, sizeof(struct aiocb *));
+		if (!map->aio.aiocb) {
+			pr_debug2("failed to allocate aiocb for data buffer, error %m\n");
+			return -1;
+		}
+		map->aio.cblocks = calloc(map->aio.nr_cblocks, sizeof(struct aiocb));
+		if (!map->aio.cblocks) {
+			pr_debug2("failed to allocate cblocks for data buffer, error %m\n");
+			return -1;
+		}
+		map->aio.data = calloc(map->aio.nr_cblocks, sizeof(void *));
+		if (!map->aio.data) {
+			pr_debug2("failed to allocate data buffer, error %m\n");
+			return -1;
+		}
+		delta_max = sysconf(_SC_AIO_PRIO_DELTA_MAX);
+		for (i = 0; i < map->aio.nr_cblocks; ++i) {
+			ret = perf_mmap__aio_alloc(map, i);
+			if (ret == -1) {
+				pr_debug2("failed to allocate data buffer area, error %m");
+				return -1;
+			}
+			ret = perf_mmap__aio_bind(map, i, map->core.cpu, mp->affinity);
+			if (ret == -1)
+				return -1;
+			/*
+			 * Use cblock.aio_fildes value different from -1
+			 * to denote started aio write operation on the
+			 * cblock so it requires explicit record__aio_sync()
+			 * call prior the cblock may be reused again.
+			 */
+			map->aio.cblocks[i].aio_fildes = -1;
+			/*
+			 * Allocate cblocks with priority delta to have
+			 * faster aio write system calls because queued requests
+			 * are kept in separate per-prio queues and adding
+			 * a new request will iterate thru shorter per-prio
+			 * list. Blocks with numbers higher than
+			 *  _SC_AIO_PRIO_DELTA_MAX go with priority 0.
+			 */
+			prio = delta_max - i;
+			map->aio.cblocks[i].aio_reqprio = prio >= 0 ? prio : 0;
+		}
+	}
+
+	return 0;
+}
+
+static void perf_mmap__aio_munmap(struct mmap *map)
+{
+	int i;
+
+	for (i = 0; i < map->aio.nr_cblocks; ++i)
+		perf_mmap__aio_free(map, i);
+	if (map->aio.data)
+		zfree(&map->aio.data);
+	zfree(&map->aio.cblocks);
+	zfree(&map->aio.aiocb);
+}
+#else /* !HAVE_AIO_SUPPORT */
+static int perf_mmap__aio_enabled(struct mmap *map __maybe_unused)
+{
+	return 0;
+}
+
+static int perf_mmap__aio_mmap(struct mmap *map __maybe_unused,
+			       struct mmap_params *mp __maybe_unused)
+{
+	return 0;
+}
+
+static void perf_mmap__aio_munmap(struct mmap *map __maybe_unused)
+{
+}
+#endif
+
+void mmap__munmap(struct mmap *map)
+{
+	bitmap_free(map->affinity_mask.bits);
+	map->affinity_mask.bits = NULL;
+	map->affinity_mask.nbits = 0;
+
+	zstd_fini(&map->zstd_data);
+
+	perf_mmap__aio_munmap(map);
+	if (map->data != NULL) {
+		munmap(map->data, mmap__mmap_len(map));
+		map->data = NULL;
+	}
+	auxtrace_mmap__munmap(&map->auxtrace_mmap);
+}
+
+static void build_node_mask(int node, struct mmap_cpu_mask *mask)
+{
+	int idx, nr_cpus;
+	struct perf_cpu cpu;
+	struct perf_cpu_map *cpu_map = cpu_map__online();
+
+	if (!cpu_map)
+		return;
+
+	nr_cpus = perf_cpu_map__nr(cpu_map);
+	for (idx = 0; idx < nr_cpus; idx++) {
+		cpu = perf_cpu_map__cpu(cpu_map, idx); /* map c index to online cpu index */
+		if (cpu__get_node(cpu) == node)
+			__set_bit(cpu.cpu, mask->bits);
+	}
+	perf_cpu_map__put(cpu_map);
+}
+
+static int perf_mmap__setup_affinity_mask(struct mmap *map, struct mmap_params *mp)
+{
+	map->affinity_mask.nbits = cpu__max_cpu().cpu;
+	map->affinity_mask.bits = bitmap_zalloc(map->affinity_mask.nbits);
+	if (!map->affinity_mask.bits)
+		return -1;
+
+	if (mp->affinity == PERF_AFFINITY_NODE && cpu__max_node() > 1)
+		build_node_mask(cpu__get_node(map->core.cpu), &map->affinity_mask);
+	else if (mp->affinity == PERF_AFFINITY_CPU)
+		__set_bit(map->core.cpu.cpu, map->affinity_mask.bits);
+
+	return 0;
+}
+
+int mmap__mmap(struct mmap *map, struct mmap_params *mp, int fd, struct perf_cpu cpu)
+{
+	if (perf_mmap__mmap(&map->core, &mp->core, fd, cpu)) {
+		pr_debug2("failed to mmap perf event ring buffer, error %d\n",
+			  errno);
+		return -1;
+	}
+
+	if (mp->affinity != PERF_AFFINITY_SYS &&
+		perf_mmap__setup_affinity_mask(map, mp)) {
+		pr_debug2("failed to alloc mmap affinity mask, error %d\n",
+			  errno);
+		return -1;
+	}
+
+	if (verbose == 2)
+		mmap_cpu_mask__scnprintf(&map->affinity_mask, "mmap");
+
+	map->core.flush = mp->flush;
+
+	if (zstd_init(&map->zstd_data, mp->comp_level)) {
+		pr_debug2("failed to init mmap compressor, error %d\n", errno);
+		return -1;
+	}
+
+	if (mp->comp_level && !perf_mmap__aio_enabled(map)) {
+		map->data = mmap(NULL, mmap__mmap_len(map), PROT_READ|PROT_WRITE,
+				 MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
+		if (map->data == MAP_FAILED) {
+			pr_debug2("failed to mmap data buffer, error %d\n",
+					errno);
+			map->data = NULL;
+			return -1;
+		}
+	}
+
+	if (auxtrace_mmap__mmap(&map->auxtrace_mmap,
+				&mp->auxtrace_mp, map->core.base, fd))
+		return -1;
+
+	return perf_mmap__aio_mmap(map, mp);
+}
+
+int perf_mmap__push(struct mmap *md, void *to,
+		    int push(struct mmap *map, void *to, void *buf, size_t size))
+{
+	u64 head = perf_mmap__read_head(&md->core);
+	unsigned char *data = md->core.base + page_size;
+	unsigned long size;
+	void *buf;
+	int rc = 0;
+
+	rc = perf_mmap__read_init(&md->core);
+	if (rc < 0)
+		return (rc == -EAGAIN) ? 1 : -1;
+
+	size = md->core.end - md->core.start;
+
+	if ((md->core.start & md->core.mask) + size != (md->core.end & md->core.mask)) {
+		buf = &data[md->core.start & md->core.mask];
+		size = md->core.mask + 1 - (md->core.start & md->core.mask);
+		md->core.start += size;
+
+		if (push(md, to, buf, size) < 0) {
+			rc = -1;
+			goto out;
+		}
+	}
+
+	buf = &data[md->core.start & md->core.mask];
+	size = md->core.end - md->core.start;
+	md->core.start += size;
+
+	if (push(md, to, buf, size) < 0) {
+		rc = -1;
+		goto out;
+	}
+
+	md->core.prev = head;
+	perf_mmap__consume(&md->core);
+out:
+	return rc;
+}