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, 495 insertions, 0 deletions

diff --git a/tools/perf/util/dsos.c b/tools/perf/util/dsos.c
new file mode 100644
index 000000000..e927e707a
--- /dev/null
+++ b/tools/perf/util/dsos.c
@@ -0,0 +1,495 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "debug.h"
+#include "dsos.h"
+#include "dso.h"
+#include "util.h"
+#include "vdso.h"
+#include "namespaces.h"
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <symbol.h> // filename__read_build_id
+#include <unistd.h>
+
+void dsos__init(struct dsos *dsos)
+{
+	init_rwsem(&dsos->lock);
+
+	dsos->cnt = 0;
+	dsos->allocated = 0;
+	dsos->dsos = NULL;
+	dsos->sorted = true;
+}
+
+static void dsos__purge(struct dsos *dsos)
+{
+	down_write(&dsos->lock);
+
+	for (unsigned int i = 0; i < dsos->cnt; i++) {
+		struct dso *dso = dsos->dsos[i];
+
+		dso__set_dsos(dso, NULL);
+		dso__put(dso);
+	}
+
+	zfree(&dsos->dsos);
+	dsos->cnt = 0;
+	dsos->allocated = 0;
+	dsos->sorted = true;
+
+	up_write(&dsos->lock);
+}
+
+void dsos__exit(struct dsos *dsos)
+{
+	dsos__purge(dsos);
+	exit_rwsem(&dsos->lock);
+}
+
+
+static int __dsos__for_each_dso(struct dsos *dsos,
+				int (*cb)(struct dso *dso, void *data),
+				void *data)
+{
+	for (unsigned int i = 0; i < dsos->cnt; i++) {
+		struct dso *dso = dsos->dsos[i];
+		int err;
+
+		err = cb(dso, data);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+struct dsos__read_build_ids_cb_args {
+	bool with_hits;
+	bool have_build_id;
+};
+
+static int dsos__read_build_ids_cb(struct dso *dso, void *data)
+{
+	struct dsos__read_build_ids_cb_args *args = data;
+	struct nscookie nsc;
+	struct build_id bid = { .size = 0, };
+
+	if (args->with_hits && !dso__hit(dso) && !dso__is_vdso(dso))
+		return 0;
+	if (dso__has_build_id(dso)) {
+		args->have_build_id = true;
+		return 0;
+	}
+	nsinfo__mountns_enter(dso__nsinfo(dso), &nsc);
+	if (filename__read_build_id(dso__long_name(dso), &bid) > 0) {
+		dso__set_build_id(dso, &bid);
+		args->have_build_id = true;
+	} else if (errno == ENOENT && dso__nsinfo(dso)) {
+		char *new_name = dso__filename_with_chroot(dso, dso__long_name(dso));
+
+		if (new_name && filename__read_build_id(new_name, &bid) > 0) {
+			dso__set_build_id(dso, &bid);
+			args->have_build_id = true;
+		}
+		free(new_name);
+	}
+	nsinfo__mountns_exit(&nsc);
+	return 0;
+}
+
+bool dsos__read_build_ids(struct dsos *dsos, bool with_hits)
+{
+	struct dsos__read_build_ids_cb_args args = {
+		.with_hits = with_hits,
+		.have_build_id = false,
+	};
+
+	dsos__for_each_dso(dsos, dsos__read_build_ids_cb, &args);
+	return args.have_build_id;
+}
+
+static int __dso__cmp_long_name(const char *long_name, const struct dso_id *id,
+				const struct dso *b)
+{
+	int rc = strcmp(long_name, dso__long_name(b));
+	return rc ?: dso_id__cmp(id, dso__id_const(b));
+}
+
+static int __dso__cmp_short_name(const char *short_name, const struct dso_id *id,
+				 const struct dso *b)
+{
+	int rc = strcmp(short_name, dso__short_name(b));
+	return rc ?: dso_id__cmp(id, dso__id_const(b));
+}
+
+static int dsos__cmp_long_name_id_short_name(const void *va, const void *vb)
+{
+	const struct dso *a = *((const struct dso **)va);
+	const struct dso *b = *((const struct dso **)vb);
+	int rc = strcmp(dso__long_name(a), dso__long_name(b));
+
+	if (!rc) {
+		rc = dso_id__cmp(dso__id_const(a), dso__id_const(b));
+		if (!rc)
+			rc = strcmp(dso__short_name(a), dso__short_name(b));
+	}
+	return rc;
+}
+
+struct dsos__key {
+	const char *long_name;
+	const struct dso_id *id;
+};
+
+static int dsos__cmp_key_long_name_id(const void *vkey, const void *vdso)
+{
+	const struct dsos__key *key = vkey;
+	const struct dso *dso = *((const struct dso **)vdso);
+
+	return __dso__cmp_long_name(key->long_name, key->id, dso);
+}
+
+/*
+ * Find a matching entry and/or link current entry to RB tree.
+ * Either one of the dso or name parameter must be non-NULL or the
+ * function will not work.
+ */
+static struct dso *__dsos__find_by_longname_id(struct dsos *dsos,
+					       const char *name,
+					       const struct dso_id *id,
+					       bool write_locked)
+	SHARED_LOCKS_REQUIRED(dsos->lock)
+{
+	struct dsos__key key = {
+		.long_name = name,
+		.id = id,
+	};
+	struct dso **res;
+
+	if (dsos->dsos == NULL)
+		return NULL;
+
+	if (!dsos->sorted) {
+		if (!write_locked) {
+			struct dso *dso;
+
+			up_read(&dsos->lock);
+			down_write(&dsos->lock);
+			dso = __dsos__find_by_longname_id(dsos, name, id,
+							  /*write_locked=*/true);
+			up_write(&dsos->lock);
+			down_read(&dsos->lock);
+			return dso;
+		}
+		qsort(dsos->dsos, dsos->cnt, sizeof(struct dso *),
+		      dsos__cmp_long_name_id_short_name);
+		dsos->sorted = true;
+	}
+
+	res = bsearch(&key, dsos->dsos, dsos->cnt, sizeof(struct dso *),
+		      dsos__cmp_key_long_name_id);
+	if (!res)
+		return NULL;
+
+	return dso__get(*res);
+}
+
+int __dsos__add(struct dsos *dsos, struct dso *dso)
+{
+	if (!dso)
+		return -EINVAL;
+
+	if (dsos->cnt == dsos->allocated) {
+		unsigned int to_allocate = 2;
+		struct dso **temp;
+
+		if (dsos->allocated > 0)
+			to_allocate = dsos->allocated * 2;
+		temp = realloc(dsos->dsos, sizeof(struct dso *) * to_allocate);
+		if (!temp)
+			return -ENOMEM;
+		dsos->dsos = temp;
+		dsos->allocated = to_allocate;
+	}
+	if (!dsos->sorted) {
+		dsos->dsos[dsos->cnt++] = dso__get(dso);
+	} else {
+		int low = 0, high = dsos->cnt - 1;
+		int insert = dsos->cnt; /* Default to inserting at the end. */
+
+		while (low <= high) {
+			int mid = low + (high - low) / 2;
+			int cmp = dsos__cmp_long_name_id_short_name(&dsos->dsos[mid], &dso);
+
+			if (cmp < 0) {
+				low = mid + 1;
+			} else {
+				high = mid - 1;
+				insert = mid;
+			}
+		}
+		memmove(&dsos->dsos[insert + 1], &dsos->dsos[insert],
+			(dsos->cnt - insert) * sizeof(struct dso *));
+		dsos->cnt++;
+		dsos->dsos[insert] = dso__get(dso);
+	}
+	dso__set_dsos(dso, dsos);
+	return 0;
+}
+
+int dsos__add(struct dsos *dsos, struct dso *dso)
+{
+	int ret;
+
+	down_write(&dsos->lock);
+	ret = __dsos__add(dsos, dso);
+	up_write(&dsos->lock);
+	return ret;
+}
+
+struct dsos__find_id_cb_args {
+	const char *name;
+	const struct dso_id *id;
+	struct dso *res;
+};
+
+static int dsos__find_id_cb(struct dso *dso, void *data)
+{
+	struct dsos__find_id_cb_args *args = data;
+
+	if (__dso__cmp_short_name(args->name, args->id, dso) == 0) {
+		args->res = dso__get(dso);
+		return 1;
+	}
+	return 0;
+
+}
+
+static struct dso *__dsos__find_id(struct dsos *dsos, const char *name, const struct dso_id *id,
+				   bool cmp_short, bool write_locked)
+	SHARED_LOCKS_REQUIRED(dsos->lock)
+{
+	struct dso *res;
+
+	if (cmp_short) {
+		struct dsos__find_id_cb_args args = {
+			.name = name,
+			.id = id,
+			.res = NULL,
+		};
+
+		__dsos__for_each_dso(dsos, dsos__find_id_cb, &args);
+		return args.res;
+	}
+	res = __dsos__find_by_longname_id(dsos, name, id, write_locked);
+	return res;
+}
+
+struct dso *dsos__find(struct dsos *dsos, const char *name, bool cmp_short)
+{
+	struct dso *res;
+
+	down_read(&dsos->lock);
+	res = __dsos__find_id(dsos, name, &dso_id_empty, cmp_short, /*write_locked=*/false);
+	up_read(&dsos->lock);
+	return res;
+}
+
+static void dso__set_basename(struct dso *dso)
+{
+	bool allocated = false;
+	const char *base;
+	int tid;
+
+	if (perf_pid_map_tid(dso__long_name(dso), &tid)) {
+		char *jitname;
+
+		if (asprintf(&jitname, "[JIT] tid %d", tid) < 0)
+			return;
+		allocated = true;
+		base = jitname;
+	} else {
+		base = perf_basename(dso__long_name(dso));
+	}
+	dso__set_short_name(dso, base, allocated);
+}
+
+static struct dso *__dsos__addnew_id(struct dsos *dsos, const char *name, const struct dso_id *id)
+{
+	struct dso *dso = dso__new_id(name, id);
+
+	if (dso != NULL) {
+		/*
+		 * The dsos lock is held on entry, so rename the dso before
+		 * adding it to avoid needing to take the dsos lock again to say
+		 * the array isn't sorted.
+		 */
+		dso__set_basename(dso);
+		__dsos__add(dsos, dso);
+	}
+	return dso;
+}
+
+static struct dso *__dsos__findnew_id(struct dsos *dsos, const char *name, const struct dso_id *id)
+	SHARED_LOCKS_REQUIRED(dsos->lock)
+{
+	struct dso *dso = __dsos__find_id(dsos, name, id, false, /*write_locked=*/true);
+
+	if (dso)
+		__dso__improve_id(dso, id);
+
+	return dso ? dso : __dsos__addnew_id(dsos, name, id);
+}
+
+struct dso *dsos__findnew_id(struct dsos *dsos, const char *name, const struct dso_id *id)
+{
+	struct dso *dso;
+	down_write(&dsos->lock);
+	dso = __dsos__findnew_id(dsos, name, id);
+	up_write(&dsos->lock);
+	return dso;
+}
+
+struct dsos__fprintf_buildid_cb_args {
+	FILE *fp;
+	bool (*skip)(struct dso *dso, int parm);
+	int parm;
+	size_t ret;
+};
+
+static int dsos__fprintf_buildid_cb(struct dso *dso, void *data)
+{
+	struct dsos__fprintf_buildid_cb_args *args = data;
+	char sbuild_id[SBUILD_ID_SIZE];
+
+	if (args->skip && args->skip(dso, args->parm))
+		return 0;
+	build_id__snprintf(dso__bid(dso), sbuild_id, sizeof(sbuild_id));
+	args->ret += fprintf(args->fp, "%-40s %s\n", sbuild_id, dso__long_name(dso));
+	return 0;
+}
+
+size_t dsos__fprintf_buildid(struct dsos *dsos, FILE *fp,
+			       bool (*skip)(struct dso *dso, int parm), int parm)
+{
+	struct dsos__fprintf_buildid_cb_args args = {
+		.fp = fp,
+		.skip = skip,
+		.parm = parm,
+		.ret = 0,
+	};
+
+	dsos__for_each_dso(dsos, dsos__fprintf_buildid_cb, &args);
+	return args.ret;
+}
+
+struct dsos__fprintf_cb_args {
+	FILE *fp;
+	size_t ret;
+};
+
+static int dsos__fprintf_cb(struct dso *dso, void *data)
+{
+	struct dsos__fprintf_cb_args *args = data;
+
+	args->ret += dso__fprintf(dso, args->fp);
+	return 0;
+}
+
+size_t dsos__fprintf(struct dsos *dsos, FILE *fp)
+{
+	struct dsos__fprintf_cb_args args = {
+		.fp = fp,
+		.ret = 0,
+	};
+
+	dsos__for_each_dso(dsos, dsos__fprintf_cb, &args);
+	return args.ret;
+}
+
+static int dsos__hit_all_cb(struct dso *dso, void *data __maybe_unused)
+{
+	dso__set_hit(dso);
+	return 0;
+}
+
+int dsos__hit_all(struct dsos *dsos)
+{
+	return dsos__for_each_dso(dsos, dsos__hit_all_cb, NULL);
+}
+
+struct dso *dsos__findnew_module_dso(struct dsos *dsos,
+				     struct machine *machine,
+				     struct kmod_path *m,
+				     const char *filename)
+{
+	struct dso *dso;
+
+	down_write(&dsos->lock);
+
+	dso = __dsos__find_id(dsos, m->name, &dso_id_empty, /*cmp_short=*/true,
+			      /*write_locked=*/true);
+	if (dso) {
+		up_write(&dsos->lock);
+		return dso;
+	}
+	/*
+	 * Failed to find the dso so create it. Change the name before adding it
+	 * to the array, to avoid unnecessary sorts and potential locking
+	 * issues.
+	 */
+	dso = dso__new_id(m->name, /*id=*/NULL);
+	if (!dso) {
+		up_write(&dsos->lock);
+		return NULL;
+	}
+	dso__set_basename(dso);
+	dso__set_module_info(dso, m, machine);
+	dso__set_long_name(dso,	strdup(filename), true);
+	dso__set_kernel(dso, DSO_SPACE__KERNEL);
+	__dsos__add(dsos, dso);
+
+	up_write(&dsos->lock);
+	return dso;
+}
+
+static int dsos__find_kernel_dso_cb(struct dso *dso, void *data)
+{
+	struct dso **res = data;
+	/*
+	 * The cpumode passed to is_kernel_module is not the cpumode of *this*
+	 * event. If we insist on passing correct cpumode to is_kernel_module,
+	 * we should record the cpumode when we adding this dso to the linked
+	 * list.
+	 *
+	 * However we don't really need passing correct cpumode.  We know the
+	 * correct cpumode must be kernel mode (if not, we should not link it
+	 * onto kernel_dsos list).
+	 *
+	 * Therefore, we pass PERF_RECORD_MISC_CPUMODE_UNKNOWN.
+	 * is_kernel_module() treats it as a kernel cpumode.
+	 */
+	if (!dso__kernel(dso) ||
+	    is_kernel_module(dso__long_name(dso), PERF_RECORD_MISC_CPUMODE_UNKNOWN))
+		return 0;
+
+	*res = dso__get(dso);
+	return 1;
+}
+
+struct dso *dsos__find_kernel_dso(struct dsos *dsos)
+{
+	struct dso *res = NULL;
+
+	dsos__for_each_dso(dsos, dsos__find_kernel_dso_cb, &res);
+	return res;
+}
+
+int dsos__for_each_dso(struct dsos *dsos, int (*cb)(struct dso *dso, void *data), void *data)
+{
+	int err;
+
+	down_read(&dsos->lock);
+	err = __dsos__for_each_dso(dsos, cb, data);
+	up_read(&dsos->lock);
+	return err;
+}