1 files changed, 211 insertions, 54 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 3c1384bc5c5a..f8b80b5bab71 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -87,6 +87,7 @@ void __init disable_tracing_selftest(const char *reason)
 /* Pipe tracepoints to printk */
 struct trace_iterator *tracepoint_print_iter;
 int tracepoint_printk;
+static bool tracepoint_printk_stop_on_boot __initdata;
 static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key);
 
 /* For tracers that don't implement custom flags */
@@ -197,12 +198,12 @@ __setup("ftrace=", set_cmdline_ftrace);
 
 static int __init set_ftrace_dump_on_oops(char *str)
 {
-	if (*str++ != '=' || !*str) {
+	if (*str++ != '=' || !*str || !strcmp("1", str)) {
 		ftrace_dump_on_oops = DUMP_ALL;
 		return 1;
 	}
 
-	if (!strcmp("orig_cpu", str)) {
+	if (!strcmp("orig_cpu", str) || !strcmp("2", str)) {
 		ftrace_dump_on_oops = DUMP_ORIG;
                 return 1;
         }
@@ -257,6 +258,13 @@ static int __init set_tracepoint_printk(char *str)
 }
 __setup("tp_printk", set_tracepoint_printk);
 
+static int __init set_tracepoint_printk_stop(char *str)
+{
+	tracepoint_printk_stop_on_boot = true;
+	return 1;
+}
+__setup("tp_printk_stop_on_boot", set_tracepoint_printk_stop);
+
 unsigned long long ns2usecs(u64 nsec)
 {
 	nsec += 500;
@@ -1683,8 +1691,7 @@ static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
 unsigned long __read_mostly	tracing_thresh;
 static const struct file_operations tracing_max_lat_fops;
 
-#if (defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)) && \
-	defined(CONFIG_FSNOTIFY)
+#ifdef LATENCY_FS_NOTIFY
 
 static struct workqueue_struct *fsnotify_wq;
 
@@ -2185,8 +2192,15 @@ void tracing_reset_all_online_cpus(void)
 	}
 }
 
+/*
+ * The tgid_map array maps from pid to tgid; i.e. the value stored at index i
+ * is the tgid last observed corresponding to pid=i.
+ */
 static int *tgid_map;
 
+/* The maximum valid index into tgid_map. */
+static size_t tgid_map_max;
+
 #define SAVED_CMDLINES_DEFAULT 128
 #define NO_CMDLINE_MAP UINT_MAX
 static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
@@ -2459,24 +2473,41 @@ void trace_find_cmdline(int pid, char comm[])
 	preempt_enable();
 }
 
+static int *trace_find_tgid_ptr(int pid)
+{
+	/*
+	 * Pairs with the smp_store_release in set_tracer_flag() to ensure that
+	 * if we observe a non-NULL tgid_map then we also observe the correct
+	 * tgid_map_max.
+	 */
+	int *map = smp_load_acquire(&tgid_map);
+
+	if (unlikely(!map || pid > tgid_map_max))
+		return NULL;
+
+	return &map[pid];
+}
+
 int trace_find_tgid(int pid)
 {
-	if (unlikely(!tgid_map || !pid || pid > PID_MAX_DEFAULT))
-		return 0;
+	int *ptr = trace_find_tgid_ptr(pid);
 
-	return tgid_map[pid];
+	return ptr ? *ptr : 0;
 }
 
 static int trace_save_tgid(struct task_struct *tsk)
 {
+	int *ptr;
+
 	/* treat recording of idle task as a success */
 	if (!tsk->pid)
 		return 1;
 
-	if (unlikely(!tgid_map || tsk->pid > PID_MAX_DEFAULT))
+	ptr = trace_find_tgid_ptr(tsk->pid);
+	if (!ptr)
 		return 0;
 
-	tgid_map[tsk->pid] = tsk->tgid;
+	*ptr = tsk->tgid;
 	return 1;
 }
 
@@ -2730,9 +2761,45 @@ trace_event_buffer_lock_reserve(struct trace_buffer **current_rb,
 	if (!tr->no_filter_buffering_ref &&
 	    (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) &&
 	    (entry = this_cpu_read(trace_buffered_event))) {
-		/* Try to use the per cpu buffer first */
+		/*
+		 * Filtering is on, so try to use the per cpu buffer first.
+		 * This buffer will simulate a ring_buffer_event,
+		 * where the type_len is zero and the array[0] will
+		 * hold the full length.
+		 * (see include/linux/ring-buffer.h for details on
+		 *  how the ring_buffer_event is structured).
+		 *
+		 * Using a temp buffer during filtering and copying it
+		 * on a matched filter is quicker than writing directly
+		 * into the ring buffer and then discarding it when
+		 * it doesn't match. That is because the discard
+		 * requires several atomic operations to get right.
+		 * Copying on match and doing nothing on a failed match
+		 * is still quicker than no copy on match, but having
+		 * to discard out of the ring buffer on a failed match.
+		 */
+		int max_len = PAGE_SIZE - struct_size(entry, array, 1);
+
 		val = this_cpu_inc_return(trace_buffered_event_cnt);
-		if ((len < (PAGE_SIZE - sizeof(*entry) - sizeof(entry->array[0]))) && val == 1) {
+
+		/*
+		 * Preemption is disabled, but interrupts and NMIs
+		 * can still come in now. If that happens after
+		 * the above increment, then it will have to go
+		 * back to the old method of allocating the event
+		 * on the ring buffer, and if the filter fails, it
+		 * will have to call ring_buffer_discard_commit()
+		 * to remove it.
+		 *
+		 * Need to also check the unlikely case that the
+		 * length is bigger than the temp buffer size.
+		 * If that happens, then the reserve is pretty much
+		 * guaranteed to fail, as the ring buffer currently
+		 * only allows events less than a page. But that may
+		 * change in the future, so let the ring buffer reserve
+		 * handle the failure in that case.
+		 */
+		if (val == 1 && likely(len <= max_len)) {
 			trace_event_setup(entry, type, trace_ctx);
 			entry->array[0] = len;
 			return entry;
@@ -5172,6 +5239,8 @@ int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
 
 int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
 {
+	int *map;
+
 	if ((mask == TRACE_ITER_RECORD_TGID) ||
 	    (mask == TRACE_ITER_RECORD_CMD))
 		lockdep_assert_held(&event_mutex);
@@ -5194,10 +5263,19 @@ int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
 		trace_event_enable_cmd_record(enabled);
 
 	if (mask == TRACE_ITER_RECORD_TGID) {
-		if (!tgid_map)
-			tgid_map = kvcalloc(PID_MAX_DEFAULT + 1,
-					   sizeof(*tgid_map),
-					   GFP_KERNEL);
+		if (!tgid_map) {
+			tgid_map_max = pid_max;
+			map = kvcalloc(tgid_map_max + 1, sizeof(*tgid_map),
+				       GFP_KERNEL);
+
+			/*
+			 * Pairs with smp_load_acquire() in
+			 * trace_find_tgid_ptr() to ensure that if it observes
+			 * the tgid_map we just allocated then it also observes
+			 * the corresponding tgid_map_max value.
+			 */
+			smp_store_release(&tgid_map, map);
+		}
 		if (!tgid_map) {
 			tr->trace_flags &= ~TRACE_ITER_RECORD_TGID;
 			return -ENOMEM;
@@ -5609,37 +5687,16 @@ static const struct file_operations tracing_readme_fops = {
 
 static void *saved_tgids_next(struct seq_file *m, void *v, loff_t *pos)
 {
-	int *ptr = v;
-
-	if (*pos || m->count)
-		ptr++;
-
-	(*pos)++;
-
-	for (; ptr <= &tgid_map[PID_MAX_DEFAULT]; ptr++) {
-		if (trace_find_tgid(*ptr))
-			return ptr;
-	}
+	int pid = ++(*pos);
 
-	return NULL;
+	return trace_find_tgid_ptr(pid);
 }
 
 static void *saved_tgids_start(struct seq_file *m, loff_t *pos)
 {
-	void *v;
-	loff_t l = 0;
-
-	if (!tgid_map)
-		return NULL;
+	int pid = *pos;
 
-	v = &tgid_map[0];
-	while (l <= *pos) {
-		v = saved_tgids_next(m, v, &l);
-		if (!v)
-			return NULL;
-	}
-
-	return v;
+	return trace_find_tgid_ptr(pid);
 }
 
 static void saved_tgids_stop(struct seq_file *m, void *v)
@@ -5648,9 +5705,14 @@ static void saved_tgids_stop(struct seq_file *m, void *v)
 
 static int saved_tgids_show(struct seq_file *m, void *v)
 {
-	int pid = (int *)v - tgid_map;
+	int *entry = (int *)v;
+	int pid = entry - tgid_map;
+	int tgid = *entry;
 
-	seq_printf(m, "%d %d\n", pid, trace_find_tgid(pid));
+	if (tgid == 0)
+		return SEQ_SKIP;
+
+	seq_printf(m, "%d %d\n", pid, tgid);
 	return 0;
 }
 
@@ -6135,7 +6197,7 @@ static int __tracing_resize_ring_buffer(struct trace_array *tr,
 ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
 				  unsigned long size, int cpu_id)
 {
-	int ret = size;
+	int ret;
 
 	mutex_lock(&trace_types_lock);
 
@@ -7529,6 +7591,91 @@ static const struct file_operations snapshot_raw_fops = {
 
 #endif /* CONFIG_TRACER_SNAPSHOT */
 
+/*
+ * trace_min_max_write - Write a u64 value to a trace_min_max_param struct
+ * @filp: The active open file structure
+ * @ubuf: The userspace provided buffer to read value into
+ * @cnt: The maximum number of bytes to read
+ * @ppos: The current "file" position
+ *
+ * This function implements the write interface for a struct trace_min_max_param.
+ * The filp->private_data must point to a trace_min_max_param structure that
+ * defines where to write the value, the min and the max acceptable values,
+ * and a lock to protect the write.
+ */
+static ssize_t
+trace_min_max_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos)
+{
+	struct trace_min_max_param *param = filp->private_data;
+	u64 val;
+	int err;
+
+	if (!param)
+		return -EFAULT;
+
+	err = kstrtoull_from_user(ubuf, cnt, 10, &val);
+	if (err)
+		return err;
+
+	if (param->lock)
+		mutex_lock(param->lock);
+
+	if (param->min && val < *param->min)
+		err = -EINVAL;
+
+	if (param->max && val > *param->max)
+		err = -EINVAL;
+
+	if (!err)
+		*param->val = val;
+
+	if (param->lock)
+		mutex_unlock(param->lock);
+
+	if (err)
+		return err;
+
+	return cnt;
+}
+
+/*
+ * trace_min_max_read - Read a u64 value from a trace_min_max_param struct
+ * @filp: The active open file structure
+ * @ubuf: The userspace provided buffer to read value into
+ * @cnt: The maximum number of bytes to read
+ * @ppos: The current "file" position
+ *
+ * This function implements the read interface for a struct trace_min_max_param.
+ * The filp->private_data must point to a trace_min_max_param struct with valid
+ * data.
+ */
+static ssize_t
+trace_min_max_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
+{
+	struct trace_min_max_param *param = filp->private_data;
+	char buf[U64_STR_SIZE];
+	int len;
+	u64 val;
+
+	if (!param)
+		return -EFAULT;
+
+	val = *param->val;
+
+	if (cnt > sizeof(buf))
+		cnt = sizeof(buf);
+
+	len = snprintf(buf, sizeof(buf), "%llu\n", val);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
+}
+
+const struct file_operations trace_min_max_fops = {
+	.open		= tracing_open_generic,
+	.read		= trace_min_max_read,
+	.write		= trace_min_max_write,
+};
+
 #define TRACING_LOG_ERRS_MAX	8
 #define TRACING_LOG_LOC_MAX	128
 
@@ -9532,6 +9679,8 @@ static __init int tracer_init_tracefs(void)
 	return 0;
 }
 
+fs_initcall(tracer_init_tracefs);
+
 static int trace_panic_handler(struct notifier_block *this,
 			       unsigned long event, void *unused)
 {
@@ -9952,7 +10101,7 @@ void __init trace_init(void)
 	trace_event_init();
 }
 
-__init static int clear_boot_tracer(void)
+__init static void clear_boot_tracer(void)
 {
 	/*
 	 * The default tracer at boot buffer is an init section.
@@ -9962,26 +10111,21 @@ __init static int clear_boot_tracer(void)
 	 * about to be freed.
 	 */
 	if (!default_bootup_tracer)
-		return 0;
+		return;
 
 	printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
 	       default_bootup_tracer);
 	default_bootup_tracer = NULL;
-
-	return 0;
 }
 
-fs_initcall(tracer_init_tracefs);
-late_initcall_sync(clear_boot_tracer);
-
 #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
-__init static int tracing_set_default_clock(void)
+__init static void tracing_set_default_clock(void)
 {
 	/* sched_clock_stable() is determined in late_initcall */
 	if (!trace_boot_clock && !sched_clock_stable()) {
 		if (security_locked_down(LOCKDOWN_TRACEFS)) {
 			pr_warn("Can not set tracing clock due to lockdown\n");
-			return -EPERM;
+			return;
 		}
 
 		printk(KERN_WARNING
@@ -9991,8 +10135,21 @@ __init static int tracing_set_default_clock(void)
 		       "on the kernel command line\n");
 		tracing_set_clock(&global_trace, "global");
 	}
+}
+#else
+static inline void tracing_set_default_clock(void) { }
+#endif
+
+__init static int late_trace_init(void)
+{
+	if (tracepoint_printk && tracepoint_printk_stop_on_boot) {
+		static_key_disable(&tracepoint_printk_key.key);
+		tracepoint_printk = 0;
+	}
 
+	tracing_set_default_clock();
+	clear_boot_tracer();
 	return 0;
 }
-late_initcall_sync(tracing_set_default_clock);
-#endif
+
+late_initcall_sync(late_trace_init);