Merge tag 'trace-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - Added option for per CPU threads to the hwlat tracer

 - Have hwlat tracer handle hotplug CPUs

 - New tracer: osnoise, that detects latency caused by interrupts,
   softirqs and scheduling of other tasks.

 - Added timerlat tracer that creates a thread and measures in detail
   what sources of latency it has for wake ups.

 - Removed the "success" field of the sched_wakeup trace event. This has
   been hardcoded as "1" since 2015, no tooling should be looking at it
   now. If one exists, we can revert this commit, fix that tool and try
   to remove it again in the future.

 - tgid mapping fixed to handle more than PID_MAX_DEFAULT pids/tgids.

 - New boot command line option "tp_printk_stop", as tp_printk causes
   trace events to write to console. When user space starts, this can
   easily live lock the system. Having a boot option to stop just after
   boot up is useful to prevent that from happening.

 - Have ftrace_dump_on_oops boot command line option take numbers that
   match the numbers shown in /proc/sys/kernel/ftrace_dump_on_oops.

 - Bootconfig clean ups, fixes and enhancements.

 - New ktest script that tests bootconfig options.

 - Add tracepoint_probe_register_may_exist() to register a tracepoint
   without triggering a WARN*() if it already exists. BPF has a path
   from user space that can do this. All other paths are considered a
   bug.

 - Small clean ups and fixes

* tag 'trace-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (49 commits)
  tracing: Resize tgid_map to pid_max, not PID_MAX_DEFAULT
  tracing: Simplify & fix saved_tgids logic
  treewide: Add missing semicolons to __assign_str uses
  tracing: Change variable type as bool for clean-up
  trace/timerlat: Fix indentation on timerlat_main()
  trace/osnoise: Make 'noise' variable s64 in run_osnoise()
  tracepoint: Add tracepoint_probe_register_may_exist() for BPF tracing
  tracing: Fix spelling in osnoise tracer "interferences" -> "interference"
  Documentation: Fix a typo on trace/osnoise-tracer
  trace/osnoise: Fix return value on osnoise_init_hotplug_support
  trace/osnoise: Make interval u64 on osnoise_main
  trace/osnoise: Fix 'no previous prototype' warnings
  tracing: Have osnoise_main() add a quiescent state for task rcu
  seq_buf: Make trace_seq_putmem_hex() support data longer than 8
  seq_buf: Fix overflow in seq_buf_putmem_hex()
  trace/osnoise: Support hotplug operations
  trace/hwlat: Support hotplug operations
  trace/hwlat: Protect kdata->kthread with get/put_online_cpus
  trace: Add timerlat tracer
  trace: Add osnoise tracer
  ...

2 files changed, 64 insertions, 20 deletions

diff --git a/lib/bootconfig.c b/lib/bootconfig.c
index 9f8c70a98fcf..927017431fb6 100644
--- a/lib/bootconfig.c
+++ b/lib/bootconfig.c
@@ -156,7 +156,7 @@ xbc_node_find_child(struct xbc_node *parent, const char *key)
 	struct xbc_node *node;
 
 	if (parent)
-		node = xbc_node_get_child(parent);
+		node = xbc_node_get_subkey(parent);
 	else
 		node = xbc_root_node();
 
@@ -164,7 +164,7 @@ xbc_node_find_child(struct xbc_node *parent, const char *key)
 		if (!xbc_node_match_prefix(node, &key))
 			node = xbc_node_get_next(node);
 		else if (*key != '\0')
-			node = xbc_node_get_child(node);
+			node = xbc_node_get_subkey(node);
 		else
 			break;
 	}
@@ -274,6 +274,8 @@ int __init xbc_node_compose_key_after(struct xbc_node *root,
 struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
 						 struct xbc_node *node)
 {
+	struct xbc_node *next;
+
 	if (unlikely(!xbc_data))
 		return NULL;
 
@@ -282,6 +284,13 @@ struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
 		if (!node)
 			node = xbc_nodes;
 	} else {
+		/* Leaf node may have a subkey */
+		next = xbc_node_get_subkey(node);
+		if (next) {
+			node = next;
+			goto found;
+		}
+
 		if (node == root)	/* @root was a leaf, no child node. */
 			return NULL;
 
@@ -296,6 +305,7 @@ struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
 		node = xbc_node_get_next(node);
 	}
 
+found:
 	while (node && !xbc_node_is_leaf(node))
 		node = xbc_node_get_child(node);
 
@@ -367,18 +377,28 @@ static inline __init struct xbc_node *xbc_last_sibling(struct xbc_node *node)
 	return node;
 }
 
-static struct xbc_node * __init xbc_add_sibling(char *data, u32 flag)
+static inline __init struct xbc_node *xbc_last_child(struct xbc_node *node)
+{
+	while (node->child)
+		node = xbc_node_get_child(node);
+
+	return node;
+}
+
+static struct xbc_node * __init __xbc_add_sibling(char *data, u32 flag, bool head)
 {
 	struct xbc_node *sib, *node = xbc_add_node(data, flag);
 
 	if (node) {
 		if (!last_parent) {
+			/* Ignore @head in this case */
 			node->parent = XBC_NODE_MAX;
 			sib = xbc_last_sibling(xbc_nodes);
 			sib->next = xbc_node_index(node);
 		} else {
 			node->parent = xbc_node_index(last_parent);
-			if (!last_parent->child) {
+			if (!last_parent->child || head) {
+				node->next = last_parent->child;
 				last_parent->child = xbc_node_index(node);
 			} else {
 				sib = xbc_node_get_child(last_parent);
@@ -392,6 +412,16 @@ static struct xbc_node * __init xbc_add_sibling(char *data, u32 flag)
 	return node;
 }
 
+static inline struct xbc_node * __init xbc_add_sibling(char *data, u32 flag)
+{
+	return __xbc_add_sibling(data, flag, false);
+}
+
+static inline struct xbc_node * __init xbc_add_head_sibling(char *data, u32 flag)
+{
+	return __xbc_add_sibling(data, flag, true);
+}
+
 static inline __init struct xbc_node *xbc_add_child(char *data, u32 flag)
 {
 	struct xbc_node *node = xbc_add_sibling(data, flag);
@@ -517,17 +547,20 @@ static int __init xbc_parse_array(char **__v)
 	char *next;
 	int c = 0;
 
+	if (last_parent->child)
+		last_parent = xbc_node_get_child(last_parent);
+
 	do {
 		c = __xbc_parse_value(__v, &next);
 		if (c < 0)
 			return c;
 
-		node = xbc_add_sibling(*__v, XBC_VALUE);
+		node = xbc_add_child(*__v, XBC_VALUE);
 		if (!node)
 			return -ENOMEM;
 		*__v = next;
 	} while (c == ',');
-	node->next = 0;
+	node->child = 0;
 
 	return c;
 }
@@ -557,8 +590,9 @@ static int __init __xbc_add_key(char *k)
 		node = find_match_node(xbc_nodes, k);
 	else {
 		child = xbc_node_get_child(last_parent);
+		/* Since the value node is the first child, skip it. */
 		if (child && xbc_node_is_value(child))
-			return xbc_parse_error("Subkey is mixed with value", k);
+			child = xbc_node_get_next(child);
 		node = find_match_node(child, k);
 	}
 
@@ -601,23 +635,29 @@ static int __init xbc_parse_kv(char **k, char *v, int op)
 	if (ret)
 		return ret;
 
-	child = xbc_node_get_child(last_parent);
-	if (child) {
-		if (xbc_node_is_key(child))
-			return xbc_parse_error("Value is mixed with subkey", v);
-		else if (op == '=')
-			return xbc_parse_error("Value is redefined", v);
-	}
-
 	c = __xbc_parse_value(&v, &next);
 	if (c < 0)
 		return c;
 
-	if (op == ':' && child) {
-		xbc_init_node(child, v, XBC_VALUE);
-	} else if (!xbc_add_sibling(v, XBC_VALUE))
+	child = xbc_node_get_child(last_parent);
+	if (child && xbc_node_is_value(child)) {
+		if (op == '=')
+			return xbc_parse_error("Value is redefined", v);
+		if (op == ':') {
+			unsigned short nidx = child->next;
+
+			xbc_init_node(child, v, XBC_VALUE);
+			child->next = nidx;	/* keep subkeys */
+			goto array;
+		}
+		/* op must be '+' */
+		last_parent = xbc_last_child(child);
+	}
+	/* The value node should always be the first child */
+	if (!xbc_add_head_sibling(v, XBC_VALUE))
 		return -ENOMEM;
 
+array:
 	if (c == ',') {	/* Array */
 		c = xbc_parse_array(&next);
 		if (c < 0)
diff --git a/lib/seq_buf.c b/lib/seq_buf.c
index 707453f5d58e..6dafde851333 100644
--- a/lib/seq_buf.c
+++ b/lib/seq_buf.c
@@ -229,8 +229,10 @@ int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
 
 	WARN_ON(s->size == 0);
 
+	BUILD_BUG_ON(MAX_MEMHEX_BYTES * 2 >= HEX_CHARS);
+
 	while (len) {
-		start_len = min(len, HEX_CHARS - 1);
+		start_len = min(len, MAX_MEMHEX_BYTES);
 #ifdef __BIG_ENDIAN
 		for (i = 0, j = 0; i < start_len; i++) {
 #else
@@ -243,12 +245,14 @@ int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
 			break;
 
 		/* j increments twice per loop */
-		len -= j / 2;
 		hex[j++] = ' ';
 
 		seq_buf_putmem(s, hex, j);
 		if (seq_buf_has_overflowed(s))
 			return -1;
+
+		len -= start_len;
+		data += start_len;
 	}
 	return 0;
 }