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Commit 425d23f8 authored by Todd Kjos's avatar Todd Kjos
Browse files

FROMLIST: binder: protect proc->nodes with inner lock 

(from https://patchwork.kernel.org/patch/9817783/

)

When locks for binder_ref handling are added, proc->nodes
will need to be modified while holding the outer lock

Change-Id: I7daf5a51d83cdf6ac31a3728b3ea3e6ab94bf2e7
Signed-off-by: default avatarTodd Kjos <tkjos@google.com>
parent cbcbbd68

drivers/android/binder.c

+89 −23
Original line number Diff line number Diff line
@@ -312,6 +312,7 @@ struct binder_error { 
 * @work:                 worklist element for node work

 *                        (protected by @proc->inner_lock)

 * @rb_node:              element for proc->nodes tree

 *                        (protected by @proc->inner_lock)

 * @dead_node:            element for binder_dead_nodes list

 *                        (protected by binder_dead_nodes_lock)

 * @proc:                 binder_proc that owns this node
@@ -469,6 +470,7 @@ enum binder_deferred_state { 
 * @threads:              rbtree of binder_threads in this proc

 * @nodes:                rbtree of binder nodes associated with

 *                        this proc ordered by node->ptr

 *                        (protected by @inner_lock)

 * @refs_by_desc:         rbtree of refs ordered by ref->desc

 * @refs_by_node:         rbtree of refs ordered by ref->node

 * @pid                   PID of group_leader of process
@@ -855,7 +857,7 @@ static void 
binder_defer_work(struct binder_proc *proc, enum binder_deferred_state defer);

static void binder_free_thread(struct binder_thread *thread);

static void binder_free_proc(struct binder_proc *proc);

static void binder_inc_node_tmpref(struct binder_node *node);

static void binder_inc_node_tmpref_ilocked(struct binder_node *node);



static int task_get_unused_fd_flags(struct binder_proc *proc, int flags)

{
@@ -937,12 +939,14 @@ static void binder_set_nice(long nice) 
	binder_user_error("%d RLIMIT_NICE not set\n", current->pid);

}



static struct binder_node *binder_get_node(struct binder_proc *proc,

static struct binder_node *binder_get_node_ilocked(struct binder_proc *proc,

						   binder_uintptr_t ptr)

{

	struct rb_node *n = proc->nodes.rb_node;

	struct binder_node *node;



	BUG_ON(!spin_is_locked(&proc->inner_lock));



	while (n) {

		node = rb_entry(n, struct binder_node, rb_node);
@@ -956,14 +960,27 @@ static struct binder_node *binder_get_node(struct binder_proc *proc, 
			 * to ensure node stays alive until

			 * call to binder_put_node()

			 */

			binder_inc_node_tmpref(node);

			binder_inc_node_tmpref_ilocked(node);

			return node;

		}

	}

	return NULL;

}



static struct binder_node *binder_new_node(struct binder_proc *proc,

static struct binder_node *binder_get_node(struct binder_proc *proc,

					   binder_uintptr_t ptr)

{

	struct binder_node *node;



	binder_inner_proc_lock(proc);

	node = binder_get_node_ilocked(proc, ptr);

	binder_inner_proc_unlock(proc);

	return node;

}



static struct binder_node *binder_init_node_ilocked(

						struct binder_proc *proc,

						struct binder_node *new_node,

						struct flat_binder_object *fp)

{

	struct rb_node **p = &proc->nodes.rb_node;
@@ -973,7 +990,9 @@ static struct binder_node *binder_new_node(struct binder_proc *proc, 
	binder_uintptr_t cookie = fp ? fp->cookie : 0;

	__u32 flags = fp ? fp->flags : 0;



	BUG_ON(!spin_is_locked(&proc->inner_lock));

	while (*p) {



		parent = *p;

		node = rb_entry(parent, struct binder_node, rb_node);
@@ -981,13 +1000,17 @@ static struct binder_node *binder_new_node(struct binder_proc *proc, 
			p = &(*p)->rb_left;

		else if (ptr > node->ptr)

			p = &(*p)->rb_right;

		else

			return NULL;

		else {

			/*

			 * A matching node is already in

			 * the rb tree. Abandon the init

			 * and return it.

			 */

			binder_inc_node_tmpref_ilocked(node);

			return node;

		}



	node = kzalloc(sizeof(*node), GFP_KERNEL);

	if (node == NULL)

		return NULL;

	}

	node = new_node;

	binder_stats_created(BINDER_STAT_NODE);

	node->tmp_refs++;

	rb_link_node(&node->rb_node, parent, p);
@@ -1006,6 +1029,27 @@ static struct binder_node *binder_new_node(struct binder_proc *proc, 
		     "%d:%d node %d u%016llx c%016llx created\n",

		     proc->pid, current->pid, node->debug_id,

		     (u64)node->ptr, (u64)node->cookie);



	return node;

}



static struct binder_node *binder_new_node(struct binder_proc *proc,

					   struct flat_binder_object *fp)

{

	struct binder_node *node;

	struct binder_node *new_node = kzalloc(sizeof(*node), GFP_KERNEL);



	if (!new_node)

		return NULL;

	binder_inner_proc_lock(proc);

	node = binder_init_node_ilocked(proc, new_node, fp);

	binder_inner_proc_unlock(proc);

	if (node != new_node)

		/*

		 * The node was already added by another thread

		 */

		kfree(new_node);



	return node;

}
@@ -4420,6 +4464,7 @@ static void binder_deferred_release(struct binder_proc *proc) 


	nodes = 0;

	incoming_refs = 0;

	binder_inner_proc_lock(proc);

	while ((n = rb_first(&proc->nodes))) {

		struct binder_node *node;
@@ -4430,10 +4475,13 @@ static void binder_deferred_release(struct binder_proc *proc) 
		 * calling binder_node_release() which will either

		 * kfree() the node or call binder_put_node()

		 */

		binder_inc_node_tmpref(node);

		binder_inc_node_tmpref_ilocked(node);

		rb_erase(&node->rb_node, &proc->nodes);

		binder_inner_proc_unlock(proc);

		incoming_refs = binder_node_release(node, incoming_refs);

		binder_inner_proc_lock(proc);

	}

	binder_inner_proc_unlock(proc);



	outgoing_refs = 0;

	while ((n = rb_first(&proc->refs_by_desc))) {
@@ -4618,7 +4666,7 @@ static void print_binder_thread_ilocked(struct seq_file *m, 
		m->count = start_pos;

}



static void print_binder_node_nlocked(struct seq_file *m,

static void print_binder_node_nilocked(struct seq_file *m,

				       struct binder_node *node)

{

	struct binder_ref *ref;
@@ -4626,6 +4674,8 @@ static void print_binder_node_nlocked(struct seq_file *m, 
	int count;



	WARN_ON(!spin_is_locked(&node->lock));

	if (node->proc)

		WARN_ON(!spin_is_locked(&node->proc->inner_lock));



	count = 0;

	hlist_for_each_entry(ref, &node->refs, node_entry)
@@ -4643,11 +4693,9 @@ static void print_binder_node_nlocked(struct seq_file *m, 
	}

	seq_puts(m, "\n");

	if (node->proc) {

		binder_inner_proc_lock(node->proc);

		list_for_each_entry(w, &node->async_todo, entry)

			print_binder_work_ilocked(m, "    ",

					  "    pending async transaction", w);

		binder_inner_proc_unlock(node->proc);

	}

}
@@ -4669,6 +4717,7 @@ static void print_binder_proc(struct seq_file *m, 
	struct rb_node *n;

	size_t start_pos = m->count;

	size_t header_pos;

	struct binder_node *last_node = NULL;



	seq_printf(m, "proc %d\n", proc->pid);

	seq_printf(m, "context %s\n", proc->context->name);
@@ -4678,15 +4727,30 @@ static void print_binder_proc(struct seq_file *m, 
	for (n = rb_first(&proc->threads); n != NULL; n = rb_next(n))

		print_binder_thread_ilocked(m, rb_entry(n, struct binder_thread,

						rb_node), print_all);

	binder_inner_proc_unlock(proc);



	for (n = rb_first(&proc->nodes); n != NULL; n = rb_next(n)) {

		struct binder_node *node = rb_entry(n, struct binder_node,

						    rb_node);

		binder_node_lock(node);

		if (print_all || node->has_async_transaction)

			print_binder_node_nlocked(m, node);

		binder_node_unlock(node);

		/*

		 * take a temporary reference on the node so it

		 * survives and isn't removed from the tree

		 * while we print it.

		 */

		binder_inc_node_tmpref_ilocked(node);

		/* Need to drop inner lock to take node lock */

		binder_inner_proc_unlock(proc);

		if (last_node)

			binder_put_node(last_node);

		binder_node_inner_lock(node);

		print_binder_node_nilocked(m, node);

		binder_node_inner_unlock(node);

		last_node = node;

		binder_inner_proc_lock(proc);

	}

	binder_inner_proc_unlock(proc);

	if (last_node)

		binder_put_node(last_node);



	if (print_all) {

		for (n = rb_first(&proc->refs_by_desc);

		     n != NULL;
@@ -4822,8 +4886,10 @@ static void print_binder_proc_stats(struct seq_file *m, 
			proc->ready_threads,

			binder_alloc_get_free_async_space(&proc->alloc));

	count = 0;

	binder_inner_proc_lock(proc);

	for (n = rb_first(&proc->nodes); n != NULL; n = rb_next(n))

		count++;

	binder_inner_proc_unlock(proc);

	seq_printf(m, "  nodes: %d\n", count);

	count = 0;

	strong = 0;
@@ -4877,7 +4943,7 @@ static int binder_state_show(struct seq_file *m, void *unused) 
		if (last_node)

			binder_put_node(last_node);

		binder_node_lock(node);

		print_binder_node_nlocked(m, node);

		print_binder_node_nilocked(m, node);

		binder_node_unlock(node);

		last_node = node;

		spin_lock(&binder_dead_nodes_lock);