Commit 7bd7b0e6 authored by Todd Kjos's avatar Todd Kjos Committed by Greg Kroah-Hartman
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binder: protect proc->threads with inner_lock 



proc->threads will need to be accessed with higher
locks of other processes held so use proc->inner_lock
to protect it. proc->tmp_ref now needs to be protected
by proc->inner_lock.

Signed-off-by: default avatarTodd Kjos <tkjos@google.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent da0fa9e4

drivers/android/binder.c

+63 −24
Original line number Diff line number Diff line
@@ -469,6 +469,7 @@ enum binder_deferred_state { 
 * struct binder_proc - binder process bookkeeping

 * @proc_node:            element for binder_procs list

 * @threads:              rbtree of binder_threads in this proc

 *                        (protected by @inner_lock)

 * @nodes:                rbtree of binder nodes associated with

 *                        this proc ordered by node->ptr

 *                        (protected by @inner_lock)
@@ -486,6 +487,7 @@ enum binder_deferred_state { 
 *                        (protected by binder_deferred_lock)

 * @is_dead:              process is dead and awaiting free

 *                        when outstanding transactions are cleaned up

 *                        (protected by @inner_lock)

 * @todo:                 list of work for this process

 *                        (protected by @inner_lock)

 * @wait:                 wait queue head to wait for proc work
@@ -501,6 +503,7 @@ enum binder_deferred_state { 
 * @requested_threads_started: number binder threads started

 * @ready_threads:        number of threads waiting for proc work

 * @tmp_ref:              temporary reference to indicate proc is in use

 *                        (protected by @inner_lock)

 * @default_priority:     default scheduler priority

 *                        (invariant after initialized)

 * @debugfs_entry:        debugfs node
@@ -556,6 +559,7 @@ enum { 
 * @proc:                 binder process for this thread

 *                        (invariant after initialization)

 * @rb_node:              element for proc->threads rbtree

 *                        (protected by @proc->inner_lock)

 * @pid:                  PID for this thread

 *                        (invariant after initialization)

 * @looper:               bitmap of looping state
@@ -576,6 +580,7 @@ enum { 
 *                        always be acquired)

 * @is_dead:              thread is dead and awaiting free

 *                        when outstanding transactions are cleaned up

 *                        (protected by @proc->inner_lock)

 *

 * Bookkeeping structure for binder threads.

 */
@@ -1667,15 +1672,15 @@ static void binder_thread_dec_tmpref(struct binder_thread *thread) 
	/*

	 * atomic is used to protect the counter value while

	 * it cannot reach zero or thread->is_dead is false

	 *

	 * TODO: future patch adds locking to ensure that the

	 * check of tmp_ref and is_dead is done with a lock held

	 */

	binder_inner_proc_lock(thread->proc);

	atomic_dec(&thread->tmp_ref);

	if (thread->is_dead && !atomic_read(&thread->tmp_ref)) {

		binder_inner_proc_unlock(thread->proc);

		binder_free_thread(thread);

		return;

	}

	binder_inner_proc_unlock(thread->proc);

}



/**
@@ -1692,12 +1697,15 @@ static void binder_thread_dec_tmpref(struct binder_thread *thread) 
 */

static void binder_proc_dec_tmpref(struct binder_proc *proc)

{

	binder_inner_proc_lock(proc);

	proc->tmp_ref--;

	if (proc->is_dead && RB_EMPTY_ROOT(&proc->threads) &&

			!proc->tmp_ref) {

		binder_inner_proc_unlock(proc);

		binder_free_proc(proc);

		return;

	}

	binder_inner_proc_unlock(proc);

}



/**
@@ -2480,7 +2488,9 @@ static void binder_transaction(struct binder_proc *proc, 
			return_error_line = __LINE__;

			goto err_dead_binder;

		}

		binder_inner_proc_lock(target_proc);

		target_proc->tmp_ref++;

		binder_inner_proc_unlock(target_proc);

		binder_node_unlock(target_node);

		if (security_binder_transaction(proc->tsk,

						target_proc->tsk) < 0) {
@@ -3854,7 +3864,8 @@ static void binder_release_work(struct binder_proc *proc, 


}



static struct binder_thread *binder_get_thread(struct binder_proc *proc)

static struct binder_thread *binder_get_thread_ilocked(

		struct binder_proc *proc, struct binder_thread *new_thread)

{

	struct binder_thread *thread = NULL;

	struct rb_node *parent = NULL;
@@ -3869,12 +3880,11 @@ static struct binder_thread *binder_get_thread(struct binder_proc *proc) 
		else if (current->pid > thread->pid)

			p = &(*p)->rb_right;

		else

			break;

			return thread;

	}

	if (*p == NULL) {

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

		if (thread == NULL)

	if (!new_thread)

		return NULL;

	thread = new_thread;

	binder_stats_created(BINDER_STAT_THREAD);

	thread->proc = proc;

	thread->pid = current->pid;
@@ -3888,6 +3898,27 @@ static struct binder_thread *binder_get_thread(struct binder_proc *proc) 
	thread->return_error.cmd = BR_OK;

	thread->reply_error.work.type = BINDER_WORK_RETURN_ERROR;

	thread->reply_error.cmd = BR_OK;



	return thread;

}



static struct binder_thread *binder_get_thread(struct binder_proc *proc)

{

	struct binder_thread *thread;

	struct binder_thread *new_thread;



	binder_inner_proc_lock(proc);

	thread = binder_get_thread_ilocked(proc, NULL);

	binder_inner_proc_unlock(proc);

	if (!thread) {

		new_thread = kzalloc(sizeof(*thread), GFP_KERNEL);

		if (new_thread == NULL)

			return NULL;

		binder_inner_proc_lock(proc);

		thread = binder_get_thread_ilocked(proc, new_thread);

		binder_inner_proc_unlock(proc);

		if (thread != new_thread)

			kfree(new_thread);

	}

	return thread;

}
@@ -3918,6 +3949,7 @@ static int binder_thread_release(struct binder_proc *proc, 
	int active_transactions = 0;

	struct binder_transaction *last_t = NULL;



	binder_inner_proc_lock(thread->proc);

	/*

	 * take a ref on the proc so it survives

	 * after we remove this thread from proc->threads.
@@ -3965,6 +3997,7 @@ static int binder_thread_release(struct binder_proc *proc, 
		if (t)

			spin_lock(&t->lock);

	}

	binder_inner_proc_unlock(thread->proc);



	if (send_reply)

		binder_send_failed_reply(send_reply, BR_DEAD_REPLY);
@@ -4338,6 +4371,7 @@ static void binder_deferred_flush(struct binder_proc *proc) 
	struct rb_node *n;

	int wake_count = 0;



	binder_inner_proc_lock(proc);

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

		struct binder_thread *thread = rb_entry(n, struct binder_thread, rb_node);
@@ -4347,6 +4381,7 @@ static void binder_deferred_flush(struct binder_proc *proc) 
			wake_count++;

		}

	}

	binder_inner_proc_unlock(proc);

	wake_up_interruptible_all(&proc->wait);



	binder_debug(BINDER_DEBUG_OPEN_CLOSE,
@@ -4445,6 +4480,7 @@ static void binder_deferred_release(struct binder_proc *proc) 
		context->binder_context_mgr_node = NULL;

	}

	mutex_unlock(&context->context_mgr_node_lock);

	binder_inner_proc_lock(proc);

	/*

	 * Make sure proc stays alive after we

	 * remove all the threads
@@ -4458,13 +4494,14 @@ static void binder_deferred_release(struct binder_proc *proc) 
		struct binder_thread *thread;



		thread = rb_entry(n, struct binder_thread, rb_node);

		binder_inner_proc_unlock(proc);

		threads++;

		active_transactions += binder_thread_release(proc, thread);

		binder_inner_proc_lock(proc);

	}



	nodes = 0;

	incoming_refs = 0;

	binder_inner_proc_lock(proc);

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

		struct binder_node *node;
@@ -4872,10 +4909,13 @@ static void print_binder_proc_stats(struct seq_file *m, 
	struct binder_work *w;

	struct rb_node *n;

	int count, strong, weak;

	size_t free_async_space =

		binder_alloc_get_free_async_space(&proc->alloc);



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

	seq_printf(m, "context %s\n", proc->context->name);

	count = 0;

	binder_inner_proc_lock(proc);

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

		count++;

	seq_printf(m, "  threads: %d\n", count);
@@ -4884,9 +4924,8 @@ static void print_binder_proc_stats(struct seq_file *m, 
			"  free async space %zd\n", proc->requested_threads,

			proc->requested_threads_started, proc->max_threads,

			proc->ready_threads,

			binder_alloc_get_free_async_space(&proc->alloc));

			free_async_space);

	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);