RE: Fix memory leak in binder

[Tu, Xiaobing]

-----Original Message-----
From: Tu, Xiaobing 
Sent: Monday, October 15, 2012 3:03 PM
To: 'ccross@xxxxxxxxxxx'; 'davej@xxxxxxxxxx'; 'akpm@xxxxxxxxxxxxxxxxxxxx'; 'mingo@xxxxxxx'; 'rusty@xxxxxxxxxxxxxxx'; 'a.p.zijlstra@xxxxxxxxx'; 'linux-kernel@xxxxxxxxxxxxxxx'; 'rostedt@xxxxxxxxxxx'
Cc: Zhang, Di; Ma, Xindong
Subject: Fix memory leak in binder

After enabling kmemleak and run monkey, following memleak is reported:
unreferenced object 0xeed27f80 (size 64):
  comm "Binder_8", pid 641, jiffies 4294946341 (age 2275.810s)
  hex dump (first 32 bytes):
    4f dd 00 00 84 7f d2 ee 84 7f d2 ee 01 00 00 00  O...............
    00 00 00 00 00 00 00 00 00 aa 4c d7 00 00 00 00  ..........L.....
  backtrace:
    [<c184fabc>] kmemleak_alloc+0x3c/0xa0
    [<c12f391e>] kmem_cache_alloc_trace+0x9e/0x180
    [<c1668bb5>] binder_thread_write+0xcf5/0x23a0
    [<c166b091>] binder_ioctl+0x1f1/0x530
    [<c130dcf6>] do_vfs_ioctl+0x86/0x5e0
    [<c130e282>] sys_ioctl+0x32/0x60
    [<c1872e01>] syscall_call+0x7/0xb
    [<ffffffff>] 0xffffffff

The work item in async_todo list is not freed when binder released.
Also the async transaction should also be freed in binder_release_work.

Signed-off-by: Leon Ma <xindong.ma@xxxxxxxxx>
Signed-off-by: Di Zhang <di.zhang@xxxxxxxxx>
---
 drivers/staging/android/binder.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/drivers/staging/android/binder.c b/drivers/staging/android/binder.c
index 7df2a89..d23de68 100644
--- a/drivers/staging/android/binder.c
+++ b/drivers/staging/android/binder.c
@@ -1281,6 +1281,7 @@ static void binder_send_failed_reply(struct binder_transaction *t,
 					"already\n", target_thread->proc->pid,
 					target_thread->pid,
 					target_thread->return_error);
+				kfree(t);
 			}
 			return;
 		} else {
@@ -2509,6 +2510,11 @@ static void binder_release_work(struct list_head *list)
 			t = container_of(w, struct binder_transaction, work);
 			if (t->buffer->target_node && !(t->flags & TF_ONE_WAY))
 				binder_send_failed_reply(t, BR_DEAD_REPLY);
+			else {
+				t->buffer->transaction = NULL;
+				kfree(t);
+				binder_stats_deleted(BINDER_STAT_TRANSACTION);
+			}
 		} break;
 		case BINDER_WORK_TRANSACTION_COMPLETE: {
 			kfree(w);
@@ -2982,6 +2988,7 @@ static void binder_deferred_release(struct binder_proc *proc)
 
 		nodes++;
 		rb_erase(&node->rb_node, &proc->nodes);
+		binder_release_work(&node->async_todo);
 		list_del_init(&node->work.entry);
 		if (hlist_empty(&node->refs)) {
 			kfree(node);
-- 
1.7.6

Br
XiaoBing Tu
PSI@System Integration Shanghai



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