Re: [syzbot] Re: [syzbot] [kernel?] upstream test error: KASAN: slab-use-after-free Write in binderfs_evict_inode

[syzbot <syzbot+353d7b75658a95aa955a@syzkaller.appspotmail.com>]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: Re: [syzbot] [kernel?] upstream test error: KASAN: slab-use-after-free Write in binderfs_evict_inode
Author: lizhi.xu@windriver.com

#syz test

diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
index 94c6446604fc..21fd218796d6 100644
--- a/drivers/android/binderfs.c
+++ b/drivers/android/binderfs.c
@@ -271,13 +271,13 @@ static void binderfs_evict_inode(struct inode *inode)
 	mutex_lock(&binderfs_minors_mutex);
 	--info->device_count;
 	ida_free(&binderfs_minors, device->miscdev.minor);
-	mutex_unlock(&binderfs_minors_mutex);
 
 	if (refcount_dec_and_test(&device->ref)) {
 		hlist_del_init(&device->hlist);
 		kfree(device->context.name);
 		kfree(device);
 	}
+	mutex_unlock(&binderfs_minors_mutex);
 }
 
 static int binderfs_fs_context_parse_param(struct fs_context *fc,