FAILED: patch "[PATCH] ANDROID: binder: prevent transactions into own process." failed to apply to 4.9-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 7aa135fcf26377f92dc0680a57566b4c7f3e281b Mon Sep 17 00:00:00 2001
From: Martijn Coenen <maco@android.com>
Date: Wed, 28 Mar 2018 11:14:50 +0200
Subject: [PATCH] ANDROID: binder: prevent transactions into own process.

This can't happen with normal nodes (because you can't get a ref
to a node you own), but it could happen with the context manager;
to make the behavior consistent with regular nodes, reject
transactions into the context manager by the process owning it.

Reported-by: syzbot+09e05aba06723a94d43d@syzkaller.appspotmail.com
Signed-off-by: Martijn Coenen <maco@android.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 764b63a5aade..e578eee31589 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2839,6 +2839,14 @@ static void binder_transaction(struct binder_proc *proc,
 			else
 				return_error = BR_DEAD_REPLY;
 			mutex_unlock(&context->context_mgr_node_lock);
+			if (target_node && target_proc == proc) {
+				binder_user_error("%d:%d got transaction to context manager from process owning it\n",
+						  proc->pid, thread->pid);
+				return_error = BR_FAILED_REPLY;
+				return_error_param = -EINVAL;
+				return_error_line = __LINE__;
+				goto err_invalid_target_handle;
+			}
 		}
 		if (!target_node) {
 			/*