linux-kernel - [PATCH 11/13] ANDROID: binder: don't enqueue death notifications to thread todo.

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Date:   Fri, 25 Aug 2017 11:33:33 +0200
From:   Martijn Coenen <maco@...roid.com>
To:     gregkh@...uxfoundation.org, john.stultz@...aro.org,
        tkjos@...gle.com, arve@...roid.com, amit.pundir@...aro.org
Cc:     linux-kernel@...r.kernel.org, devel@...verdev.osuosl.org,
        maco@...gle.com, malchev@...gle.com, ccross@...roid.com,
        Martijn Coenen <maco@...roid.com>
Subject: [PATCH 11/13] ANDROID: binder: don't enqueue death notifications to thread todo.

This allows userspace to request death notifications without
having to worry about getting an immediate callback on the same
thread; one scenario where this would be problematic is if the
death recipient handler grabs a lock that was already taken
earlier (eg as part of a nested transaction).

Signed-off-by: Martijn Coenen <maco@...roid.com>
---
 drivers/android/binder.c | 22 ++++++----------------
 1 file changed, 6 insertions(+), 16 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index e8a70a7c789c..12ab16bb676c 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3668,22 +3668,12 @@ static int binder_thread_write(struct binder_proc *proc,
 				ref->death = death;
 				if (ref->node->proc == NULL) {
 					ref->death->work.type = BINDER_WORK_DEAD_BINDER;
-					if (thread->looper &
-					    (BINDER_LOOPER_STATE_REGISTERED |
-					     BINDER_LOOPER_STATE_ENTERED))
-						binder_enqueue_work(
-							proc,
-							&ref->death->work,
-							&thread->todo);
-					else {
-						binder_inner_proc_lock(proc);
-						binder_enqueue_work_ilocked(
-							&ref->death->work,
-							&proc->todo);
-						binder_wakeup_proc_ilocked(
-							proc);
-						binder_inner_proc_unlock(proc);
-					}
+
+					binder_inner_proc_lock(proc);
+					binder_enqueue_work_ilocked(
+						&ref->death->work, &proc->todo);
+					binder_wakeup_proc_ilocked(proc);
+					binder_inner_proc_unlock(proc);
 				}
 			} else {
 				if (ref->death == NULL) {
-- 
2.14.1.480.gb18f417b89-goog