diff options
| author | Martijn Coenen <maco@android.com> | 2018-02-16 09:47:15 +0100 |
|---|---|---|
| committer | Todd Kjos <tkjos@google.com> | 2020-01-29 15:06:32 -0800 |
| commit | 4f7792a0ca36fd500b31ed2d2fd9d87e74cd814c (patch) | |
| tree | 7efd61304bfe486059348593a77aceff5f4830bf | |
| parent | d01296343a2ee185fa918fcc6335fc283bf5f122 (diff) | |
UPSTREAM: ANDROID: binder: synchronize_rcu() when using POLLFREE.ASB-2020-02-05_3.18-o-mr1
To prevent races with ep_remove_waitqueue() removing the
waitqueue at the same time.
Reported-by: syzbot+a2a3c4909716e271487e@syzkaller.appspotmail.com
Signed-off-by: Martijn Coenen <maco@android.com>
Cc: stable <stable@vger.kernel.org> # 4.14+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 5eeb2ca02a2f6084fc57ae5c244a38baab07033a)
Change-Id: Ia0089448079c78d0ab0b57303faf838e9e5ee797
| -rw-r--r-- | drivers/staging/android/binder.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/staging/android/binder.c b/drivers/staging/android/binder.c index ba35e17af023..410224088efc 100644 --- a/drivers/staging/android/binder.c +++ b/drivers/staging/android/binder.c @@ -4495,6 +4495,15 @@ static int binder_thread_release(struct binder_proc *proc, binder_inner_proc_unlock(thread->proc); + /* + * This is needed to avoid races between wake_up_poll() above and + * and ep_remove_waitqueue() called for other reasons (eg the epoll file + * descriptor being closed); ep_remove_waitqueue() holds an RCU read + * lock, so we can be sure it's done after calling synchronize_rcu(). + */ + if (thread->looper & BINDER_LOOPER_STATE_POLL) + synchronize_rcu(); + if (send_reply) binder_send_failed_reply(send_reply, BR_DEAD_REPLY); binder_release_work(proc, &thread->todo); |