diff options
| author | Martijn Coenen <maco@android.com> | 2018-02-16 09:47:15 +0100 |
|---|---|---|
| committer | Moyster <oysterized@gmail.com> | 2018-11-29 10:59:46 +0100 |
| commit | cee4ad025c853ede3709424871708504cfdc0d01 (patch) | |
| tree | 163f1ebc90b39ccb33a3c76ed6911a03b2206cc6 | |
| parent | bf11084a5868dc372e08c9fbfed683c709bf7e36 (diff) | |
UPSTREAM: ANDROID: binder: synchronize_rcu() when using POLLFREE.
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/android/binder.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 75416cac2..5ee6727c8 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -4463,6 +4463,15 @@ 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); |