diff options
| author | Martijn Coenen <maco@android.com> | 2018-02-16 09:47:15 +0100 |
|---|---|---|
| committer | Todd Kjos <tkjos@google.com> | 2020-01-29 15:07:41 -0800 |
| commit | 6027926dac2c92b07182c1e2162bd8346105ce54 (patch) | |
| tree | e6c50ffbd76341d81b7aa3df683971841640660c | |
| parent | 57053ed1aacd59fe0d5acbaef0939782c5adf289 (diff) | |
ANDROID: binder: synchronize_rcu() when using POLLFREE.ASB-2020-02-05_4.4-o-mr1
commit 5eeb2ca02a2f6084fc57ae5c244a38baab07033a upstream.
To prevent races with ep_remove_waitqueue() removing the
waitqueue at the same time.
Change-Id: I2ac8d0029725ae555b58d72cece7de8d08f564da
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: Mattias Nissler <mnissler@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 592209fb36f0..c590187766e7 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -4508,6 +4508,15 @@ 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); |