diff options
| author | Martijn Coenen <maco@android.com> | 2018-02-16 09:47:15 +0100 |
|---|---|---|
| committer | Todd Kjos <tkjos@google.com> | 2020-01-29 14:53:42 -0800 |
| commit | 93166c112b64d9045e4529d90fc723d1cf8d3f6e (patch) | |
| tree | 4bb962e00737bc4ab1de4f7c7d3dc71bb6e2f57a | |
| parent | 8ab673e4cdcdbf39d2755dd48385c10761daa75b (diff) | |
UPSTREAM: ANDROID: binder: synchronize_rcu() when using POLLFREE.ASB-2020-02-05_3.18-o-release
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 9d0927dbeb2d..a9651fb3d8ba 100644 --- a/drivers/staging/android/binder.c +++ b/drivers/staging/android/binder.c @@ -4534,6 +4534,15 @@ 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); |