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| author | Martijn Coenen <maco@android.com> | 2018-02-16 09:47:15 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-02-16 11:16:38 +0100 |
| commit | 5eeb2ca02a2f6084fc57ae5c244a38baab07033a (patch) | |
| tree | 86ee4c41c581810a860fc963293da1bed7724798 /drivers/android | |
| parent | 8ca86f1639ec5890d400fff9211aca22d0a392eb (diff) | |
| download | linux-5eeb2ca02a2f6084fc57ae5c244a38baab07033a.tar.gz linux-5eeb2ca02a2f6084fc57ae5c244a38baab07033a.tar.bz2 linux-5eeb2ca02a2f6084fc57ae5c244a38baab07033a.zip | |
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>
Diffstat (limited to 'drivers/android')
| -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 a85f9033b57e..764b63a5aade 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -4382,6 +4382,15 @@ 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); |