[PATCH 2/3] rust_binder: avoid mem::take on delivered_deaths

[Alice Ryhl <aliceryhl@google.com>]

Similar to the previous commit, List::remove is used on
delivered_deaths, so do not use mem::take on it as that may result in
violations of the List::remove safety requirements.

I don't think this particular case can be triggered because it requires
fd close to run in parallel with an ioctl on the same fd. But let's not
tempt fate.

Cc: stable@vger.kernel.org
Fixes: eafedbc7c050 ("rust_binder: add Rust Binder driver")
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
 drivers/android/binder/process.rs | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/android/binder/process.rs b/drivers/android/binder/process.rs
index f13a747e784c84a0fb09cbf47442712106eba07c..022f554bb049280126fdaf636dc7a41dd02c535e 100644
--- a/drivers/android/binder/process.rs
+++ b/drivers/android/binder/process.rs
@@ -1335,8 +1335,12 @@ fn deferred_release(self: Arc<Self>) {
             work.into_arc().cancel();
         }
 
-        let delivered_deaths = take(&mut self.inner.lock().delivered_deaths);
-        drop(delivered_deaths);
+        // Clear delivered_deaths list.
+        //
+        // Scope ensures that MutexGuard is dropped while executing the body.
+        while let Some(delivered_death) = { self.inner.lock().delivered_deaths.pop_front() } {
+            drop(delivered_death);
+        }
 
         // Free any resources kept alive by allocated buffers.
         let omapping = self.inner.lock().mapping.take();

-- 
2.51.2.1041.gc1ab5b90ca-goog