From a9ed3aa9b87ee41e8ab3ff471b1331c154767e45 Mon Sep 17 00:00:00 2001
From: Dave Airlie <airlied@redhat.com>
Date: Sat, 26 Sep 2026 07:57:59 +1000
Subject: Merge tag 'drm-misc-fixes-2026-09-24' of
 https://gitlab.freedesktop.org/drm/misc/kernel into drm-fixes

A number of fixes:
  - bridge:
    - samsung-dsim: fix GPIO lifetime
  - client: Null pointer dereference fix
  - imagination: error handling fix, page handling fix
  - nouveau: fix reference leaks, double-frees, out-of-bounds accesses,
    use-after-frees, don't reject config without SCDC,  a number of
    workarounds
  - virtio: fix memory leak, reference leaks, null pointer dereference,
    add pixel blend mode, cache coherency fix

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Maxime Ripard <self@mripard.dev>
Link: https://patch.msgid.link/arU22zzqUGDEco1y@houat
---
 rust/syn/thread.rs | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 rust/syn/thread.rs

(limited to 'rust/syn/thread.rs')

diff --git a/rust/syn/thread.rs b/rust/syn/thread.rs
new file mode 100644
index 000000000..4165a173d
--- /dev/null
+++ b/rust/syn/thread.rs
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+use std::fmt::{self, Debug};
+use std::thread::{self, ThreadId};
+
+/// ThreadBound is a Sync-maker and Send-maker that allows accessing a value
+/// of type T only from the original thread on which the ThreadBound was
+/// constructed.
+pub(crate) struct ThreadBound<T> {
+    value: T,
+    thread_id: ThreadId,
+}
+
+unsafe impl<T> Sync for ThreadBound<T> {}
+
+// Send bound requires Copy, as otherwise Drop could run in the wrong place.
+//
+// Today Copy and Drop are mutually exclusive so `T: Copy` implies `T: !Drop`.
+// This impl needs to be revisited if that restriction is relaxed in the future.
+unsafe impl<T: Copy> Send for ThreadBound<T> {}
+
+impl<T> ThreadBound<T> {
+    pub(crate) fn new(value: T) -> Self {
+        ThreadBound {
+            value,
+            thread_id: thread::current().id(),
+        }
+    }
+
+    pub(crate) fn get(&self) -> Option<&T> {
+        if thread::current().id() == self.thread_id {
+            Some(&self.value)
+        } else {
+            None
+        }
+    }
+}
+
+impl<T: Debug> Debug for ThreadBound<T> {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        match self.get() {
+            Some(value) => Debug::fmt(value, formatter),
+            None => formatter.write_str("unknown"),
+        }
+    }
+}
+
+// Copy the bytes of T, even if the currently running thread is the "wrong"
+// thread. This is fine as long as the original thread is not simultaneously
+// mutating this value via interior mutability, which would be a data race.
+//
+// Currently `T: Copy` is sufficient to guarantee that T contains no interior
+// mutability, because _all_ interior mutability in Rust is built on
+// std::cell::UnsafeCell, which has no Copy impl. This impl needs to be
+// revisited if that restriction is relaxed in the future.
+impl<T: Copy> Copy for ThreadBound<T> {}
+
+impl<T: Copy> Clone for ThreadBound<T> {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
-- 
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