From 147b0fe6c2e77bef1dca107a89a8b78c4b65e544 Mon Sep 17 00:00:00 2001
From: Daniel Verkamp <dverkamp@chromium.org>
Date: Mon, 11 Nov 2024 14:52:21 -0800
Subject: [PATCH] media: ffmpeg: fix undefined behavior in test_avpacket_drop

The AvBufferSource pointer gets converted into a Rust slice, so it is
not valid to use a null pointer (even though the length is 0). Return a
valid pointer derived from an empty slice instead.

BUG=b:365852007

Change-Id: I12930c98241d2d711826c577ae23944ec8d5d93b
Reviewed-on: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/6013082
Reviewed-by: Alexandre Courbot <acourbot@chromium.org>
Commit-Queue: Daniel Verkamp <dverkamp@chromium.org>
---
 media/ffmpeg/src/avcodec.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/media/ffmpeg/src/avcodec.rs b/media/ffmpeg/src/avcodec.rs
index 14221df624..8cab4db4e3 100644
--- a/media/ffmpeg/src/avcodec.rs
+++ b/media/ffmpeg/src/avcodec.rs
@@ -1041,7 +1041,6 @@ impl Drop for AvFrame {
 
 #[cfg(test)]
 mod tests {
-    use std::ptr;
     use std::sync::atomic::AtomicBool;
     use std::sync::atomic::Ordering;
     use std::sync::Arc;
@@ -1078,7 +1077,7 @@ mod tests {
         }
         impl AvBufferSource for DropTestBufferSource {
             fn as_ptr(&self) -> *const u8 {
-                ptr::null()
+                [].as_ptr()
             }
 
             fn len(&self) -> usize {