From ec987c00a25ee9324161843f35e432883d8385e5 Mon Sep 17 00:00:00 2001
From: Rizwan Alam <riscogian@gmail.com>
Date: Thu, 10 Sep 2026 19:20:16 +0530
Subject: [PATCH] Fix overflow in Multi::timeout_i32

---
 src/multi.rs | 29 ++++++++++++++++++++++-------
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/src/multi.rs b/src/multi.rs
index 00fcdcc16..75f1aa10f 100644
--- a/src/multi.rs
+++ b/src/multi.rs
@@ -623,13 +623,8 @@ impl Multi {
     }
 
     fn timeout_i32(timeout: Duration) -> i32 {
-        let secs = timeout.as_secs();
-        if secs > (i32::MAX / 1000) as u64 {
-            // Duration too large, clamp at maximum value.
-            i32::MAX
-        } else {
-            secs as i32 * 1000 + timeout.subsec_nanos() as i32 / 1_000_000
-        }
+        // Duration too large, clamp at maximum value.
+        timeout.as_millis().min(i32::MAX as u128) as i32
     }
 
     /// Block until activity is detected or a timeout passes.
@@ -1352,3 +1347,23 @@ impl fmt::Debug for WaitFd {
             .finish()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::Multi;
+    use std::time::Duration;
+
+    #[test]
+    fn timeout_i32_clamps_at_max() {
+        assert_eq!(Multi::timeout_i32(Duration::from_millis(1500)), 1500);
+        assert_eq!(
+            Multi::timeout_i32(Duration::new(2_147_483, 647_999_999)),
+            i32::MAX
+        );
+        assert_eq!(
+            Multi::timeout_i32(Duration::new(2_147_483, 648_000_000)),
+            i32::MAX
+        );
+        assert_eq!(Multi::timeout_i32(Duration::MAX), i32::MAX);
+    }
+}