From 0b362e320e518f180582138d3c538b6ee549cef1 Mon Sep 17 00:00:00 2001
From: Samuel Moelius <samuel.moelius@trailofbits.com>
Date: Sun, 22 Jun 2025 21:38:20 -0400
Subject: [PATCH] Fix potential deadlock in `CacheState::lock`

---
 src/cargo/util/cache_lock.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/cargo/util/cache_lock.rs b/src/cargo/util/cache_lock.rs
index 7d019d183e6..afd06c998b8 100644
--- a/src/cargo/util/cache_lock.rs
+++ b/src/cargo/util/cache_lock.rs
@@ -408,7 +408,10 @@ impl CacheState {
                     .lock_exclusive(gctx, DOWNLOAD_EXCLUSIVE_DESCR, blocking)
                 {
                     Ok(LockAcquired) => {}
-                    Ok(WouldBlock) => return Ok(WouldBlock),
+                    Ok(WouldBlock) => {
+                        self.mutate_lock.decrement();
+                        return Ok(WouldBlock);
+                    }
                     Err(e) => {
                         self.mutate_lock.decrement();
                         return Err(e);