3 files changed, 12 insertions, 4 deletions
diff --git a/compiler/rustc_query_system/src/query/job.rs b/compiler/rustc_query_system/src/query/job.rs
index 37b305d0a8b..f0cb378f471 100644
--- a/compiler/rustc_query_system/src/query/job.rs
+++ b/compiler/rustc_query_system/src/query/job.rs
@@ -588,7 +588,12 @@ pub fn print_query_stack<Qcx: QueryContext>(
     // state if it was responsible for triggering the panic.
     let mut count_printed = 0;
     let mut count_total = 0;
-    let query_map = qcx.collect_active_jobs();
+
+    // Make use of a partial query map if we fail to take locks collecting active queries.
+    let query_map = match qcx.collect_active_jobs() {
+        Ok(query_map) => query_map,
+        Err(query_map) => query_map,
+    };
 
     if let Some(ref mut file) = file {
         let _ = writeln!(file, "\n\nquery stack during panic:");
diff --git a/compiler/rustc_query_system/src/query/mod.rs b/compiler/rustc_query_system/src/query/mod.rs
index 2ed0c810b75..0d0c66aa978 100644
--- a/compiler/rustc_query_system/src/query/mod.rs
+++ b/compiler/rustc_query_system/src/query/mod.rs
@@ -86,7 +86,7 @@ pub trait QueryContext: HasDepContext {
     /// Get the query information from the TLS context.
     fn current_query_job(self) -> Option<QueryJobId>;
 
-    fn collect_active_jobs(self) -> QueryMap;
+    fn collect_active_jobs(self) -> Result<QueryMap, QueryMap>;
 
     /// Load a side effect associated to the node in the previous session.
     fn load_side_effect(
diff --git a/compiler/rustc_query_system/src/query/plumbing.rs b/compiler/rustc_query_system/src/query/plumbing.rs
index d6b90fbc09f..3a9d80280c2 100644
--- a/compiler/rustc_query_system/src/query/plumbing.rs
+++ b/compiler/rustc_query_system/src/query/plumbing.rs
@@ -260,8 +260,11 @@ where
     Q: QueryConfig<Qcx>,
     Qcx: QueryContext,
 {
-    let error =
-        try_execute.find_cycle_in_stack(qcx.collect_active_jobs(), &qcx.current_query_job(), span);
+    // Ensure there was no errors collecting all active jobs.
+    // We need the complete map to ensure we find a cycle to break.
+    let query_map = qcx.collect_active_jobs().expect("failed to collect active queries");
+
+    let error = try_execute.find_cycle_in_stack(query_map, &qcx.current_query_job(), span);
     (mk_cycle(query, qcx, error), None)
 }