SERVER-60897 Place upper bound on number of duplicate key retries for updatesr4.2.18-rc0r4.2.18

1 files changed, 8 insertions, 0 deletions

diff --git a/src/mongo/db/ops/write_ops_exec.cpp b/src/mongo/db/ops/write_ops_exec.cpp
index 9e457ebb0e5..5f0096162e4 100644
--- a/src/mongo/db/ops/write_ops_exec.cpp
+++ b/src/mongo/db/ops/write_ops_exec.cpp
@@ -722,6 +722,10 @@ static SingleWriteResult performSingleUpdateOpWithDupKeyRetry(OperationContext*
                                                                : PlanExecutor::YIELD_AUTO);
 
     size_t numAttempts = 0;
+
+    // Upper bound on the number of retries allowed. This prevents the server from getting stuck
+    // in an infinite loop when trying to upsert invalid BSON (see SERVER-60897 for details).
+    constexpr size_t kMaxNumAttempts = 1000;
     while (true) {
         ++numAttempts;
 
@@ -736,6 +740,10 @@ static SingleWriteResult performSingleUpdateOpWithDupKeyRetry(OperationContext*
                 uassertStatusOK(parsedUpdate.parseQueryToCQ());
             }
 
+            if (numAttempts >= kMaxNumAttempts) {
+                throw;
+            }
+
             if (!UpdateStage::shouldRetryDuplicateKeyException(
                     parsedUpdate, *ex.extraInfo<DuplicateKeyErrorInfo>())) {
                 throw;