From f11fc6e5768dd2a63fa5838213f47603b5f1fa68 Mon Sep 17 00:00:00 2001
From: jmestwa-coder <jmestwa@gmail.com>
Date: Wed, 29 Apr 2026 17:12:35 +0530
Subject: [PATCH] guard against overflow in AllocInst buffer growth

---
 re2/compile.cc | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/re2/compile.cc b/re2/compile.cc
index 95c1b32dd..a1188ec5b 100644
--- a/re2/compile.cc
+++ b/re2/compile.cc
@@ -251,8 +251,13 @@ int Compiler::AllocInst(int n) {
     int cap = inst_.size();
     if (cap == 0)
       cap = 8;
-    while (ninst_ + n > cap)
-      cap *= 2;
+    while (ninst_ + n > cap) {
+      if (cap > max_ninst_ / 2) {
+        cap = max_ninst_;
+      } else {
+        cap *= 2;
+      }
+    }
     PODArray<Prog::Inst> inst(cap);
     if (inst_.data() != NULL)
       memmove(inst.data(), inst_.data(), ninst_*sizeof inst_[0]);