From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Mon, 22 Feb 2021 16:26:14 +0000 (+0100)
Subject: rec: Don't delete aggressive cache entries while they are locked
X-Git-Tag: dnsdist-1.6.0-alpha2~12^2~12
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6cf8f84ffbb4a6a4f943d36dc0160a7de09e3deb;p=thirdparty%2Fpdns.git

rec: Don't delete aggressive cache entries while they are locked
---

diff --git a/pdns/recursordist/aggressive_nsec.cc b/pdns/recursordist/aggressive_nsec.cc
index 053dd2c3a9..ca02233248 100644
--- a/pdns/recursordist/aggressive_nsec.cc
+++ b/pdns/recursordist/aggressive_nsec.cc
@@ -101,10 +101,16 @@ void AggressiveNSECCache::removeZoneInfo(const DNSName& zone, bool subzones)
       return;
     }
 
-    std::lock_guard<std::mutex> lock((*got)->d_lock);
-    auto removed = (*got)->d_entries.size();
-    d_zones.remove(zone, false);
-    d_entriesCount -= removed;
+    /* let's increase the ref count of the shared pointer
+       so we get the lock, remove the zone from the tree,
+       then release the lock before the entry is deleted */
+    auto entry = *got;
+    {
+      std::lock_guard<std::mutex> lock(entry->d_lock);
+      auto removed = entry->d_entries.size();
+      d_zones.remove(zone, false);
+      d_entriesCount -= removed;
+    }
   }
 }