From: Benoît Ganne <bganne@cisco.com>
Date: Wed, 25 Jun 2025 14:39:54 +0000 (+0200)
Subject: dns: fix recursive locking
X-Git-Tag: v26.02-rc0~209
X-Git-Url: https://gerrit.fd.io/r/gitweb?a=commitdiff_plain;h=87557a38778f4d87c44b476efb896337dd8241e7;p=vpp.git

dns: fix recursive locking

All callers to delete_random_entry() are already holding the lock to
the DNS cache. Thanks to Rain for the report.

Type: fix

Change-Id: Id051427016f9b7444b812019ccc0f5085fd3e469
Signed-off-by: Benoît Ganne <bganne@cisco.com>
---

diff --git a/src/plugins/dns/dns.c b/src/plugins/dns/dns.c
index de01474703b..b73d18a7416 100644
--- a/src/plugins/dns/dns.c
+++ b/src/plugins/dns/dns.c
@@ -654,7 +654,8 @@ delete_random_entry (dns_main_t * dm)
     return VNET_API_ERROR_UNSPECIFIED;
 #endif
 
-  dns_cache_lock (dm, 3);
+  CLIB_SPINLOCK_ASSERT_LOCKED (&dm->cache_lock);
+
   limit = pool_elts (dm->entries);
   start_index = random_u32 (&dm->random_seed) % limit;
 
@@ -670,12 +671,10 @@ delete_random_entry (dns_main_t * dm)
 	      && ((ep->flags & DNS_CACHE_ENTRY_FLAG_STATIC) == 0))
 	    {
 	      rv = vnet_dns_delete_entry_by_index_nolock (dm, victim_index);
-	      dns_cache_unlock (dm);
 	      return rv;
 	    }
 	}
     }
-  dns_cache_unlock (dm);
 
   clib_warning ("Couldn't find an entry to delete?");
   return VNET_API_ERROR_UNSPECIFIED;