Fix race condition in tls half open ctx get/put

Change-Id: I603094215162bfe7d41bbff1b9fe8ab974aa3fab
Signed-off-by: Ping Yu <ping.yu@intel.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/src/vnet/tls/tls.c b/src/vnet/tls/tls.c
index b576c00d4e9..4fb0dfb3c91 100644
--- a/src/vnet/tls/tls.c
+++ b/src/vnet/tls/tls.c
@@ -94,16 +94,17 @@ tls_ctx_half_open_alloc (void)
     {
       clib_rwlock_writer_lock (&tm->half_open_rwlock);
       pool_get (tm->half_open_ctx_pool, ctx);
-      memset (ctx, 0, sizeof (*ctx));
-      ctx_index = ctx - tm->half_open_ctx_pool;
       clib_rwlock_writer_unlock (&tm->half_open_rwlock);
     }
   else
     {
+      /* reader lock assumption: only main thread will call pool_get */
+      clib_rwlock_reader_lock (&tm->half_open_rwlock);
       pool_get (tm->half_open_ctx_pool, ctx);
-      memset (ctx, 0, sizeof (*ctx));
-      ctx_index = ctx - tm->half_open_ctx_pool;
+      clib_rwlock_reader_unlock (&tm->half_open_rwlock);
     }
+  memset (ctx, 0, sizeof (*ctx));
+  ctx_index = ctx - tm->half_open_ctx_pool;
   return ctx_index;
 }