svn commit: r349474 - head/sys/netinet

[John Baldwin]

Author: jhb
Date: Thu Jun 27 22:34:05 2019
New Revision: 349474
URL: https://svnweb.freebsd.org/changeset/base/349474

Log:
  Reject attempts to register a TCP stack being unloaded.
  
  Reviewed by:	gallatin
  MFC after:	2 weeks
  Sponsored by:	Netflix
  Differential Revision:	https://reviews.freebsd.org/D20617

Modified:
  head/sys/netinet/tcp_subr.c

Modified: head/sys/netinet/tcp_subr.c
==============================================================================
--- head/sys/netinet/tcp_subr.c	Thu Jun 27 22:24:56 2019	(r349473)
+++ head/sys/netinet/tcp_subr.c	Thu Jun 27 22:34:05 2019	(r349474)
@@ -798,8 +798,12 @@ register_tcp_functions_as_names(struct tcp_function_bl
 		}
 	}
 
+	if (blk->tfb_flags & TCP_FUNC_BEING_REMOVED) {
+		*num_names = 0;
+		return (EINVAL);
+	}
+
 	refcount_init(&blk->tfb_refcnt, 0);
-	blk->tfb_flags = 0;
 	blk->tfb_id = atomic_fetchadd_int(&next_tcp_stack_id, 1);
 	for (i = 0; i < *num_names; i++) {
 		n = malloc(sizeof(struct tcp_function), M_TCPFUNCTIONS, wait);