From 31f7aa65f536995c6d933c57230919ae408952a5 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Fri, 24 Dec 2010 14:03:38 -0500 Subject: [PATCH] svcrpc: modifying valid sunrpc cache entries is racy Once a sunrpc cache entry is VALID, we should be replacing it (and allowing any concurrent users to destroy it on last put) instead of trying to update it in place. Otherwise someone referencing the ip_map we're modifying here could try to use the m_client just as we're putting the last reference. The bug should only be seen by users of the legacy nfsd interfaces. (Thanks to Neil for suggestion to use sunrpc_invalidate.) Reviewed-by: NeilBrown Signed-off-by: J. Bruce Fields --- net/sunrpc/svcauth_unix.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c index a04ac9193d5..59a7c524a8b 100644 --- a/net/sunrpc/svcauth_unix.c +++ b/net/sunrpc/svcauth_unix.c @@ -401,8 +401,7 @@ struct auth_domain *auth_unix_lookup(struct net *net, struct in6_addr *addr) return NULL; if ((ipm->m_client->addr_changes - ipm->m_add_change) >0) { - if (test_and_set_bit(CACHE_NEGATIVE, &ipm->h.flags) == 0) - auth_domain_put(&ipm->m_client->h); + sunrpc_invalidate(&ipm->h, sn->ip_map_cache); rv = NULL; } else { rv = &ipm->m_client->h; -- 2.20.1