From: J. Bruce Fields Date: Fri, 24 Dec 2010 19:03:38 +0000 (-0500) Subject: svcrpc: modifying valid sunrpc cache entries is racy X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=31f7aa65f536995c6d933c57230919ae408952a5;p=GitHub%2FLineageOS%2Fandroid_kernel_samsung_universal7580.git 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 --- 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;