From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933436AbcAYQMm (ORCPT ); Mon, 25 Jan 2016 11:12:42 -0500 Received: from mout.kundenserver.de ([212.227.126.134]:63194 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757723AbcAYPrX (ORCPT ); Mon, 25 Jan 2016 10:47:23 -0500 From: Arnd Bergmann To: Johannes Weiner , Michal Hocko , Vladimir Davydov Cc: linux-arm-kernel@lists.infradead.org, Arnd Bergmann , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] mm/memcontrol: avoid a spurious gcc warning Date: Mon, 25 Jan 2016 16:45:50 +0100 Message-Id: <1453736756-1959377-3-git-send-email-arnd@arndb.de> X-Mailer: git-send-email 2.7.0 X-Provags-ID: V03:K0:GTS85t4iP6p/bumoMGc9FLQYrHrRpu2Hf8TbowpNnJpjgIxaq7W YvqcE9dVgAVDhcRxgmINPXgl0l//MAPz14PyjkbxhKto9Mlus9pbmyDabZN9Fr9oOZ62B1M M+5rH2byVD7SsesqCY0Oi+oiYjLF/xnsE3wDOdwtNVyGmwELwI71PlczxkwmQ/mLJf0Fpqm cNJP7okKt58j7k7Lz7gig== X-UI-Out-Filterresults: notjunk:1;V01:K0:cl+z2hTPIkg=:EO9II490tvReC1qhro3aEI +Jbi5lWEtcGOshpNW13vxIe2In8eVfbeY0+cDlr8fMF6YmjIKJS7YO8Xh61N4ibPnJGVQ9kCw AQ+Oj9DTO2zglG8FOfGNlRk4xDXTo27f1ythjIUYpymCU7v73P+8KT2fYr/R77SBaYlwmqtQ9 0mvL5HpqKDvfPpR4Xc4iFD95U57nL3B4ie7LbFWJ7X7v6MDF5RxKtAhiZY3Nx9nZlqrZc6XdG PyZKAyGNdiIuo4zE0tcxHrv6S/g6pDsuQX6StLwwmzy1IRTgP1T0/45KEUOtblfB5yrdqv4Vy jBCtoPnoAN/ZwT1un0mYJLBaEn/Cm4YaMxHsVOVHcOjcnu0NCt8zcNnF9lHx8/u/j9T/bSm3q FZyR2Vlc0XOUIyzYV4wSLq9JW95D1x+X8HvoGYD5CEOYoCgzpv/USXoRoeiEiYkS1SrBFf8iD qUhVDG1tOlTOY/kYZnQ2GeyjPuy10ZziGhKbxLXLaubp8U8NXZRHcZw+fw8QoR0CyO1a/578x EeNEUL40Sa2xYuoVAgPh2sP0vX0f7O+3WspX31b9JlMBmHglxpiB75Ts8Otruzi468eBEj+QS 7kGed76xPoDTrfZMku2nvDTQKcqvt31RyAxm91OzveDDV8QzNaBYw/Ej9oW4/9esRIu2XfCZp Jq4ybP+0P7iv5vK9S5hcNJuGsL7IPo2Xg0k0ATwKKWL+ueTSyO0n2D9dmZDA1mi2eSqU= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When CONFIG_DEBUG_VM is set, the various VM_BUG_ON() confuse gcc to the point where it cannot remember that 'memcg' is known to be initialized: mm/memcontrol.c: In function 'mem_cgroup_can_attach': mm/memcontrol.c:4791:9: warning: 'memcg' may be used uninitialized in this function [-Wmaybe-uninitialized] On ARM gcc-5.1, the above happens when any two or more of the VM_BUG_ON() are active, but not when I remove most or all of them. This is clearly random behavior and the only way I've found to shut up the warning is to add an explicit initialization. Signed-off-by: Arnd Bergmann --- mm/memcontrol.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index d06cae2de783..9340eb981653 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4762,6 +4762,7 @@ static int mem_cgroup_can_attach(struct cgroup_taskset *tset) * multiple. */ p = NULL; + memcg = NULL; cgroup_taskset_for_each_leader(leader, css, tset) { WARN_ON_ONCE(p); p = leader; -- 2.7.0