From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752222AbeDJBQQ (ORCPT ); Mon, 9 Apr 2018 21:16:16 -0400 Received: from mail-pf0-f194.google.com ([209.85.192.194]:43243 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751367AbeDJBQO (ORCPT ); Mon, 9 Apr 2018 21:16:14 -0400 X-Google-Smtp-Source: AIpwx4/jmw4H36S0f1ahLfStt01A6AUavej7daicYAoMH5KIQQDeaPPXv3KyXC066A8tRMysZFTnTw== From: Jia-Ju Bai To: gerrit@erg.abdn.ac.uk, davem@davemloft.net Cc: dccp@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Jia-Ju Bai Subject: [PATCH v2] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create Date: Tue, 10 Apr 2018 09:16:08 +0800 Message-Id: <1523322968-27947-1-git-send-email-baijiaju1990@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org tipc_mon_create() is never called in atomic context. The call chain ending up at dn_route_init() is: [1] tipc_mon_create() <- tipc_enable_bearer() <- tipc_nl_bearer_enable() tipc_nl_bearer_enable() calls rtnl_lock(), which indicates this function is not called in atomic context. Despite never getting called from atomic context, tipc_mon_create() calls kzalloc() with GFP_ATOMIC, which does not sleep for allocation. GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL, which can sleep and improve the possibility of sucessful allocation. This is found by a static analysis tool named DCNS written by myself. And I also manually check it. Signed-off-by: Jia-Ju Bai --- v2: * Modify the description of GFP_ATOMIC in v1. Thank Eric for good advice. --- net/tipc/monitor.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c index 9e109bb..9714d80 100644 --- a/net/tipc/monitor.c +++ b/net/tipc/monitor.c @@ -604,9 +604,9 @@ int tipc_mon_create(struct net *net, int bearer_id) if (tn->monitors[bearer_id]) return 0; - mon = kzalloc(sizeof(*mon), GFP_ATOMIC); - self = kzalloc(sizeof(*self), GFP_ATOMIC); - dom = kzalloc(sizeof(*dom), GFP_ATOMIC); + mon = kzalloc(sizeof(*mon), GFP_KERNEL); + self = kzalloc(sizeof(*self), GFP_KERNEL); + dom = kzalloc(sizeof(*dom), GFP_KERNEL); if (!mon || !self || !dom) { kfree(mon); kfree(self); -- 1.9.1