From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AEF17C43334 for ; Mon, 3 Sep 2018 20:45:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6E54020645 for ; Mon, 3 Sep 2018 20:45:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6E54020645 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xmission.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729215AbeIDBHe (ORCPT ); Mon, 3 Sep 2018 21:07:34 -0400 Received: from out03.mta.xmission.com ([166.70.13.233]:50376 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728386AbeIDBHe (ORCPT ); Mon, 3 Sep 2018 21:07:34 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out03.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1fwvjA-00064M-2z; Mon, 03 Sep 2018 14:45:40 -0600 Received: from [105.225.206.69] (helo=x220.Home) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_CBC_SHA256:128) (Exim 4.87) (envelope-from ) id 1fwvj9-0008G7-0H; Mon, 03 Sep 2018 14:45:39 -0600 From: "Eric W. Biederman" To: linux-kernel@vger.kernel.org Cc: Oleg Nesterov , Linus Torvalds , linux-api@vger.kernel.org, "Eric W. Biederman" Date: Mon, 3 Sep 2018 22:44:28 +0200 Message-Id: <20180903204430.25473-8-ebiederm@xmission.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <87musyl3fa.fsf@xmission.com> References: <87musyl3fa.fsf@xmission.com> X-XM-SPF: eid=1fwvj9-0008G7-0H;;;mid=<20180903204430.25473-8-ebiederm@xmission.com>;;;hst=in02.mta.xmission.com;;;ip=105.225.206.69;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1/AwOH91sZnV912KNIa6w1XW/T+j5v8eKk= X-SA-Exim-Connect-IP: 105.225.206.69 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH 08/10] signal: Never allocate siginfo for SIGKILL or SIGSTOP X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The SIGKILL and SIGSTOP signals are never delivered to userspace so queued siginfo for these signals can never be observed. Therefore remove the chance of failure by never even attempting to allocate siginfo in those cases. Signed-off-by: "Eric W. Biederman" --- kernel/signal.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index 20931a892ace..d7d1adf735f4 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1054,10 +1054,11 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, result = TRACE_SIGNAL_DELIVERED; /* - * fast-pathed signals for kernel-internal things like SIGSTOP - * or SIGKILL. + * Skip useless siginfo allocation for SIGKILL SIGSTOP, + * and kernel threads. */ - if ((info == SEND_SIG_FORCED) || (t->flags & PF_KTHREAD)) + if ((info == SEND_SIG_FORCED) || + sig_kernel_only(sig) || (t->flags & PF_KTHREAD)) goto out_set; /* -- 2.17.1