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=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,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 90C3CC169C4 for ; Sun, 3 Feb 2019 07:50:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 51D772083B for ; Sun, 3 Feb 2019 07:50:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="j1Y56DFt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727330AbfBCHt5 (ORCPT ); Sun, 3 Feb 2019 02:49:57 -0500 Received: from mail-pl1-f196.google.com ([209.85.214.196]:38773 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725891AbfBCHt5 (ORCPT ); Sun, 3 Feb 2019 02:49:57 -0500 Received: by mail-pl1-f196.google.com with SMTP id e5so5356989plb.5 for ; Sat, 02 Feb 2019 23:49:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=yAVGCwR4YHv/p1wmhEDFGFfEYHAHeNLmDj21CMHWU6Q=; b=j1Y56DFt2NGTw05nbH9Ot/jBLN9I4HvEBXpI4jjrNCzm4/SEvmrSYGmb6x8bTvbSZ/ U/JLUjOXltv3TOUdcxq5mAWUBi3DEwN25OQDq64DdFbQkhvQvdr1wLC2319Qs4q5eaC4 vh5d3fZAT6JJmjEMLLYaD4Dh3KWSydeRISIyYK6nia0t6ilmc05vU/gwl8NuFD+k5BL9 E9ZcaL4osTMs5J+citQcyP8HakaTP954MFfphOlPnrB8/2lkugVxcp3Ag8z5oiUjRGmS lxblVNpxch899icoqgA8Hq7mkVy+oT28zulPIB9pAaHyBrK5DxAoOYZrqfr3qHo43JHi Zklw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=yAVGCwR4YHv/p1wmhEDFGFfEYHAHeNLmDj21CMHWU6Q=; b=QoJS7Ywfx+CgUHgIJm1y/iFby13qw6qABwwcwM1hYtn0Vp/4DjOCCvpDQBY7kIEQ1w HKofeWZBlQd8DYjDqmbJ+uc3HzKkSc83JuwHiR29Rew9MO2K2TW8f8yzgetHoMPrfYHF Z/usWuqsej7Lgt7V3St/JXVSJBhO7SLSYssrtNPAxINgfBHkuJ9ZJI+/vZpTK/+peHmk 492KUKqh9jNjniPyaQUwXTs1jIo2q9afoYlM2TxIM6Y01Ip46FqEiqT+UP4ywNBTRAmF eG1plfshzQG6fWPW86qbAHj0Ap3a62meneP/lbloxYReWc2GeY9ge3SmHiHf5EqeuOMF 9eaQ== X-Gm-Message-State: AJcUukdCCGD3cN5W1Ga1Pw1hsaMh1YJLHoK1UUi59G5OHwTPLL5lCg+A EfHFX+b+FhpId1UJ2Mo6xxIS1EkiVJc= X-Google-Smtp-Source: ALg8bN6j72E0NyqThHWcMQxyc0jCNu3+sl+f5WTdCI/pa6bObZbFxwR/QMFNx05Acpz3jNoJWFs4Aw== X-Received: by 2002:a17:902:9691:: with SMTP id n17mr48097381plp.9.1549180195978; Sat, 02 Feb 2019 23:49:55 -0800 (PST) Received: from ghor.localdomain ([2605:e000:110e:4146:e508:6f47:a727:f2ae]) by smtp.gmail.com with ESMTPSA id e2sm10821857pga.92.2019.02.02.23.49.53 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 02 Feb 2019 23:49:55 -0800 (PST) From: Jack Andersen To: linux-kernel@vger.kernel.org Cc: Andrew Morton , "Eric W. Biederman" , Christian Brauner , Thomas Gleixner , Oleg Nesterov , Jack Andersen Subject: [PATCH] signal: always allocate siginfo for SI_TKILL Date: Sat, 2 Feb 2019 21:49:38 -1000 Message-Id: <20190203074939.7261-1-jackoalan@gmail.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The patch titled `signal: Never allocate siginfo for SIGKILL or SIGSTOP` created a regression for users of PTRACE_GETSIGINFO needing to discern signals that were raised via the tgkill syscall. A notable user of this tgkill+ptrace combination is lldb while debugging a multithreaded program. Without the ability to detect a SIGSTOP originating from tgkill, lldb does not have a way to synchronize on a per-thread basis and falls back to SIGSTOP-ing the entire process. This patch allocates the siginfo as it did previously whenever the SI_TKILL code is present. Signed-off-by: Jack Andersen --- kernel/signal.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index 9a32bc2088c9..7a810aefb5df 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1058,9 +1058,11 @@ static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struc result = TRACE_SIGNAL_DELIVERED; /* * Skip useless siginfo allocation for SIGKILL SIGSTOP, - * and kernel threads. + * and kernel threads. SI_TKILL is an exception to allow + * processes to discern signals originating from tgkill. */ - if (sig_kernel_only(sig) || (t->flags & PF_KTHREAD)) + if ((sig_kernel_only(sig) && info->si_code != SI_TKILL) || + (t->flags & PF_KTHREAD)) goto out_set; /* -- 2.20.1