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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 0F722C7618F for ; Mon, 15 Jul 2019 14:46:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CCB54217D9 for ; Mon, 15 Jul 2019 14:46:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563201978; bh=/4Xd/ltewCvcElqBpDR3xalQlIQ4dvr0euhh3ljVm6k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=XkPJsvsZMuFsF0DwIIxAaSHO2UapmRz29LSBI0Bh1SW7pA9wnYAECl6LritMxwzM5 yRRAgwoIC68gM69Uy1fgv1ZLpJ5ad9jTgGFqeMnBaBD6sdkCMYmXlYs0uWzM4sNAt5 /u3oPGFof/VKw0rfr+gNDeIkejbmtCcEymcqaj/s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404953AbfGOOqR (ORCPT ); Mon, 15 Jul 2019 10:46:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:35632 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404643AbfGOOqP (ORCPT ); Mon, 15 Jul 2019 10:46:15 -0400 Received: from sasha-vm.mshome.net (unknown [73.61.17.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 267E2206B8; Mon, 15 Jul 2019 14:46:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563201974; bh=/4Xd/ltewCvcElqBpDR3xalQlIQ4dvr0euhh3ljVm6k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=I+rPwiADKp+R9OdYazCrDl6xYLqd/8DIheTr+cQvSr8yc8a2aM+HHe5Go76BBsZrO HOGs7vNNo2xopFhob0POmKwfREMsC+7vmfSiXrdTgF8ozI+ZuvnqdrLd2N8WAYQDV6 BkIvvRiZZORmeLswspQH6LetGSdYyEMxJgWT/81U= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Eric W. Biederman" , Daniel Lezcano , Serge Hallyn , Oleg Nesterov , Sasha Levin Subject: [PATCH AUTOSEL 4.4 11/53] signal/pid_namespace: Fix reboot_pid_ns to use send_sig not force_sig Date: Mon, 15 Jul 2019 10:44:53 -0400 Message-Id: <20190715144535.11636-11-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190715144535.11636-1-sashal@kernel.org> References: <20190715144535.11636-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Eric W. Biederman" [ Upstream commit f9070dc94542093fd516ae4ccea17ef46a4362c5 ] The locking in force_sig_info is not prepared to deal with a task that exits or execs (as sighand may change). The is not a locking problem in force_sig as force_sig is only built to handle synchronous exceptions. Further the function force_sig_info changes the signal state if the signal is ignored, or blocked or if SIGNAL_UNKILLABLE will prevent the delivery of the signal. The signal SIGKILL can not be ignored and can not be blocked and SIGNAL_UNKILLABLE won't prevent it from being delivered. So using force_sig rather than send_sig for SIGKILL is confusing and pointless. Because it won't impact the sending of the signal and and because using force_sig is wrong, replace force_sig with send_sig. Cc: Daniel Lezcano Cc: Serge Hallyn Cc: Oleg Nesterov Fixes: cf3f89214ef6 ("pidns: add reboot_pid_ns() to handle the reboot syscall") Signed-off-by: "Eric W. Biederman" Signed-off-by: Sasha Levin --- kernel/pid_namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index 567ecc826bc8..6353372801f2 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -325,7 +325,7 @@ int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd) } read_lock(&tasklist_lock); - force_sig(SIGKILL, pid_ns->child_reaper); + send_sig(SIGKILL, pid_ns->child_reaper, 1); read_unlock(&tasklist_lock); do_exit(0); -- 2.20.1