From patchwork Mon Jan 24 18:42:50 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 535063 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81F88C433EF for ; Mon, 24 Jan 2022 23:49:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2364793AbiAXXtF (ORCPT ); Mon, 24 Jan 2022 18:49:05 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:52320 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1454274AbiAXVcI (ORCPT ); Mon, 24 Jan 2022 16:32:08 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 22BAD614E1; Mon, 24 Jan 2022 21:32:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2FE14C340E4; Mon, 24 Jan 2022 21:32:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643059926; bh=Qo14H2WFM8vzQOp8leB6E2PM+33J6T1IeUDHX0WOzv0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VrClL7tev6a3jX4b64q/McsUpZGnPC1Aei3ZLC/RMTnSmkJ5o6S0rQyYhyPqXiSah 6pJU3DHwtd0QljLLrNe5VlSNffASFCw0d9n8OhbHjN5QL9Y8NulFEhNQkbIgR7InQN IyjJlWOz38GpYg9HZEi1TuksnYZ+ChiVDo4VaDkc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kees Cook , "Eric W. Biederman" , Sasha Levin Subject: [PATCH 5.16 0781/1039] signal: In get_signal test for signal_group_exit every time through the loop Date: Mon, 24 Jan 2022 19:42:50 +0100 Message-Id: <20220124184151.539020855@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124184125.121143506@linuxfoundation.org> References: <20220124184125.121143506@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eric W. Biederman [ Upstream commit e7f7c99ba911f56bc338845c1cd72954ba591707 ] Recently while investigating a problem with rr and signals I noticed that siglock is dropped in ptrace_signal and get_signal does not jump to relock. Looking farther to see if the problem is anywhere else I see that do_signal_stop also returns if signal_group_exit is true. I believe that test can now never be true, but it is a bit hard to trace through and be certain. Testing signal_group_exit is not expensive, so move the test for signal_group_exit into the for loop inside of get_signal to ensure the test is never skipped improperly. This has been a potential problem since I added the test for signal_group_exit was added. Fixes: 35634ffa1751 ("signal: Always notice exiting tasks") Reviewed-by: Kees Cook Link: https://lkml.kernel.org/r/875yssekcd.fsf_-_@email.froward.int.ebiederm.org Signed-off-by: "Eric W. Biederman" Signed-off-by: Sasha Levin --- kernel/signal.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index dfcee3888b00e..cf97b9c4d665a 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2684,19 +2684,19 @@ relock: goto relock; } - /* Has this task already been marked for death? */ - if (signal_group_exit(signal)) { - ksig->info.si_signo = signr = SIGKILL; - sigdelset(¤t->pending.signal, SIGKILL); - trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO, - &sighand->action[SIGKILL - 1]); - recalc_sigpending(); - goto fatal; - } - for (;;) { struct k_sigaction *ka; + /* Has this task already been marked for death? */ + if (signal_group_exit(signal)) { + ksig->info.si_signo = signr = SIGKILL; + sigdelset(¤t->pending.signal, SIGKILL); + trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO, + &sighand->action[SIGKILL - 1]); + recalc_sigpending(); + goto fatal; + } + if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) && do_signal_stop(0)) goto relock;