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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11D25C4332F for ; Wed, 20 Oct 2021 17:44:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F268E6128E for ; Wed, 20 Oct 2021 17:44:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231166AbhJTRrM (ORCPT ); Wed, 20 Oct 2021 13:47:12 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:43294 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230526AbhJTRrJ (ORCPT ); Wed, 20 Oct 2021 13:47:09 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]:50190) by out01.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1mdFe2-00EwHS-Kv; Wed, 20 Oct 2021 11:44:54 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95]:47894 helo=localhost.localdomain) by in02.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1mdFe1-001NdN-JO; Wed, 20 Oct 2021 11:44:54 -0600 From: "Eric W. Biederman" To: linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, Linus Torvalds , Oleg Nesterov , Al Viro , Kees Cook , "Eric W. Biederman" , Yoshinori Sato , Rich Felker , linux-sh@vger.kernel.org Date: Wed, 20 Oct 2021 12:43:52 -0500 Message-Id: <20211020174406.17889-6-ebiederm@xmission.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <87y26nmwkb.fsf@disp2133> References: <87y26nmwkb.fsf@disp2133> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-XM-SPF: eid=1mdFe1-001NdN-JO;;;mid=<20211020174406.17889-6-ebiederm@xmission.com>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18qGfvNDey5Nh58/KQ3Bf/D8SdnRQ8Fcy0= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH 06/20] signal/sh: Use force_sig(SIGKILL) instead of do_group_exit(SIGKILL) X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org Today the sh code allocates memory the first time a process uses the fpu. If that memory allocation fails, kill the affected task with force_sig(SIGKILL) rather than do_group_exit(SIGKILL). Calling do_group_exit from an exception handler can potentially lead to dead locks as do_group_exit is not designed to be called from interrupt context. Instead use force_sig(SIGKILL) to kill the userspace process. Sending signals in general and force_sig in particular has been tested from interrupt context so there should be no problems. Cc: Yoshinori Sato Cc: Rich Felker Cc: linux-sh@vger.kernel.org Fixes: 0ea820cf9bf5 ("sh: Move over to dynamically allocated FPU context.") Signed-off-by: "Eric W. Biederman" --- arch/sh/kernel/cpu/fpu.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/sh/kernel/cpu/fpu.c b/arch/sh/kernel/cpu/fpu.c index ae354a2931e7..fd6db0ab1928 100644 --- a/arch/sh/kernel/cpu/fpu.c +++ b/arch/sh/kernel/cpu/fpu.c @@ -62,18 +62,20 @@ void fpu_state_restore(struct pt_regs *regs) } if (!tsk_used_math(tsk)) { - local_irq_enable(); + int ret; /* * does a slab alloc which can sleep */ - if (init_fpu(tsk)) { + local_irq_enable(); + ret = init_fpu(tsk); + local_irq_disable(); + if (ret) { /* * ran out of memory! */ - do_group_exit(SIGKILL); + force_sig(SIGKILL); return; } - local_irq_disable(); } grab_fpu(regs); -- 2.20.1