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=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 2DAC1C35242 for ; Sat, 8 Feb 2020 18:30:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 12E2421775 for ; Sat, 8 Feb 2020 18:30:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728207AbgBHSae (ORCPT ); Sat, 8 Feb 2020 13:30:34 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:34556 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727937AbgBHS3s (ORCPT ); Sat, 8 Feb 2020 13:29:48 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1j0UrN-0003hn-Tc; Sat, 08 Feb 2020 18:29:42 +0000 Received: from ben by deadeye with local (Exim 4.93) (envelope-from ) id 1j0UrN-000CXr-GC; Sat, 08 Feb 2020 18:29:41 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Christian Borntraeger" , "Heiko Carstens" , "Vasily Gorbik" Date: Sat, 08 Feb 2020 18:21:27 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 148/148] s390: Fix unmatched preempt_disable() on exit In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.82-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Ben Hutchings exit_thread_runtime_instr() may return with preemption disabled, leading to the following lockdep splat: BUG: sleeping function called from invalid context at kernel/locking/mutex.c:586 in_atomic(): 1, irqs_disabled(): 0, pid: 565, name: kworker/u2:0 no locks held by kworker/u2:0/565. CPU: 0 PID: 565 Comm: kworker/u2:0 Not tainted 3.16.81-00145-gafe1c874fa44 #1 00000000025dbbd8 00000000025dbbe8 0000000000000002 0000000000000000 00000000025dbc78 00000000025dbbf0 00000000025dbbf0 000000000098c55c 0000000000000000 00000000025d05b8 00000000025d1590 0000000000000000 0000000000000000 000000000000000c 00000000025dbbd8 0000000000000070 00000000009b7220 000000000098c55c 00000000025dbbd8 00000000025dbc20 Call Trace: ([<000000000098c4ce>] show_trace+0xb6/0xd8) [<000000000098c592>] show_stack+0xa2/0xd8 [<0000000000992c04>] dump_stack+0xc4/0x118 [<0000000000191e20>] __might_sleep+0x230/0x238 [<000000000099fbb0>] mutex_lock_nested+0x48/0x3d8 [<000000000025e33e>] perf_event_exit_task+0x36/0x398 [<0000000000158536>] do_exit+0x3ae/0xca0 [<0000000000175826>] ____call_usermodehelper+0x136/0x148 [<00000000009a550a>] kernel_thread_starter+0x6/0xc [<00000000009a5504>] kernel_thread_starter+0x0/0xc This was fixed by commit 8d9047f8b967 "s390/runtime instrumentation: simplify task exit handling" upstream, but that won't apply here. Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Signed-off-by: Ben Hutchings --- --- a/arch/s390/kernel/runtime_instr.c +++ b/arch/s390/kernel/runtime_instr.c @@ -53,9 +53,9 @@ void exit_thread_runtime_instr(void) { struct task_struct *task = current; - preempt_disable(); if (!task->thread.ri_cb) return; + preempt_disable(); disable_runtime_instr(); kfree(task->thread.ri_cb); task->thread.ri_signum = 0;