From patchwork Wed Apr 13 08:17:38 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Blanchard X-Patchwork-Id: 609893 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3qlGvc2mLzz9snl for ; Wed, 13 Apr 2016 18:20:28 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=lists.ozlabs.org header.i=@lists.ozlabs.org header.b=mzGKElj9; dkim=fail reason="signature verification failed" (1024-bit key; secure) header.d=samba.org header.i=@samba.org header.b=DBFYyyvD; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 3qlGvc1kdTzDqBg for ; Wed, 13 Apr 2016 18:20:28 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=lists.ozlabs.org; s=201601; t=1460535628; bh=7XrcpC2k7bijGGMTGEGWBs1UxUh7cIxN3W70ODTuiKI=; h=Date:To:Subject:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:Cc:From; b=mzGKElj9+jCZWVjN97ZSZ/pKATyYmqUUmn6gBriKv4YZl/VsQ1rjemHG8299wlfN5 qWqa6UJbt5drxlcGq9UIXKqzaVqkxBY6ecVD9kIQ6wrDwN3iod6JfC1VI4rVltLd0S wSmmfzYUB14lqCwGi1zv+TKV/KB19DlcaxRH0YhI= X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from hr2.samba.org (hr2.samba.org [IPv6:2a01:4f8:192:486::147:1]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3qlGt14pk8zDq5m for ; Wed, 13 Apr 2016 18:19:05 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; secure) header.d=samba.org header.i=@samba.org header.b=DBFYyyvD; dkim-atps=neutral DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=samba.org; s=42627210; h=Message-ID:Cc:To:From:Date; bh=U3CdP6qtCe4GKU7mT8tMjr4jHTEvflUeIgswlX1w5Os=; b=DBFYyyvDzG91PpEPMTyz8uAn3Q2If2qIOd+TtVneYtOomksnuui2qei/HO4wwWl8HFJmzcVpsr8UDLpAdwda2GNQSDGvX7Jl4Y7jE2oY+BPl1WFHGcV+a/zaEzkyBCKnV1qzbP4ExI+Fks5i2TZasTWDquMYGe1aMKM7xgL75Gk=; Received: from [127.0.0.2] (localhost [127.0.0.1]) by hr2.samba.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim) id 1aqG0E-0003NT-GZ; Wed, 13 Apr 2016 08:18:22 +0000 Date: Wed, 13 Apr 2016 18:17:38 +1000 To: Peter Zijlstra , Ingo Molnar , Srikar Dronamraju , tglx@linutronix.de, efault@gmx.de, htejun@gmail.com, tj@kernel.org, torvalds@linux-foundation.org, zhaolei@cn.fujitsu.com, yangds.fnst@cn.fujitsu.com, hpa@zytor.com, Stephen Rothwell , Michael Ellerman Subject: [PATCH] sched/cpuacct: Check for NULL when using task_pt_regs() Message-ID: <20160413181738.5936e98a@kryten> X-Mailer: Claws Mail 3.12.0 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Anton Blanchard via Linuxppc-dev Reply-To: Anton Blanchard Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" task_pt_regs() can return NULL for kernel threads, so add a check. This fixes an oops at boot on ppc64. Fixes: d740037fac70 ("sched/cpuacct: Split usage accounting into user_usage and sys_usage") Signed-off-by: Anton Blanchard Reported-and-Tested-by: Srikar Dronamraju diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c index df947e0..41f85c4 100644 --- a/kernel/sched/cpuacct.c +++ b/kernel/sched/cpuacct.c @@ -316,12 +316,11 @@ static struct cftype files[] = { void cpuacct_charge(struct task_struct *tsk, u64 cputime) { struct cpuacct *ca; - int index; + int index = CPUACCT_USAGE_SYSTEM; + struct pt_regs *regs = task_pt_regs(tsk); - if (user_mode(task_pt_regs(tsk))) + if (regs && user_mode(regs)) index = CPUACCT_USAGE_USER; - else - index = CPUACCT_USAGE_SYSTEM; rcu_read_lock();