From patchwork Fri Jan 17 09:35:28 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tiejun Chen X-Patchwork-Id: 311996 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id 01D2C2C00CC for ; Fri, 17 Jan 2014 20:37:18 +1100 (EST) Received: from mail1.windriver.com (mail1.windriver.com [147.11.146.13]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 7EC1B2C007A for ; Fri, 17 Jan 2014 20:36:51 +1100 (EST) Received: from ALA-HCA.corp.ad.wrs.com (ala-hca.corp.ad.wrs.com [147.11.189.40]) by mail1.windriver.com (8.14.5/8.14.5) with ESMTP id s0H9ZXjD013912 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL); Fri, 17 Jan 2014 01:35:34 -0800 (PST) Received: from [128.224.163.134] (128.224.163.134) by ALA-HCA.corp.ad.wrs.com (147.11.189.50) with Microsoft SMTP Server (TLS) id 14.2.347.0; Fri, 17 Jan 2014 01:35:33 -0800 Message-ID: <52D8F960.6030107@windriver.com> Date: Fri, 17 Jan 2014 17:35:28 +0800 From: =?UTF-8?B?IuKAnHRpZWp1bi5jaGVu4oCdIg==?= User-Agent: Mozilla/5.0 (X11; Linux i686; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Nikita Yushchenko , Benjamin Herrenschmidt , Paul Mackerras , "Aneesh Kumar K.V" , Andrew Morton , Naoya Horiguchi , , Subject: Re: powerpc/hugetlb: BUG: using smp_processor_id() in preemptible References: <201401171323.52657@blacky.localdomain> In-Reply-To: <201401171323.52657@blacky.localdomain> X-Originating-IP: [128.224.163.134] Cc: Alexey Lugovskoy X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.16 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 01/17/2014 05:23 PM, Nikita Yushchenko wrote: > Hi > > While running LTP hugeltb tests on freescale powerpc board, I'm getting > > [ 7253.637591] BUG: using smp_processor_id() in preemptible [00000000 00000000] > code: hugemmap01/9048 > [ 7253.637601] caller is free_hugepd_range.constprop.25+0x88/0x1a8 > [ 7253.637605] CPU: 1 PID: 9048 Comm: hugemmap01 Not tainted 3.10.20-rt14+ #114 > [ 7253.637606] Call Trace: > [ 7253.637617] [cb049d80] [c0007ea4] show_stack+0x4c/0x168 (unreliable) > [ 7253.637624] [cb049dc0] [c031c674] debug_smp_processor_id+0x114/0x134 > [ 7253.637628] [cb049de0] [c0016d28] free_hugepd_range.constprop.25+0x88/0x1a8 > [ 7253.637632] [cb049e00] [c001711c] hugetlb_free_pgd_range+0x6c/0x168 > [ 7253.637639] [cb049e40] [c0117408] free_pgtables+0x12c/0x150 > [ 7253.637646] [cb049e70] [c011ce38] unmap_region+0xa0/0x11c > [ 7253.637671] [cb049ef0] [c011f03c] do_munmap+0x224/0x3bc > [ 7253.637676] [cb049f20] [c011f2e0] vm_munmap+0x38/0x5c > [ 7253.637682] [cb049f40] [c000ef88] ret_from_syscall+0x0/0x3c > [ 7253.637686] --- Exception: c01 at 0xff16004 > > This is on 3.10 based kernel but looks like code in question did not change > since then. > > Immediate reason of this dump is usage of smp_processor_id() in hugepd_free(), > which is executed in preemptible context on this path. > > Perhaps need to add preempt_disable() / preempt_enable() somewhere. > But what is the proper location for these? > Could you try this? powerpc/hugetlb: replace __get_cpu_var with get_cpu_var Replace __get_cpu_var safely with get_cpu_var to avoid the following call trace: [ 7253.637591] BUG: using smp_processor_id() in preemptible [00000000 00000000] code: hugemmap01/9048 [ 7253.637601] caller is free_hugepd_range.constprop.25+0x88/0x1a8 [ 7253.637605] CPU: 1 PID: 9048 Comm: hugemmap01 Not tainted 3.10.20-rt14+ #114 [ 7253.637606] Call Trace: [ 7253.637617] [cb049d80] [c0007ea4] show_stack+0x4c/0x168 (unreliable) [ 7253.637624] [cb049dc0] [c031c674] debug_smp_processor_id+0x114/0x134 [ 7253.637628] [cb049de0] [c0016d28] free_hugepd_range.constprop.25+0x88/0x1a8 [ 7253.637632] [cb049e00] [c001711c] hugetlb_free_pgd_range+0x6c/0x168 [ 7253.637639] [cb049e40] [c0117408] free_pgtables+0x12c/0x150 [ 7253.637646] [cb049e70] [c011ce38] unmap_region+0xa0/0x11c [ 7253.637671] [cb049ef0] [c011f03c] do_munmap+0x224/0x3bc [ 7253.637676] [cb049f20] [c011f2e0] vm_munmap+0x38/0x5c [ 7253.637682] [cb049f40] [c000ef88] ret_from_syscall+0x0/0x3c [ 7253.637686] --- Exception: c01 at 0xff16004 Signed-off-by: Tiejun Chen --- arch/powerpc/mm/hugetlbpage.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index fb05b12..42779c0 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -400,12 +400,13 @@ static void hugepd_free(struct mmu_gather *tlb, void *hugepte) { struct hugepd_freelist **batchp; - batchp = &__get_cpu_var(hugepd_freelist_cur); + batchp = &get_cpu_var(hugepd_freelist_cur); if (atomic_read(&tlb->mm->mm_users) < 2 || cpumask_equal(mm_cpumask(tlb->mm), cpumask_of(smp_processor_id()))) { kmem_cache_free(hugepte_cache, hugepte); + put_cpu_var(hugepd_freelist_cur); return; } @@ -419,6 +420,7 @@ static void hugepd_free(struct mmu_gather *tlb, void *hugepte) call_rcu_sched(&(*batchp)->rcu, hugepd_free_rcu_callback); *batchp = NULL; } + put_cpu_var(hugepd_freelist_cur); } #endif