Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751983AbaAQJhT (ORCPT ); Fri, 17 Jan 2014 04:37:19 -0500 Received: from mail1.windriver.com ([147.11.146.13]:38163 "EHLO mail1.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750775AbaAQJhP (ORCPT ); Fri, 17 Jan 2014 04:37:15 -0500 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 , , CC: Alexey Lugovskoy Subject: Re: powerpc/hugetlb: BUG: using smp_processor_id() in preemptible References: <201401171323.52657@blacky.localdomain> In-Reply-To: <201401171323.52657@blacky.localdomain> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [128.224.163.134] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 -- 1.7.9.5 Tiejun > > Nikita > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/linuxppc-dev > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/