From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933865AbcATFqt (ORCPT ); Wed, 20 Jan 2016 00:46:49 -0500 Received: from e23smtp04.au.ibm.com ([202.81.31.146]:59368 "EHLO e23smtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751583AbcATFqm (ORCPT ); Wed, 20 Jan 2016 00:46:42 -0500 X-IBM-Helo: d23dlp02.au.ibm.com X-IBM-MailFrom: aneesh.kumar@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org From: "Aneesh Kumar K.V" To: "Kirill A. Shutemov" , Dmitry Vyukov Cc: "Kirill A. Shutemov" , Sasha Levin , jmarchan@redhat.com, Hugh Dickins , Dave Hansen , David Rientjes , Andrew Morton , Linus Torvalds , Vlastimil Babka , Mel Gorman , Ebru Akagunduz , Dan Williams , Minchan Kim , "linux-mm\@kvack.org" , LKML , syzkaller , Kostya Serebryany , Alexander Potapenko Subject: Re: mm: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected in split_huge_page_to_list In-Reply-To: <20160118133852.GC14531@node.shutemov.name> References: <20160118133852.GC14531@node.shutemov.name> User-Agent: Notmuch/0.20.2 (http://notmuchmail.org) Emacs/24.5.1 (x86_64-pc-linux-gnu) Date: Wed, 20 Jan 2016 11:15:32 +0530 Message-ID: <87powwvm6b.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16012005-0013-0000-0000-000002913661 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org "Kirill A. Shutemov" writes: ...... > > I think this should fix the issue: > > From 10859758dadfa249616870f63c1636ec9857c501 Mon Sep 17 00:00:00 2001 > From: "Kirill A. Shutemov" > Date: Mon, 18 Jan 2016 16:28:12 +0300 > Subject: [PATCH] thp: fix interrupt unsafe locking in split_huge_page() > > split_queue_lock can be taken from interrupt context in some cases, but > I forgot to convert locking in split_huge_page() to interrupt-safe > primitives. > > Let's fix this. Can you add the stack trace from the problem reported to the commit message ?. That will help in identifying the interrupt context call path easily. Reviewed-by: Aneesh Kumar K.V > > Signed-off-by: Kirill A. Shutemov > Reported-by: Dmitry Vyukov > --- > mm/huge_memory.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 50342eff7960..21fda6a10e89 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -3357,6 +3357,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) > struct anon_vma *anon_vma; > int count, mapcount, ret; > bool mlocked; > + unsigned long flags; > > VM_BUG_ON_PAGE(is_huge_zero_page(page), page); > VM_BUG_ON_PAGE(!PageAnon(page), page); > @@ -3396,7 +3397,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) > lru_add_drain(); > > /* Prevent deferred_split_scan() touching ->_count */ > - spin_lock(&split_queue_lock); > + spin_lock_irqsave(&split_queue_lock, flags); > count = page_count(head); > mapcount = total_mapcount(head); > if (!mapcount && count == 1) { > @@ -3404,11 +3405,11 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) > split_queue_len--; > list_del(page_deferred_list(head)); > } > - spin_unlock(&split_queue_lock); > + spin_unlock_irqrestore(&split_queue_lock, flags); > __split_huge_page(page, list); > ret = 0; > } else if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) { > - spin_unlock(&split_queue_lock); > + spin_unlock_irqrestore(&split_queue_lock, flags); > pr_alert("total_mapcount: %u, page_count(): %u\n", > mapcount, count); > if (PageTail(page)) > @@ -3416,7 +3417,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) > dump_page(page, "total_mapcount(head) > 0"); > BUG(); > } else { > - spin_unlock(&split_queue_lock); > + spin_unlock_irqrestore(&split_queue_lock, flags); > unfreeze_page(anon_vma, head); > ret = -EBUSY; > } > -- > Kirill A. Shutemov