From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x229.google.com (mail-wm0-x229.google.com [IPv6:2a00:1450:400c:c09::229]) (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 B077F1A0405 for ; Thu, 18 Feb 2016 02:05:03 +1100 (AEDT) Received: by mail-wm0-x229.google.com with SMTP id g62so241291055wme.0 for ; Wed, 17 Feb 2016 07:05:03 -0800 (PST) Date: Wed, 17 Feb 2016 17:04:56 +0200 From: "Kirill A. Shutemov" To: Gerald Schaefer Cc: Sebastian Ott , Andrea Arcangeli , Christian Borntraeger , "Kirill A. Shutemov" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Aneesh Kumar K.V" , Andrew Morton , Linus Torvalds , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev@lists.ozlabs.org, Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, Martin Schwidefsky , Heiko Carstens , linux-s390@vger.kernel.org Subject: Re: [BUG] random kernel crashes after THP rework on s390 (maybe also on PowerPC and ARM) Message-ID: <20160217150456.GA15882@node.shutemov.name> References: <20160211205702.24f0d17a@thinkpad> <20160212154116.GA15142@node.shutemov.name> <56BE00E7.1010303@de.ibm.com> <20160212181640.4eabb85f@thinkpad> <20160212231510.GB15142@node.shutemov.name> <20160215113159.GA28832@node.shutemov.name> <20160215193702.4a15ed5e@thinkpad> <20160215213526.GA9766@node.shutemov.name> <20160216172444.013988d8@thinkpad> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20160216172444.013988d8@thinkpad> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Feb 16, 2016 at 05:24:44PM +0100, Gerald Schaefer wrote: > On Mon, 15 Feb 2016 23:35:26 +0200 > "Kirill A. Shutemov" wrote: > > > Is there any chance that I'll be able to trigger the bug using QEMU? > > Does anybody have an QEMU image I can use? > > > > I have no image, but trying to reproduce this under virtualization may > help to trigger this also on other architectures. After ruling out IPI > vs. fast_gup I do not really see why this should be arch-specific, and > it wouldn't be the first time that we hit subtle races first on s390, due > to our virtualized environment (my test case is make -j20 with 10 CPUs and > 4GB of memory, no swap). Could you post your kernel config? It would be nice also to check if disabling split_huge_page() would make any difference: diff --git a/mm/huge_memory.c b/mm/huge_memory.c index a75081ca31cf..26d2b7b21021 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3364,6 +3364,8 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) bool mlocked; unsigned long flags; + return -EBUSY; + VM_BUG_ON_PAGE(is_huge_zero_page(page), page); VM_BUG_ON_PAGE(!PageAnon(page), page); VM_BUG_ON_PAGE(!PageLocked(page), page); -- Kirill A. Shutemov