From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 217C0C71155 for ; Tue, 1 Dec 2020 20:49:12 +0000 (UTC) Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 298A020679 for ; Tue, 1 Dec 2020 20:49:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="JJv/jUDU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 298A020679 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvdimm-bounces@lists.01.org Received: from ml01.vlan13.01.org (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 91EB7100EBBA0; Tue, 1 Dec 2020 12:49:10 -0800 (PST) Received-SPF: None (mailfrom) identity=mailfrom; client-ip=2001:8b0:10b:1236::1; helo=casper.infradead.org; envelope-from=willy@infradead.org; receiver= Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id B659C100EC1FC for ; Tue, 1 Dec 2020 12:49:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=dyBlRLPwKTQ0rIK/KfQyG6Ob+vSn1EgfGLIeGxV2yms=; b=JJv/jUDUAQHzh744cKMjYelWef QTIfn+k/elN1QSMiCosaURKxQ2fWjh8q5u2jiv6QfFKVvUpCoopn/ASQfT2etb0mpcaFppKzMYJXm Go2y9Rwev3yIt6lHEo1tzZH2Wx2Q6u9PRMkr63pL1mC/IMEd1XbOi4IkeJ+0HK/hwir/XDFgjgrEN cdhpbGfdToA0xP9TZ7gkSGag0nCbiIVH+0pdZciOchpvAvCRGfkDtBJxnzM40g2ajgf/GCFJ2W11C YBwt2vpgu5H8EUX4Boxoe/hCjSfDn7VgdY9T2yM55nPU61QYzgqXbURWXBFMxxDDvUGPOpG8UlTrn 97JljK1A==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kkCa4-0002i8-S3; Tue, 01 Dec 2020 20:49:00 +0000 Date: Tue, 1 Dec 2020 20:49:00 +0000 From: Matthew Wilcox To: Dan Williams Subject: Re: mapcount corruption regression Message-ID: <20201201204900.GC11935@casper.infradead.org> References: <20201201022412.GG4327@casper.infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Message-ID-Hash: DRUDYA4GYMM4FZYZOZAO2QMVKYSJV6P7 X-Message-ID-Hash: DRUDYA4GYMM4FZYZOZAO2QMVKYSJV6P7 X-MailFrom: willy@infradead.org X-Mailman-Rule-Hits: nonmember-moderation X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation CC: "Shutemov, Kirill" , Linux Kernel Mailing List , Linux MM , linux-nvdimm , Vlastimil Babka X-Mailman-Version: 3.1.1 Precedence: list List-Id: "Linux-nvdimm developer list." Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Tue, Dec 01, 2020 at 12:42:39PM -0800, Dan Williams wrote: > On Mon, Nov 30, 2020 at 6:24 PM Matthew Wilcox wrote: > > > > On Mon, Nov 30, 2020 at 05:20:25PM -0800, Dan Williams wrote: > > > Kirill, Willy, compound page experts, > > > > > > I am seeking some debug ideas about the following splat: > > > > > > BUG: Bad page state in process lt-pmem-ns pfn:121a12 > > > page:0000000051ef73f7 refcount:0 mapcount:-1024 > > > mapping:0000000000000000 index:0x0 pfn:0x121a12 > > > > Mapcount of -1024 is the signature of: > > > > #define PG_guard 0x00000400 > > Oh, thanks for that. I overlooked how mapcount is overloaded. Although > in v5.10-rc4 that value is: > > #define PG_table 0x00000400 Ah, I was looking at -next, where Roman renumbered it. I know UML had a problem where it was not clearing PG_table, but you seem to be running on bare metal. SuperH did too, but again, you're not using SuperH. > > > > (the bits are inverted, so this turns into 0xfffffbff which is reported > > as -1024) > > > > I assume you have debug_pagealloc enabled? > > Added it, but no extra spew. I'll dig a bit more on how PG_table is > not being cleared in this case. I only asked about debug_pagealloc because that sets PG_guard. Since the problem is actually PG_table, it's not relevant. _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org