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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 CF7F7C432C0 for ; Tue, 19 Nov 2019 20:44:12 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 A5E202243E for ; Tue, 19 Nov 2019 20:44:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Xi+T/1d0"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="F7dezTir" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A5E202243E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Mime-Version:References:In-Reply-To: Message-Id:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=qtjwQgRoZ4Gg/PVHtcvkaHyVjbWfK6JEe0F/p4gkDCA=; b=Xi+T/1d06U9PBJ cInFVTurq/j8MIh8MD2JdXAY1/6PFr/rbz5lR8NBTomiSfqjUI5YvkqG0480veAstSNMkW03+ifQP KKJlg06qIUKi/9wdg96vjg+xHLKr34pEwdY2THDVH+/DXUL8OCppLOSBRVmBS3ajbEQlRpUKKqKvk YPmRvm0opY6QwbYbC/z0dU8CJFGBHI5xx03YuyHHv460l3oAO1moTyqvUyNS3Rg0CjHBaav9p4yQl XxPXo458rfvFDF4j8ln/rkX+/Qd2a3ymIVuQpbjVrZwdWtyR3G+M0cLM7suY0Mc8PTZqZ1rmeSjdq pu4HFciuA16on/a+DMqA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iXAM6-00045e-Qi; Tue, 19 Nov 2019 20:44:10 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iXAM3-000450-U0 for linux-arm-kernel@lists.infradead.org; Tue, 19 Nov 2019 20:44:09 +0000 Received: from akpm3.svl.corp.google.com (unknown [104.133.8.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5D13B2068F; Tue, 19 Nov 2019 20:44:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574196246; bh=tYk3NzkyGFMwfIfw621e64JBWLZbc2P157zpqSHKBfU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=F7dezTirkHNZxF7r6iTVPjtQ2Gbnu/LKU0RXnzga76cLNAMs/2QcxVsC33X8jJNzH oI7UYI/oLaywEAbINKt2ngiHBiK1DoXioL9Ijnjil8D+Sp/npeg+W2IAQV+IJ+AhP6 ci4IOmZuWXhLBr5x71GSi1Uw1czpCbFrPEBd3sr8= Date: Tue, 19 Nov 2019 12:44:05 -0800 From: Andrew Morton To: David Hildenbrand Subject: Re: [PATCH v6 04/10] mm/memory_hotplug: Don't access uninitialized memmaps in shrink_zone_span() Message-Id: <20191119124405.60a1f92f8e1cffed1afa0442@linux-foundation.org> In-Reply-To: <8bbbd4f1-e2c9-b654-ab73-aa4314135f21@redhat.com> References: <20191006085646.5768-1-david@redhat.com> <20191006085646.5768-5-david@redhat.com> <5a4573de-bd8a-6cd3-55d0-86d503a236fd@redhat.com> <20191014121719.cb9b9efe51a7e9e985b38075@linux-foundation.org> <8bbbd4f1-e2c9-b654-ab73-aa4314135f21@redhat.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191119_124408_008283_AAC922E3 X-CRM114-Status: GOOD ( 16.52 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-s390@vger.kernel.org, Michal Hocko , linux-ia64@vger.kernel.org, Pavel Tatashin , linux-sh@vger.kernel.org, "Aneesh Kumar K . V" , x86@kernel.org, linux-kernel@vger.kernel.org, Alexander Duyck , linux-mm@kvack.org, Dan Williams , linuxppc-dev@lists.ozlabs.org, Toshiki Fukasawa , linux-arm-kernel@lists.infradead.org, Oscar Salvador Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, 19 Nov 2019 15:16:22 +0100 David Hildenbrand wrote: > On 14.10.19 21:17, Andrew Morton wrote: > > On Mon, 14 Oct 2019 11:32:13 +0200 David Hildenbrand wrote: > > > >>> Fixes: d0dc12e86b31 ("mm/memory_hotplug: optimize memory hotplug") > >> > >> @Andrew, can you convert that to > >> > >> Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded > >> memory to zones until online") # visible after d0dc12e86b319 > >> > >> and add > >> > >> Cc: stable@vger.kernel.org # v4.13+ > > > > Done, thanks. > > > > Just a note that Toshiki reported a BUG (race between delayed > initialization of ZONE_DEVICE memmaps without holding the memory > hotplug lock and concurrent zone shrinking). > > https://lkml.org/lkml/2019/11/14/1040 > > "Iteration of create and destroy namespace causes the panic as below: > > [ 41.207694] kernel BUG at mm/page_alloc.c:535! > [ 41.208109] invalid opcode: 0000 [#1] SMP PTI > [ 41.208508] CPU: 7 PID: 2766 Comm: ndctl Not tainted 5.4.0-rc4 #6 > [ 41.209064] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.0-0-g63451fca13-prebuilt.qemu-project.org 04/01/2014 > [ 41.210175] RIP: 0010:set_pfnblock_flags_mask+0x95/0xf0 > [ 41.210643] Code: 04 41 83 e2 3c 48 8d 04 a8 48 c1 e0 07 48 03 04 dd e0 59 55 bb 48 8b 58 68 48 39 da 73 0e 48 c7 c6 70 ac 11 bb e8 1b b2 fd ff <0f> 0b 48 03 58 78 48 39 da 73 e9 49 01 ca b9 3f 00 00 00 4f 8d 0c > [ 41.212354] RSP: 0018:ffffac0d41557c80 EFLAGS: 00010246 > [ 41.212821] RAX: 000000000000004a RBX: 0000000000244a00 RCX: 0000000000000000 > [ 41.213459] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffbb1197dc > [ 41.214100] RBP: 000000000000000c R08: 0000000000000439 R09: 0000000000000059 > [ 41.214736] R10: 0000000000000000 R11: ffffac0d41557b08 R12: ffff8be475ea72b0 > [ 41.215376] R13: 000000000000fa00 R14: 0000000000250000 R15: 00000000fffc0bb5 > [ 41.216008] FS: 00007f30862ab600(0000) GS:ffff8be57bc40000(0000) knlGS:0000000000000000 > [ 41.216771] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 41.217299] CR2: 000055e824d0d508 CR3: 0000000231dac000 CR4: 00000000000006e0 > [ 41.217934] Call Trace: > [ 41.218225] memmap_init_zone_device+0x165/0x17c > [ 41.218642] memremap_pages+0x4c1/0x540 > [ 41.218989] devm_memremap_pages+0x1d/0x60 > [ 41.219367] pmem_attach_disk+0x16b/0x600 [nd_pmem] > [ 41.219804] ? devm_nsio_enable+0xb8/0xe0 > [ 41.220172] nvdimm_bus_probe+0x69/0x1c0 > [ 41.220526] really_probe+0x1c2/0x3e0 > [ 41.220856] driver_probe_device+0xb4/0x100 > [ 41.221238] device_driver_attach+0x4f/0x60 > [ 41.221611] bind_store+0xc9/0x110 > [ 41.221919] kernfs_fop_write+0x116/0x190 > [ 41.222326] vfs_write+0xa5/0x1a0 > [ 41.222626] ksys_write+0x59/0xd0 > [ 41.222927] do_syscall_64+0x5b/0x180 > [ 41.223264] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > [ 41.223714] RIP: 0033:0x7f30865d0ed8 > [ 41.224037] Code: 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 45 78 0d 00 8b 00 85 c0 75 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 49 89 d4 55 > [ 41.225920] RSP: 002b:00007fffe5d30a78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 > [ 41.226608] RAX: ffffffffffffffda RBX: 000055e824d07f40 RCX: 00007f30865d0ed8 > [ 41.227242] RDX: 0000000000000007 RSI: 000055e824d07f40 RDI: 0000000000000004 > [ 41.227870] RBP: 0000000000000007 R08: 0000000000000007 R09: 0000000000000006 > [ 41.228753] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004 > [ 41.229419] R13: 00007f30862ab528 R14: 0000000000000001 R15: 000055e824d07f40 > > While creating a namespace and initializing memmap, if you destroy the namespace > and shrink the zone, it will initialize the memmap outside the zone and > trigger VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page) in > set_pfnblock_flags_mask()." > > > This BUG is also mitigated by this commit, where we for now stop to > shrink the ZONE_DEVICE zone until we can do it in a safe and clean > way. > OK, thanks. I updated the changelog, added Reported-by:Toshiki and shall squeeze this fix into 5.4. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel