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=-5.5 required=3.0 tests=MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 6070ACA9EB9 for ; Mon, 21 Oct 2019 08:26:18 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 210D820640 for ; Mon, 21 Oct 2019 08:26:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 210D820640 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 97CAF6B0003; Mon, 21 Oct 2019 04:26:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 92E156B0005; Mon, 21 Oct 2019 04:26:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 842DD6B0006; Mon, 21 Oct 2019 04:26:17 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0141.hostedemail.com [216.40.44.141]) by kanga.kvack.org (Postfix) with ESMTP id 5AEBB6B0003 for ; Mon, 21 Oct 2019 04:26:17 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id D3CF78249980 for ; Mon, 21 Oct 2019 08:26:16 +0000 (UTC) X-FDA: 76067109552.07.hose49_36c34d97b6455 X-HE-Tag: hose49_36c34d97b6455 X-Filterd-Recvd-Size: 10160 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf18.hostedemail.com (Postfix) with ESMTP for ; Mon, 21 Oct 2019 08:26:16 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id F267BBABB; Mon, 21 Oct 2019 08:26:13 +0000 (UTC) Date: Mon, 21 Oct 2019 10:26:10 +0200 From: Michal Hocko To: linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, alexander.h.duyck@linux.intel.com, aneesh.kumar@linux.ibm.com, anshuman.khandual@arm.com, benh@kernel.crashing.org, borntraeger@de.ibm.com, bp@alien8.de, cai@lca.pw, catalin.marinas@arm.com, christophe.leroy@c-s.fr, dalias@libc.org, damian.tometzki@gmail.com, dan.j.williams@intel.com, dave.hansen@linux.intel.com, david@redhat.com, fenghua.yu@intel.com, gerald.schaefer@de.ibm.com, glider@google.com, gor@linux.ibm.com, gregkh@linuxfoundation.org, heiko.carstens@de.ibm.com, hpa@zytor.com, ira.weiny@intel.com, jgg@ziepe.ca, linux-mm@kvack.org, logang@deltatee.com, luto@kernel.org, mark.rutland@arm.com, mgorman@techsingularity.net, mingo@redhat.com, mm-commits@vger.kernel.org, mpe@ellerman.id.au, osalvador@suse.de, pagupta@redhat.com, pasha.tatashin@soleen.com, pasic@linux.ibm.com, paulus@samba.org, pavel.tatashin@microsoft.com, peterz@infradead.org, richard.weiyang@gmail.com, richardw.yang@linux.intel.com, robin.murphy@arm.com, rppt@linux.ibm.com, stable@vger.kernel.org, steve.capper@arm.com, tglx@linutronix.de, thomas.lendacky@amd.com, tony.luck@intel.com, torvalds@linux-foundation.org, vbabka@suse.cz, will@kernel.org, willy@infradead.org, yamada.masahiro@socionext.com, yaojun8558363@gmail.com, ysato@users.sourceforge.jp, yuzhao@google.com Subject: Re: [patch 07/26] mm/memunmap: don't access uninitialized memmap in memunmap_pages() Message-ID: <20191021082610.GC9379@dhcp22.suse.cz> References: <20191019031939.9XlSnLGcS%akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191019031939.9XlSnLGcS%akpm@linux-foundation.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Has this been properly reviewed? I do not see any Acks nor Reviewed-bys. On Fri 18-10-19 20:19:39, Andrew Morton wrote: > From: "Aneesh Kumar K.V" > Subject: mm/memunmap: don't access uninitialized memmap in memunmap_pages() > > Patch series "mm/memory_hotplug: Shrink zones before removing memory", v6. > > This series fixes the access of uninitialized memmaps when shrinking > zones/nodes and when removing memory. Also, it contains all fixes for > crashes that can be triggered when removing certain namespace using > memunmap_pages() - ZONE_DEVICE, reported by Aneesh. > > We stop trying to shrink ZONE_DEVICE, as it's buggy, fixing it would be > more involved (we don't have SECTION_IS_ONLINE as an indicator), and > shrinking is only of limited use (set_zone_contiguous() cannot detect the > ZONE_DEVICE as contiguous). > > We continue shrinking !ZONE_DEVICE zones, however, I reduced the amount of > code to a minimum. Shrinking is especially necessary to keep > zone->contiguous set where possible, especially, on memory unplug of DIMMs > at zone boundaries. > > -------------------------------------------------------------------------- > > Zones are now properly shrunk when offlining memory blocks or when > onlining failed. This allows to properly shrink zones on memory unplug > even if the separate memory blocks of a DIMM were onlined to different > zones or re-onlined to a different zone after offlining. > > Example: > > :/# cat /proc/zoneinfo > Node 1, zone Movable > spanned 0 > present 0 > managed 0 > :/# echo "online_movable" > /sys/devices/system/memory/memory41/state > :/# echo "online_movable" > /sys/devices/system/memory/memory43/state > :/# cat /proc/zoneinfo > Node 1, zone Movable > spanned 98304 > present 65536 > managed 65536 > :/# echo 0 > /sys/devices/system/memory/memory43/online > :/# cat /proc/zoneinfo > Node 1, zone Movable > spanned 32768 > present 32768 > managed 32768 > :/# echo 0 > /sys/devices/system/memory/memory41/online > :/# cat /proc/zoneinfo > Node 1, zone Movable > spanned 0 > present 0 > managed 0 > > > This patch (of 10): > > With an altmap, the memmap falling into the reserved altmap space are not > initialized and, therefore, contain a garbage NID and a garbage zone. > Make sure to read the NID/zone from a memmap that was initialized. > > This fixes a kernel crash that is observed when destroying a namespace: > > [ 81.356173] kernel BUG at include/linux/mm.h:1107! > cpu 0x1: Vector: 700 (Program Check) at [c000000274087890] > pc: c0000000004b9728: memunmap_pages+0x238/0x340 > lr: c0000000004b9724: memunmap_pages+0x234/0x340 > ... > pid = 3669, comm = ndctl > kernel BUG at include/linux/mm.h:1107! > [c000000274087ba0] c0000000009e3500 devm_action_release+0x30/0x50 > [c000000274087bc0] c0000000009e4758 release_nodes+0x268/0x2d0 > [c000000274087c30] c0000000009dd144 device_release_driver_internal+0x174/0x240 > [c000000274087c70] c0000000009d9dfc unbind_store+0x13c/0x190 > [c000000274087cb0] c0000000009d8a24 drv_attr_store+0x44/0x60 > [c000000274087cd0] c0000000005a7470 sysfs_kf_write+0x70/0xa0 > [c000000274087d10] c0000000005a5cac kernfs_fop_write+0x1ac/0x290 > [c000000274087d60] c0000000004be45c __vfs_write+0x3c/0x70 > [c000000274087d80] c0000000004c26e4 vfs_write+0xe4/0x200 > [c000000274087dd0] c0000000004c2a6c ksys_write+0x7c/0x140 > [c000000274087e20] c00000000000bbd0 system_call+0x5c/0x68 > > The "page_zone(pfn_to_page(pfn)" was introduced by 69324b8f4833 ("mm, > devm_memremap_pages: add MEMORY_DEVICE_PRIVATE support"), however, I > think we will never have driver reserved memory with > MEMORY_DEVICE_PRIVATE (no altmap AFAIKS). > > [david@redhat.com: minimze code changes, rephrase description] > Link: http://lkml.kernel.org/r/20191006085646.5768-2-david@redhat.com > Fixes: 2c2a5af6fed2 ("mm, memory_hotplug: add nid parameter to arch_remove_memory") > Signed-off-by: Aneesh Kumar K.V > Signed-off-by: David Hildenbrand > Cc: Dan Williams > Cc: Jason Gunthorpe > Cc: Logan Gunthorpe > Cc: Ira Weiny > Cc: Damian Tometzki > Cc: Alexander Duyck > Cc: Alexander Potapenko > Cc: Andy Lutomirski > Cc: Anshuman Khandual > Cc: Benjamin Herrenschmidt > Cc: Borislav Petkov > Cc: Catalin Marinas > Cc: Christian Borntraeger > Cc: Christophe Leroy > Cc: Dave Hansen > Cc: Fenghua Yu > Cc: Gerald Schaefer > Cc: Greg Kroah-Hartman > Cc: Halil Pasic > Cc: Heiko Carstens > Cc: "H. Peter Anvin" > Cc: Ingo Molnar > Cc: Jun Yao > Cc: Mark Rutland > Cc: Masahiro Yamada > Cc: "Matthew Wilcox (Oracle)" > Cc: Mel Gorman > Cc: Michael Ellerman > Cc: Michal Hocko > Cc: Mike Rapoport > Cc: Oscar Salvador > Cc: Pankaj Gupta > Cc: Paul Mackerras > Cc: Pavel Tatashin > Cc: Pavel Tatashin > Cc: Peter Zijlstra > Cc: Qian Cai > Cc: Rich Felker > Cc: Robin Murphy > Cc: Steve Capper > Cc: Thomas Gleixner > Cc: Tom Lendacky > Cc: Tony Luck > Cc: Vasily Gorbik > Cc: Vlastimil Babka > Cc: Wei Yang > Cc: Wei Yang > Cc: Will Deacon > Cc: Yoshinori Sato > Cc: Yu Zhao > Cc: [5.0+] > Signed-off-by: Andrew Morton > --- > > mm/memremap.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > --- a/mm/memremap.c~mm-memunmap-dont-access-uninitialized-memmap-in-memunmap_pages > +++ a/mm/memremap.c > @@ -103,6 +103,7 @@ static void dev_pagemap_cleanup(struct d > void memunmap_pages(struct dev_pagemap *pgmap) > { > struct resource *res = &pgmap->res; > + struct page *first_page; > unsigned long pfn; > int nid; > > @@ -111,14 +112,16 @@ void memunmap_pages(struct dev_pagemap * > put_page(pfn_to_page(pfn)); > dev_pagemap_cleanup(pgmap); > > + /* make sure to access a memmap that was actually initialized */ > + first_page = pfn_to_page(pfn_first(pgmap)); > + > /* pages are dead and unused, undo the arch mapping */ > - nid = page_to_nid(pfn_to_page(PHYS_PFN(res->start))); > + nid = page_to_nid(first_page); > > mem_hotplug_begin(); > if (pgmap->type == MEMORY_DEVICE_PRIVATE) { > - pfn = PHYS_PFN(res->start); > - __remove_pages(page_zone(pfn_to_page(pfn)), pfn, > - PHYS_PFN(resource_size(res)), NULL); > + __remove_pages(page_zone(first_page), PHYS_PFN(res->start), > + PHYS_PFN(resource_size(res)), NULL); > } else { > arch_remove_memory(nid, res->start, resource_size(res), > pgmap_altmap(pgmap)); > _ -- Michal Hocko SUSE Labs