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=-12.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 1308AC10F13 for ; Tue, 16 Apr 2019 10:12:57 +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 D45CE20652 for ; Tue, 16 Apr 2019 10:12:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="oCJ+VBzR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D45CE20652 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com 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:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=RitFcocuVzbuJSK0Wk03jzS2jtrzNM4zGHpx8eJQUJg=; b=oCJ+VBzRTYiSEL 1HblxqvBvCn2WZo1tjIakUgSy6pVjPlUe9YQ10qsJXTWT7AYeV8OSBxxK1G4sCvq6gawIb7fX6G0Z 2+65qusHACH7nwVMjm1FJtY8UyccT+VtXCETcsrtB7/9qV0LrLF9C+Ivc/1r+XHgy5CeIQ86ZoCZ8 4KwMjupdJudYZXSx1mndJLv/wQstNelvFxzuOyseUmirZFn2kLCHn7GijmYOO6K4J5uzF+uTgg7IS AqHbRRXfxlDDCwA07Xi2qrHjbXEOw2JSRueNHHVTlkh8PcjFVGwr2ky7bFvxt4DyTeEhcLL847wIG LsmiyzBJaQC/WpFEmkxA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hGL58-0001LZ-3J; Tue, 16 Apr 2019 10:12:50 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hGL53-0001Ja-S8 for linux-arm-kernel@lists.infradead.org; Tue, 16 Apr 2019 10:12:47 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6A49E80D; Tue, 16 Apr 2019 03:12:45 -0700 (PDT) Received: from [10.162.42.238] (p8cg001049571a15.blr.arm.com [10.162.42.238]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1DE703F68F; Tue, 16 Apr 2019 03:12:38 -0700 (PDT) Subject: Re: [PATCH V2 1/2] mm/hotplug: Reorder arch_remove_memory() call in __remove_memory() To: David Hildenbrand , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, akpm@linux-foundation.org, will.deacon@arm.com, catalin.marinas@arm.com References: <1555221553-18845-1-git-send-email-anshuman.khandual@arm.com> <1555221553-18845-2-git-send-email-anshuman.khandual@arm.com> From: Anshuman Khandual Message-ID: Date: Tue, 16 Apr 2019 15:42:38 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190416_031245_939189_2B1C114E X-CRM114-Status: GOOD ( 21.27 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, mhocko@suse.com, ira.weiny@intel.com, robin.murphy@arm.com, cai@lca.pw, logang@deltatee.com, james.morse@arm.com, cpandya@codeaurora.org, arunks@codeaurora.org, dan.j.williams@intel.com, mgorman@techsingularity.net, osalvador@suse.de 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 04/15/2019 07:28 PM, David Hildenbrand wrote: > On 14.04.19 07:59, Anshuman Khandual wrote: >> Memory hot remove uses get_nid_for_pfn() while tearing down linked sysfs >> entries between memory block and node. It first checks pfn validity with >> pfn_valid_within() before fetching nid. With CONFIG_HOLES_IN_ZONE config >> (arm64 has this enabled) pfn_valid_within() calls pfn_valid(). >> >> pfn_valid() is an arch implementation on arm64 (CONFIG_HAVE_ARCH_PFN_VALID) >> which scans all mapped memblock regions with memblock_is_map_memory(). This >> creates a problem in memory hot remove path which has already removed given >> memory range from memory block with memblock_[remove|free] before arriving >> at unregister_mem_sect_under_nodes(). Hence get_nid_for_pfn() returns -1 >> skipping subsequent sysfs_remove_link() calls leaving node <-> memory block >> sysfs entries as is. Subsequent memory add operation hits BUG_ON() because >> of existing sysfs entries. >> >> [ 62.007176] NUMA: Unknown node for memory at 0x680000000, assuming node 0 >> [ 62.052517] ------------[ cut here ]------------ >> [ 62.053211] kernel BUG at mm/memory_hotplug.c:1143! >> [ 62.053868] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP >> [ 62.054589] Modules linked in: >> [ 62.054999] CPU: 19 PID: 3275 Comm: bash Not tainted 5.1.0-rc2-00004-g28cea40b2683 #41 >> [ 62.056274] Hardware name: linux,dummy-virt (DT) >> [ 62.057166] pstate: 40400005 (nZcv daif +PAN -UAO) >> [ 62.058083] pc : add_memory_resource+0x1cc/0x1d8 >> [ 62.058961] lr : add_memory_resource+0x10c/0x1d8 >> [ 62.059842] sp : ffff0000168b3ce0 >> [ 62.060477] x29: ffff0000168b3ce0 x28: ffff8005db546c00 >> [ 62.061501] x27: 0000000000000000 x26: 0000000000000000 >> [ 62.062509] x25: ffff0000111ef000 x24: ffff0000111ef5d0 >> [ 62.063520] x23: 0000000000000000 x22: 00000006bfffffff >> [ 62.064540] x21: 00000000ffffffef x20: 00000000006c0000 >> [ 62.065558] x19: 0000000000680000 x18: 0000000000000024 >> [ 62.066566] x17: 0000000000000000 x16: 0000000000000000 >> [ 62.067579] x15: ffffffffffffffff x14: ffff8005e412e890 >> [ 62.068588] x13: ffff8005d6b105d8 x12: 0000000000000000 >> [ 62.069610] x11: ffff8005d6b10490 x10: 0000000000000040 >> [ 62.070615] x9 : ffff8005e412e898 x8 : ffff8005e412e890 >> [ 62.071631] x7 : ffff8005d6b105d8 x6 : ffff8005db546c00 >> [ 62.072640] x5 : 0000000000000001 x4 : 0000000000000002 >> [ 62.073654] x3 : ffff8005d7049480 x2 : 0000000000000002 >> [ 62.074666] x1 : 0000000000000003 x0 : 00000000ffffffef >> [ 62.075685] Process bash (pid: 3275, stack limit = 0x00000000d754280f) >> [ 62.076930] Call trace: >> [ 62.077411] add_memory_resource+0x1cc/0x1d8 >> [ 62.078227] __add_memory+0x70/0xa8 >> [ 62.078901] probe_store+0xa4/0xc8 >> [ 62.079561] dev_attr_store+0x18/0x28 >> [ 62.080270] sysfs_kf_write+0x40/0x58 >> [ 62.080992] kernfs_fop_write+0xcc/0x1d8 >> [ 62.081744] __vfs_write+0x18/0x40 >> [ 62.082400] vfs_write+0xa4/0x1b0 >> [ 62.083037] ksys_write+0x5c/0xc0 >> [ 62.083681] __arm64_sys_write+0x18/0x20 >> [ 62.084432] el0_svc_handler+0x88/0x100 >> [ 62.085177] el0_svc+0x8/0xc >> >> Re-ordering arch_remove_memory() with memblock_[free|remove] solves the >> problem on arm64 as pfn_valid() behaves correctly and returns positive >> as memblock for the address range still exists. arch_remove_memory() >> removes applicable memory sections from zone with __remove_pages() and >> tears down kernel linear mapping. Removing memblock regions afterwards >> is safe because there is no other memblock (bootmem) allocator user that >> late. So nobody is going to allocate from the removed range just to blow >> up later. Also nobody should be using the bootmem allocated range else >> we wouldn't allow to remove it. So reordering is indeed safe. >> >> Acked-by: Michal Hocko >> Reviewed-by: David Hildenbrand >> Reviewed-by: Oscar Salvador >> Signed-off-by: Anshuman Khandual >> --- >> mm/memory_hotplug.c | 3 +-- >> 1 file changed, 1 insertion(+), 2 deletions(-) >> >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >> index 0082d69..71d0d79 100644 >> --- a/mm/memory_hotplug.c >> +++ b/mm/memory_hotplug.c >> @@ -1872,11 +1872,10 @@ void __ref __remove_memory(int nid, u64 start, u64 size) >> >> /* remove memmap entry */ >> firmware_map_remove(start, start + size, "System RAM"); >> + arch_remove_memory(nid, start, size, NULL); >> memblock_free(start, size); >> memblock_remove(start, size); >> >> - arch_remove_memory(nid, start, size, NULL); >> - >> try_offline_node(nid); >> >> mem_hotplug_done(); >> > > This will conflict with a patch I posted, but should be easy > to fix. We should stick to the reverse order in which things are added, > which is what you are doing here. > > commit 5af92d15e179557143d54bde477f7e45fc5c0fca > Author: David Hildenbrand > Date: Wed Apr 10 11:02:26 2019 +1000 > > mm/memory_hotplug: release memory resource after arch_remove_memory() > Got it. My current WIP branch is on the following. We should be able to fix it during merge. git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel