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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 543D6C433E2 for ; Tue, 8 Sep 2020 17:31:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D26A20738 for ; Tue, 8 Sep 2020 17:31:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599586286; bh=Ab6EA6ceLAz7RJxJePWU1hmFTBIR4uJTxutFsHvQBSw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=qvLt/dLFice0Qe8mGJ/dyKkh4IodCJoMJyNZxFxoMMooJvQYFK09gqAcrGsQFT6uD VJHDWjzrWnPYFgyUeeuOS8HgubKlbNavYAcAFX7Kr7zL50e+OYjCcKhjyPX87cIuaD YdqPo8xZ/n/6EFN3CjvCVB1o0Hd498JbPqlKlFrc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728647AbgIHRbX (ORCPT ); Tue, 8 Sep 2020 13:31:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:34570 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731746AbgIHRbC (ORCPT ); Tue, 8 Sep 2020 13:31:02 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 9D61F20738; Tue, 8 Sep 2020 17:31:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599586261; bh=Ab6EA6ceLAz7RJxJePWU1hmFTBIR4uJTxutFsHvQBSw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CW//NNFIH//LBxRHG+UNXHCrX3gxDiebGnZBRTi5MmZfJMd+AkAHnI+aB1pQ3aTeG 2KaiMY8E3N4SFApa9G+6FVQw8Oi1DLIhN5PxBuG475TS1sUXQEmHtiv4JIUvxZatal kv5ZxcyeAdJT/CLFyrino5XTWIcl5ITMrFS0J+Qo= Date: Tue, 8 Sep 2020 19:31:13 +0200 From: Greg Kroah-Hartman To: Laurent Dufour Cc: akpm@linux-foundation.org, david@redhat.com, salvador@suse.de, rafael@kernel.org, nathanl@linux.ibm.com, mhocko@kernel.org, cheloha@linux.ibm.com, stable@vger.kernel.org Subject: Re: [PATCH] mm: don't rely on system state to detect hot-plug operations Message-ID: <20200908173113.GB218801@kroah.com> References: <5cbd92e1-c00a-4253-0119-c872bfa0f2bc@redhat.com> <20200908170835.85440-1-ldufour@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200908170835.85440-1-ldufour@linux.ibm.com> Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Tue, Sep 08, 2020 at 07:08:35PM +0200, Laurent Dufour wrote: > In register_mem_sect_under_node() the system_state’s value is checked to > detect whether the operation the call is made during boot time or during an > hot-plug operation. Unfortunately, that check is wrong on some > architecture, and may lead to sections being registered under multiple > nodes if node's memory ranges are interleaved. > > This can be seen on PowerPC LPAR after multiple memory hot-plug and > hot-unplug operations are done. At the next reboot the node's memory ranges > can be interleaved and since the call to link_mem_sections() is made in > topology_init() while the system is in the SYSTEM_SCHEDULING state, the > node's id is not checked, and the sections registered multiple times. In > that case, the system is able to boot but later hot-plug operation may lead > to this panic because the node's links are correctly broken: > > ------------[ cut here ]------------ > kernel BUG at /Users/laurent/src/linux-ppc/mm/memory_hotplug.c:1084! > Oops: Exception in kernel mode, sig: 5 [#1] > LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries > Modules linked in: rpadlpar_io rpaphp pseries_rng rng_core vmx_crypto gf128mul binfmt_misc ip_tables x_tables xfs libcrc32c crc32c_vpmsum autofs4 > CPU: 8 PID: 10256 Comm: drmgr Not tainted 5.9.0-rc1+ #25 > NIP: c000000000403f34 LR: c000000000403f2c CTR: 0000000000000000 > REGS: c0000004876e3660 TRAP: 0700 Not tainted (5.9.0-rc1+) > MSR: 800000000282b033 CR: 24000448 XER: 20040000 > CFAR: c000000000846d20 IRQMASK: 0 > GPR00: c000000000403f2c c0000004876e38f0 c0000000012f6f00 ffffffffffffffef > GPR04: 0000000000000227 c0000004805ae680 0000000000000000 00000004886f0000 > GPR08: 0000000000000226 0000000000000003 0000000000000002 fffffffffffffffd > GPR12: 0000000088000484 c00000001ec96280 0000000000000000 0000000000000000 > GPR16: 0000000000000000 0000000000000000 0000000000000004 0000000000000003 > GPR20: c00000047814ffe0 c0000007ffff7c08 0000000000000010 c0000000013332c8 > GPR24: 0000000000000000 c0000000011f6cc0 0000000000000000 0000000000000000 > GPR28: ffffffffffffffef 0000000000000001 0000000150000000 0000000010000000 > NIP [c000000000403f34] add_memory_resource+0x244/0x340 > LR [c000000000403f2c] add_memory_resource+0x23c/0x340 > Call Trace: > [c0000004876e38f0] [c000000000403f2c] add_memory_resource+0x23c/0x340 (unreliable) > [c0000004876e39c0] [c00000000040408c] __add_memory+0x5c/0xf0 > [c0000004876e39f0] [c0000000000e2b94] dlpar_add_lmb+0x1b4/0x500 > [c0000004876e3ad0] [c0000000000e3888] dlpar_memory+0x1f8/0xb80 > [c0000004876e3b60] [c0000000000dc0d0] handle_dlpar_errorlog+0xc0/0x190 > [c0000004876e3bd0] [c0000000000dc398] dlpar_store+0x198/0x4a0 > [c0000004876e3c90] [c00000000072e630] kobj_attr_store+0x30/0x50 > [c0000004876e3cb0] [c00000000051f954] sysfs_kf_write+0x64/0x90 > [c0000004876e3cd0] [c00000000051ee40] kernfs_fop_write+0x1b0/0x290 > [c0000004876e3d20] [c000000000438dd8] vfs_write+0xe8/0x290 > [c0000004876e3d70] [c0000000004391ac] ksys_write+0xdc/0x130 > [c0000004876e3dc0] [c000000000034e40] system_call_exception+0x160/0x270 > [c0000004876e3e20] [c00000000000d740] system_call_common+0xf0/0x27c > Instruction dump: > 48442e35 60000000 0b030000 3cbe0001 7fa3eb78 7bc48402 38a5fffe 7ca5fa14 > 78a58402 48442db1 60000000 7c7c1b78 <0b030000> 7f23cb78 4bda371d 60000000 > ---[ end trace 562fd6c109cd0fb2 ]--- > > This patch addresses the root cause by not relying on the system_state > value to detect whether the call is due to a hot-plug operation or not. An > additional parameter is added to link_mem_sections() to tell the context of > the call and this parameter is propagated to register_mem_sect_under_node() > throuugh the walk_memory_blocks()'s call. > > Fixes: 4fbce633910e ("mm/memory_hotplug.c: make register_mem_sect_under_node() a callback of walk_memory_range()") > Signed-off-by: Laurent Dufour > Cc: stable@vger.kernel.org > Cc: Greg Kroah-Hartman > Cc: "Rafael J. Wysocki" > Cc: Andrew Morton > --- > drivers/base/node.c | 20 +++++++++++++++----- > include/linux/node.h | 6 +++--- > mm/memory_hotplug.c | 3 ++- > 3 files changed, 20 insertions(+), 9 deletions(-) > > diff --git a/drivers/base/node.c b/drivers/base/node.c > index 508b80f6329b..27f828eeb531 100644 > --- a/drivers/base/node.c > +++ b/drivers/base/node.c > @@ -762,14 +762,19 @@ static int __ref get_nid_for_pfn(unsigned long pfn) > } > > /* register memory section under specified node if it spans that node */ > +struct rmsun_args { > + int nid; > + bool hotadd; > +}; > static int register_mem_sect_under_node(struct memory_block *mem_blk, > - void *arg) > + void *args) > { > unsigned long memory_block_pfns = memory_block_size_bytes() / PAGE_SIZE; > unsigned long start_pfn = section_nr_to_pfn(mem_blk->start_section_nr); > unsigned long end_pfn = start_pfn + memory_block_pfns - 1; > - int ret, nid = *(int *)arg; > + int ret, nid = ((struct rmsun_args *)args)->nid; > unsigned long pfn; > + bool hotadd = ((struct rmsun_args *)args)->hotadd; > > for (pfn = start_pfn; pfn <= end_pfn; pfn++) { > int page_nid; > @@ -789,7 +794,7 @@ static int register_mem_sect_under_node(struct memory_block *mem_blk, > * case, during hotplug we know that all pages in the memory > * block belong to the same node. > */ > - if (system_state == SYSTEM_BOOTING) { > + if (!hotadd) { > page_nid = get_nid_for_pfn(pfn); > if (page_nid < 0) > continue; > @@ -832,10 +837,15 @@ void unregister_memory_block_under_nodes(struct memory_block *mem_blk) > kobject_name(&node_devices[mem_blk->nid]->dev.kobj)); > } > > -int link_mem_sections(int nid, unsigned long start_pfn, unsigned long end_pfn) > +int link_mem_sections(int nid, unsigned long start_pfn, unsigned long end_pfn, > + bool hotadd) > { > + struct rmsun_args args; > + > + args.nid = nid; > + args.hotadd = hotadd; > return walk_memory_blocks(PFN_PHYS(start_pfn), > - PFN_PHYS(end_pfn - start_pfn), (void *)&nid, > + PFN_PHYS(end_pfn - start_pfn), (void *)&args, > register_mem_sect_under_node); > } > > diff --git a/include/linux/node.h b/include/linux/node.h > index 4866f32a02d8..6df9a4548650 100644 > --- a/include/linux/node.h > +++ b/include/linux/node.h > @@ -100,10 +100,10 @@ typedef void (*node_registration_func_t)(struct node *); > > #if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_NUMA) > extern int link_mem_sections(int nid, unsigned long start_pfn, > - unsigned long end_pfn); > + unsigned long end_pfn, bool hotadd); > #else > static inline int link_mem_sections(int nid, unsigned long start_pfn, > - unsigned long end_pfn) > + unsigned long end_pfn, bool hotadd) Adding a random boolean flag to a function is a horrible way to do anything. Now you need to look up what that flag means every time you run across a caller, breaking your reading of what is happening. Make this two different functions please, that describe what they do, and have them call a common "helper function" that does the work with the flag if you really want to do this type of thing. link_mem_sections() and link_mem_sections_hotadd()? But not this way, please no. thanks, greg k-h