Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933723AbeAIHYy (ORCPT + 1 other); Tue, 9 Jan 2018 02:24:54 -0500 Received: from mx1.redhat.com ([209.132.183.28]:40456 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933387AbeAIHYw (ORCPT ); Tue, 9 Jan 2018 02:24:52 -0500 Date: Tue, 9 Jan 2018 15:24:40 +0800 From: Dave Young To: Baoquan He Cc: "Kirill A. Shutemov" , Ingo Molnar , Mike Galbraith , Andrew Morton , "Kirill A. Shutemov" , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Andy Lutomirski , Borislav Petkov , Cyrill Gorcunov , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , linux-mm@kvack.org, Vivek Goyal , kexec@lists.infradead.org Subject: Re: [PATCH 4.14 023/159] mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y Message-ID: <20180109072440.GA6521@dhcp-128-65.nay.redhat.com> References: <20171222084623.668990192@linuxfoundation.org> <20171222084625.007160464@linuxfoundation.org> <1515302062.6507.18.camel@gmx.de> <20180108160444.2ol4fvgqbxnjmlpg@gmail.com> <20180108174653.7muglyihpngxp5tl@black.fi.intel.com> <20180109001303.dy73bpixsaegn4ol@node.shutemov.name> <20180109010927.GA2082@dhcp-128-65.nay.redhat.com> <20180109054131.GB1935@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180109054131.GB1935@localhost.localdomain> User-Agent: Mutt/1.9.1 (2017-09-22) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Tue, 09 Jan 2018 07:24:52 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On 01/09/18 at 01:41pm, Baoquan He wrote: > On 01/09/18 at 09:09am, Dave Young wrote: > > On 01/09/18 at 03:13am, Kirill A. Shutemov wrote: > > > On Mon, Jan 08, 2018 at 08:46:53PM +0300, Kirill A. Shutemov wrote: > > > > On Mon, Jan 08, 2018 at 04:04:44PM +0000, Ingo Molnar wrote: > > > > > > > > > > hi Kirill, > > > > > > > > > > As Mike reported it below, your 5-level paging related upstream commit > > > > > 83e3c48729d9 and all its followup fixes: > > > > > > > > > > 83e3c48729d9: mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y > > > > > 629a359bdb0e: mm/sparsemem: Fix ARM64 boot crash when CONFIG_SPARSEMEM_EXTREME=y > > > > > d09cfbbfa0f7: mm/sparse.c: wrong allocation for mem_section > > > > > > > > > > ... still breaks kexec - and that now regresses -stable as well. > > > > > > > > > > Given that 5-level paging now syntactically depends on having this commit, if we > > > > > fully revert this then we'll have to disable 5-level paging as well. > > > > > > This *should* help. > > > > > > Mike, could you test this? (On top of the rest of the fixes.) > > > > > > Sorry for the mess. > > > > > > From 100fd567754f1457be94732046aefca204c842d2 Mon Sep 17 00:00:00 2001 > > > From: "Kirill A. Shutemov" > > > Date: Tue, 9 Jan 2018 02:55:47 +0300 > > > Subject: [PATCH] kdump: Write a correct address of mem_section into vmcoreinfo > > > > > > Depending on configuration mem_section can now be an array or a pointer > > > to an array allocated dynamically. In most cases, we can continue to refer > > > to it as 'mem_section' regardless of what it is. > > > > > > But there's one exception: '&mem_section' means "address of the array" if > > > mem_section is an array, but if mem_section is a pointer, it would mean > > > "address of the pointer". > > > > > > We've stepped onto this in kdump code. VMCOREINFO_SYMBOL(mem_section) > > > writes down address of pointer into vmcoreinfo, not array as we wanted. > > > > > > Let's introduce VMCOREINFO_ARRAY() that would handle the situation > > > correctly for both cases. > > > > > > Signed-off-by: Kirill A. Shutemov > > > Fixes: 83e3c48729d9 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y") > > > --- > > > include/linux/crash_core.h | 2 ++ > > > kernel/crash_core.c | 2 +- > > > 2 files changed, 3 insertions(+), 1 deletion(-) > > > > > > diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h > > > index 06097ef30449..83ae04950269 100644 > > > --- a/include/linux/crash_core.h > > > +++ b/include/linux/crash_core.h > > > @@ -42,6 +42,8 @@ phys_addr_t paddr_vmcoreinfo_note(void); > > > vmcoreinfo_append_str("PAGESIZE=%ld\n", value) > > > #define VMCOREINFO_SYMBOL(name) \ > > > vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)&name) > > > +#define VMCOREINFO_ARRAY(name) \ > > > > Thanks for the patch, I have a similar patch but makedumpfile maintainer > > is looking at a userspace fix instead. > > Seems we should add lkml to CC next time so that people can watch it. Yes, agreed. > > > As for the macro name, VMCOREINFO_SYMBOL_ARRAY sounds better. > > I still think using vmcoreinfo_append_str is better. Unless we replace > all array variables with the newly added macro. > > vmcoreinfo_append_str("SYMBOL(mem_section)=%lx\n", > (unsigned long)mem_section); I have no strong opinion, either change all array uses or just introduce the macro and start to use it from now on if we have similar array symbols. > > > > > + vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)name) > > > #define VMCOREINFO_SIZE(name) \ > > > vmcoreinfo_append_str("SIZE(%s)=%lu\n", #name, \ > > > (unsigned long)sizeof(name)) > > > diff --git a/kernel/crash_core.c b/kernel/crash_core.c > > > index b3663896278e..d4122a837477 100644 > > > --- a/kernel/crash_core.c > > > +++ b/kernel/crash_core.c > > > @@ -410,7 +410,7 @@ static int __init crash_save_vmcoreinfo_init(void) > > > VMCOREINFO_SYMBOL(contig_page_data); > > > #endif > > > #ifdef CONFIG_SPARSEMEM > > > - VMCOREINFO_SYMBOL(mem_section); > > > + VMCOREINFO_ARRAY(mem_section); > > > VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS); > > > VMCOREINFO_STRUCT_SIZE(mem_section); > > > VMCOREINFO_OFFSET(mem_section, section_mem_map); > > > -- > > > Kirill A. Shutemov > > > > Thanks > > Dave Thanks Dave