From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]) by bombadil.infradead.org with esmtps (Exim 4.89 #1 (Red Hat Linux)) id 1eXIYH-0003Wj-9x for kexec@lists.infradead.org; Fri, 05 Jan 2018 03:20:17 +0000 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6B0073DFCD for ; Fri, 5 Jan 2018 03:20:02 +0000 (UTC) Date: Fri, 5 Jan 2018 11:19:55 +0800 From: Dave Young Subject: Re: makedumpfile saving vmcore fails with dynamically allocated mem_section (was: Re: [PATCH] handle renamed init_level4_pgt -> init_top_pgt) Message-ID: <20180105031955.GA28305@dhcp-128-65.nay.redhat.com> References: <727199273.2520585.1515010910495.JavaMail.zimbra@redhat.com> <20180105023828.GA11054@dhcp-128-65.nay.redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20180105023828.GA11054@dhcp-128-65.nay.redhat.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Dave Anderson Cc: kexec@lists.infradead.org On 01/05/18 at 10:38am, Dave Young wrote: > On 01/03/18 at 03:21pm, Dave Anderson wrote: > > > > > > ----- Original Message ----- > > > > > On 01/02/18 at 05:08pm, Baoquan He wrote: > > > > On 01/02/18 at 04:57pm, Dave Young wrote: > > > > > The root cause is this commit makes mem_section as a pointer instead of > > > > > the static array. > > > > > > > > > > VMCOREINFO_SYMBOL() expand it as &mem_section, this is not correct in > > > > > the test case any more. > > > > > > > > > > This hack code works for me: > > > > > > > > > > diff --git a/kernel/crash_core.c b/kernel/crash_core.c > > > > > index b3663896278e..f5fe6068ae39 100644 > > > > > --- a/kernel/crash_core.c > > > > > +++ b/kernel/crash_core.c > > > > > @@ -376,6 +376,8 @@ phys_addr_t __weak paddr_vmcoreinfo_note(void) > > > > > { > > > > > return __pa(vmcoreinfo_note); > > > > > } > > > > > +#define VMCOREINFO_SYMBOL_HACK(name) \ > > > > > + vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)name) > > > > > > > > Oh, you made a new one. We may use vmcoreinfo_append_str directly since > > > > there's an existing one in crash_save_vmcoreinfo(): > > > > > > Yes, it should be something like this instead, this should ensure > > > makedumpfile maybe crash tool works without any modifications, > > > waiting for feedback from Atsushi, also ccing Dave for crash utility > > > potential issue. > > > > Yeah, I ran into that issue when testing 4.15, and fixed it upstream: > > > > https://github.com/crash-utility/crash/commit/264f22dafe9f37780c4113fd08e8d5b2138edbce > > > > commit 264f22dafe9f37780c4113fd08e8d5b2138edbce > > Author: Dave Anderson > > Date: Wed Nov 29 15:28:41 2017 -0500 > > > > Fix for Linux 4.15 and later kernels that are configured with > > CONFIG_SPARSEMEM_EXTREME, and that contain kernel commit > > 83e3c48729d9ebb7af5a31a504f3fd6aff0348c4, titled "mm/sparsemem: > > Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y". > > Without the patch, kernels configured with SPARSEMEM_EXTREME > > have changed the data type of "mem_section" from an array to > > a pointer, leading to errors in commands such as "kmem -p", > > "kmem -n", "kmem -s", and any other command that translates a > > physical address to its page struct address. > > (anderson@redhat.com) > > > > Hi Dave, > > I tried latest crash tool, but segment fault happened, I put the > vmlinux/vmcore in below url, could you have a look?: > http://people.redhat.com/ruyang/rhbz1528542/127.0.0.1-2018-01-05-10:29:23/ > > --- > crash 7.2.0++ > Copyright (C) 2002-2017 Red Hat, Inc. > Copyright (C) 2004, 2005, 2006, 2010 IBM Corporation > Copyright (C) 1999-2006 Hewlett-Packard Co > Copyright (C) 2005, 2006, 2011, 2012 Fujitsu Limited > Copyright (C) 2006, 2007 VA Linux Systems Japan K.K. > Copyright (C) 2005, 2011 NEC Corporation > Copyright (C) 1999, 2002, 2007 Silicon Graphics, Inc. > Copyright (C) 1999, 2000, 2001, 2002 Mission Critical Linux, Inc. > This program is free software, covered by the GNU General Public License, > and you are welcome to change it and/or distribute copies of it under > certain conditions. Enter "help copying" to see the conditions. > This program has absolutely no warranty. Enter "help warranty" for details. > > GNU gdb (GDB) 7.6 > Copyright (C) 2013 Free Software Foundation, Inc. > License GPLv3+: GNU GPL version 3 or later > This is free software: you are free to change and redistribute it. > There is NO WARRANTY, to the extent permitted by law. Type "show copying" > and "show warranty" for details. > This GDB was configured as "x86_64-unknown-linux-gnu"... > > WARNING: could not find MAGIC_START! > WARNING: kernel version inconsistency between vmlinux and dumpfile > > please wait... (gathering task table data) > WARNING: duplicate idle tasks? > > WARNING: duplicate idle tasks? > please wait... (determining panic task) > WARNING: active task ffffffff81e90536 on cpu 0 not found in PID hash > > [ 1156.567444] crash[2964]: segfault at 7175228 ip 00000000004bf39e sp 00007ffd5dce3f30 error 6 in crash[400000+6da000] > Segmentation fault (core dumped) > > The tested kernel applied below patch (a tuned patch according to bhe's > suggestion): > > --- > kernel/crash_core.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > --- linux.orig/kernel/crash_core.c > +++ linux/kernel/crash_core.c > @@ -410,7 +410,8 @@ static int __init crash_save_vmcoreinfo_ > VMCOREINFO_SYMBOL(contig_page_data); > #endif > #ifdef CONFIG_SPARSEMEM > - VMCOREINFO_SYMBOL(mem_section); > + vmcoreinfo_append_str("SYMBOL(mem_section)=%lx\n", > + (unsigned long)mem_section); > VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS); > VMCOREINFO_STRUCT_SIZE(mem_section); > VMCOREINFO_OFFSET(mem_section, section_mem_map); > > BTW, crash works fine with CONFIG_SPARSEMEM_EXTREME being disabled. _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec