Re: [Crash-utility] [PATCH] arm64: Fix for st->_stext_vmlinux not initialized when set VA_BITS_ACTUAL

Hi, Qianli On Tue, Jun 28, 2022 at 9:55 AM lijiang <lijiang(a)redhat.com&gt; wrote: > > Hi, Kazu and Qianli > > On Tue, Jun 28, 2022 at 9:17 AM HAGIO KAZUHITO(萩尾　一仁) <k-hagio-ab(a)nec.com&gt; wrote: >> >> Hi Qianli, >> >> thanks for the patch and explanation. I was off. >> >> On 2022/06/27 11:24, qianli zhao wrote: >> > Hi,Kazu >> > >> > Would you like to help review this patch? >> >> Sure, I think I can review it this week. >> >> Lianbo, can you possibly reproduce and test this? > > > OK, I will have a look and give feedback later. Could you please point out the kernel version? I tried it with the latest kernel and did not reproduce this issue when disabling the kaslr feature(# CONFIG_RANDOMIZE_BASE is not set or nokaslr) crash > help -m .. vmalloc_start_addr: ffff800008000000 vmalloc_end: fffffbffefffffff modules_vaddr: ffff800000000000 modules_end: ffff800007ffffff vmemmap_vaddr: fffffc0000000000 vmemmap_end: fffffdffffffffff ... And the following information is dumped from the kernel(commit: 941e3e791269) ... [ 0.000000] Virtual kernel memory layout: [ 0.000000] modules : 0xffff800000000000 - 0xffff800008000000 ( 128 MB) [ 0.000000] vmalloc : 0xffff800008000000 - 0xfffffbfff0000000 (126975 GB) ... [ 0.000000] vmemmap : 0xfffffc0000000000 - 0xfffffe0000000000 ( 2048 GB maximum) [ 0.000000] 0xfffffc000000bc00 - 0xfffffc023df40000 ( 9183 MB actual) I'm wondering if that can be only reproduced on the old kernel, right? Or did I miss anything else? Thanks. Lianbo > >> >> Kazu >> >> > >> > qianli zhao <zhaoqianligood(a)gmail.com&gt; 于2022年6月24日周五 10:56写道： >> > >> >> >> >> Hi,all >> >> >> >> Here's some explanation for this patch >> >> >> >> Without patch: >> >> Consider the following scenario >> >> ->arm64_init(PRE_GDB) >> >> case PRE_GDB: >> >> ... >> >> 292 } else if (ms->VA_BITS_ACTUAL) { >> >> 293 ms->modules_vaddr = >> >> (st->_stext_vmlinux & TEXT_OFFSET_MASK) - >> >> ARM64_MODULES_VSIZE;-->//ms->modules_vaddr=0xfffffffff8000000 >> >> 294 ms->modules_end = >> >> ms->modules_vaddr + ARM64_MODULES_VSIZE >> >> -1;--->//ms->modules_end=0xffffffffffffffff >> >> 295 ms->vmalloc_start_addr = >> >> ms->modules_end + 1;--->//ms->vmalloc_start_addr=0 >> >> 296 } else { >> >> .... >> >> } >> >> arm64_calc_kimage_voffset(); >> >> ..... >> >> >> >> Since arm64_calc_kimage_voffset() depends on vmalloc_start_addr, >> >> kimage_voffset cannot be calculated correctly. >> >> >> >> st->_stext_vmlinux can be initialized in numeric_forward(),just set >> >> st->_stext_vmlinux to UNINITIALIZED. >> >> >> >> ============ >> >> log as below: >> >> >> >> $ ~/crash/crash/crash vmlinux DDRCS0.bin@0x80000000 --machdep vabits_actual=48 >> >> >> >> crash 8.0.1++ >> >> Copyright (C) 2002-2022 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, 2020-2022 NEC Corporation >> >> Copyright (C) 1999, 2002, 2007 Silicon Graphics, Inc. >> >> Copyright (C) 1999, 2000, 2001, 2002 Mission Critical Linux, Inc. >> >> Copyright (C) 2015, 2021 VMware, 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. >> >> >> >> NOTE: setting vabits_actual to: 48 >> >> >> >> WARNING: kimage_voffset cannot be determined from the dumpfile. >> >> Try using the command line option: --machdep kimage_voffset=<addr> >> >> GNU gdb (GDB) 10.2 >> >> Copyright (C) 2021 Free Software Foundation, Inc. >> >> License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> >> >> 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 "--host=x86_64-pc-linux-gnu >> >> --target=aarch64-elf-linux". >> >> Type "show configuration" for configuration details. >> >> Find the GDB manual and other documentation resources online at: >> >> <http://www.gnu.org/software/gdb/documentation/>;. >> >> >> >> For help, type "help". >> >> Type "apropos word" to search for commands related to "word"... >> >> >> >> crash: read error: kernel virtual address: ffff80001083d4a0 type: >> >> "kernel_config_data" >> >> WARNING: cannot read kernel_config_data >> >> crash: read error: kernel virtual address: ffff80001170e798 type: "possible" >> >> WARNING: cannot read cpu_possible_map >> >> crash: read error: kernel virtual address: ffff80001170e7a8 type: "present" >> >> WARNING: cannot read cpu_present_map >> >> crash: read error: kernel virtual address: ffff80001170e788 type: "online" >> >> WARNING: cannot read cpu_online_map >> >> crash: read error: kernel virtual address: ffff80001170e7c0 type: "active" >> >> WARNING: cannot read cpu_active_map >> >> crash: read error: kernel virtual address: ffff8000122e00f0 type: >> >> "shadow_timekeeper xtime_sec" >> >> crash: read error: kernel virtual address: ffff80001171dc04 type: "init_uts_ns" >> >> crash: vmlinux and /var/tmp/ramdump_elf_m2ivkg do not match! >> >> >> >> Usage: >> >> >> >> crash [OPTION]... NAMELIST MEMORY-IMAGE[@ADDRESS] (dumpfile form) >> >> crash [OPTION]... [NAMELIST] (live system form) >> >> >> >> Enter "crash -h" for details. >> >> >> >> Qianli Zhao <zhaoqianligood(a)gmail.com&gt; 于2022年6月24日周五 00:14写道： >> >>> >> >>> From: Qianli Zhao <qianli.zhao(a)horizon.ai&gt; >> >>> >> >>> Setting st->_stext_vmlinux to UNINITIALIZED to search for "_stext" from the vmlinux >> >>> Without the patch, if we do not enable kaslr, will get the wrong >> >>> MODULES/VMALLOC ranges, cause parsing dump failure >> >>> >> >>> Signed-off-by: Qianli Zhao <qianli.zhao(a)horizon.ai&gt; >> >>> --- >> >>> arm64.c | 3 +++ >> >>> 1 file changed, 3 insertions(+) >> >>> >> >>> diff --git a/arm64.c b/arm64.c >> >>> index 0f615cf..4458a66 100644 >> >>> --- a/arm64.c >> >>> +++ b/arm64.c >> >>> @@ -149,6 +149,9 @@ arm64_init(int when) >> >>> >> >>> ms = machdep->machspec; >> >>> >> >>> + if (ms->VA_BITS_ACTUAL) >> >>> + st->_stext_vmlinux = UNINITIALIZED; >> >>> + >> >>> if (!ms->kimage_voffset && STREQ(pc->live_memsrc, "/dev/crash")) >> >>> ioctl(pc->mfd, DEV_CRASH_ARCH_DATA, &ms->kimage_voffset); >> >>> >> >>> -- >> >>> 2.17.1 >> >>>