Hi, Qianli
On Tue, Jun 28, 2022 at 9:55 AM lijiang <lijiang@xxxxxxxxxx> wrote:
Hi, Kazu and QianliOn Tue, Jun 28, 2022 at 9:17 AM HAGIO KAZUHITO(萩尾 一仁) <k-hagio-ab@xxxxxxx> 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
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)
[ 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@xxxxxxxxx> 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@xxxxxxxxx> 于2022年6月24日周五 00:14写道：
>>>
>>> From: Qianli Zhao <qianli.zhao@xxxxxxxxxx>
>>>
>>> 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@xxxxxxxxxx>
>>> ---
>>> 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
>>>
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