[Crash-utility] [Question] page excluded: kernel virtual address

Sunday, 28 May 2023

Dear Mantainers,

I find there is an inevitable problem for linux-5.x ARM64 kdump that&nbsp;the error
"page excluded: kernel virtual address: xxx" will be occured when read the
address of ext4_super_block for&nbsp;ext4 filesystem in latest crash utility debugging
enviroment.

1)&nbsp;Here's my reproduce steps:

crash64&gt; mount
&nbsp; &nbsp; &nbsp;MOUNT &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; SUPERBLK &nbsp; &nbsp; TYPE &nbsp; DEVNAME &nbsp; DIRNAME
ffff000001e65180 ffff000001c1c000 rootfs none &nbsp; &nbsp; &nbsp;/
ffff00002ea66000 ffff00000288e000 ext4 &nbsp; /dev/root /
crash64&gt; struct super_block.s_fs_info -x ffff00000288e000&nbsp; s_fs_info =
0xffff000002885000,
crash64&gt; struct ext4_sb_info.s_es -x 0xffff000002885000
&nbsp; s_es = 0xffff0000043c2400,
crash64&gt; struct ext4_sb_info.s_es -x 0xffff0000043c2400
struct: page excluded: kernel virtual address: ffff0000043c2400 &nbsp;type:
"gdb_readmem_callback"
crash64&gt; rd 0xffff0000043c2400rd: page excluded: kernel virtual address:
ffff0000043c2400 &nbsp;type: "64-bit KVADDR"

crash64&gt; kmem -p 0xffff0000043c2400&nbsp; &nbsp; &nbsp; PAGE &nbsp;
&nbsp; &nbsp; PHYSICAL &nbsp; &nbsp; &nbsp;MAPPING &nbsp;
&nbsp; &nbsp; INDEX CNT FLAGS
fffffc000010f080 443c2000 ffff000002f93af0 &nbsp; &nbsp; &nbsp; &nbsp;0
&nbsp;2 ffff00000022036 referenced,uptodate,lru,active,private,mappedtodisk
crash64&gt; vtop 0xffff0000043c2400
VIRTUAL &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; PHYSICAL
ffff0000043c2400 &nbsp;443c2400

PAGE DIRECTORY: ffff80001163b000
&nbsp; &nbsp;PGD: ffff80001163b000 =&gt; 180000007fff9803
&nbsp; &nbsp;PUD: ffff00003fff9000 =&gt; 180000007fff8803
&nbsp; &nbsp;PMD: ffff00003fff8108 =&gt; 180000007ffe0803
&nbsp; &nbsp;PTE: ffff00003ffe0e10 =&gt; 680000443c2f07
&nbsp; PAGE: 443c2000

&nbsp; &nbsp; &nbsp;PTE &nbsp; &nbsp; &nbsp; &nbsp;PHYSICAL
&nbsp;FLAGS
680000443c2f07 &nbsp;443c2000 &nbsp;(VALID|SHARED|AF|NG|PXN|UXN)

&nbsp; &nbsp; &nbsp; PAGE &nbsp; &nbsp; &nbsp; PHYSICAL &nbsp;
&nbsp; &nbsp;MAPPING &nbsp; &nbsp; &nbsp; INDEX CNT FLAGS
fffffc000010f080 443c2000 ffff000002f93af0 &nbsp; &nbsp; &nbsp; &nbsp;0
&nbsp;2 ffff00000022036 referenced,uptodate,lru,active,private,mappedtodisk

2)&nbsp;Here's the kernel virtual kernel memory layout for my tested arm64 kernel
version 5.15, we can see&nbsp;0xffff0000043c2400 is in the kernel&nbsp;linear
memory region&nbsp;:
[ &nbsp; &nbsp;0.000000] Virtual kernel memory layout:[ &nbsp;
&nbsp;0.000000] &nbsp; &nbsp; modules : 0xffff800008000000 -
0xffff800010000000 &nbsp; ( &nbsp; 128 MB)
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; vmalloc : 0xffff800010000000 -
0xfffffbfff0000000 &nbsp; (126975 GB)
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; &nbsp; .text :
0xffff800010000000 - 0xffff8000111a0000 &nbsp; ( 18048 KB)
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; &nbsp; .init :
0xffff800011640000 - 0xffff800011760000 &nbsp; ( &nbsp;1152 KB)
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; .rodata : 0xffff8000111a0000 -
0xffff800011636000 &nbsp; ( &nbsp;4696 KB)
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; &nbsp; .data :
0xffff800011760000 - 0xffff800011902200 &nbsp; ( &nbsp;1673 KB)
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; &nbsp; &nbsp;.bss :
0xffff800011902200 - 0xffff8000119c6fb0 &nbsp; ( &nbsp; 788 KB)
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; fixed &nbsp; :
0xfffffbfffdbf9000 - 0xfffffbfffe000000 &nbsp; ( &nbsp;4124 KB)
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; PCI I/O : 0xfffffbfffe800000 -
0xfffffbffff800000 &nbsp; ( &nbsp; &nbsp;16 MB)
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; vmemmap : 0xfffffc0000000000 -
0xfffffe0000000000 &nbsp; ( &nbsp;2048 GB maximum)
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; 0xfffffc0000000000 - 0xfffffc0001000000 &nbsp; ( &nbsp;
&nbsp;16 MB actual)
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; memory &nbsp;:
0xffff000000000000 - 0xffff000040000000 &nbsp; ( &nbsp;1024 MB)
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; PAGE_OFFSET &nbsp;:
0xffff000000000000
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; KIMAGE_VADDR &nbsp;:
0xffff800010000000
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; kimage_voffset :
0xffff7fffcfe00000
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; PHYS_OFFSET &nbsp;:
0x40000000
[ &nbsp; &nbsp;0.000000] &nbsp; &nbsp; start memory &nbsp;:
0x40000000

I have no idea whether this problem is something wrong with crash utility. Could anybody
please help this?

Thanks

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

[Crash-utility] [Question] page excluded: kernel virtual address