I have recently built linux kernel ver. 4.13.9, with config options
CONFIG_DEVMEM. I need access to kernel memory because of the homework, I need to look at the File Descriptor Table of some process in memory (yes, I know about
/proc filesystem, but I want to look at the exact structure in the kernel memory).
So, I built kernel with those options.
/dev/mem is working fine, but when I try to read something from
/dev/kmem, I'm getting following error:
user@debian-macbook:~$ sudo dd if=/dev/kmem bs=1k count=1 of=~/kmem dd: error reading '/dev/kmem': No such device or address 0+0 records in 0+0 records out 0 bytes copied, 6.9563e-05 s, 0.0 kB/s
/dev/kmem is exist:
user@debian-macbook:~$ file /dev/kmem /dev/kmem: character special (1/2)
I'm running Debian 9:
user@debian-macbook:~$ uname -a Linux debian-macbook 4.13.9 #1 SMP Mon Oct 23 01:17:31 MSK 2017 x86_64 GNU/Linux user@debian-macbook:~$ lsb_release -a No LSB modules are available. Distributor ID: Debian Description: Debian GNU/Linux 9.2 (stretch) Release: 9.2 Codename: stretch
Please, tell me what is wrong with /dev/kmem, or maybe suggest a different approach?
PS. Those options are enabled for sure:
user@debian-macbook:~$ cat /boot/config-4.13.9 | grep -Ee 'DEV(|K)MEM' CONFIG_DEVMEM=y CONFIG_DEVKMEM=y CONFIG_ARCH_HAS_DEVMEM_IS_ALLOWED=y # CONFIG_STRICT_DEVMEM is not set