lx-symbols: Python Exception <class 'gdb.MemoryError'> Cannot access memory at address 0xff

Question

I'm trying to load the lx-symbols from the kernel. but it keeps showing me the following error:

(gdb) lx-symbols
loading vmlinux
Python Exception <class 'gdb.MemoryError'> Cannot access memory at address 0xffffffff824fb470: 
Error occurred in Python command: Cannot access memory at address 0xffffffff824fb470

Now I was successfully able to load the lx-symbols before from the same build(not sure if this is the correct terminology) but don't know why I can load it anymore.

Now, When I first connect to the remote machine via gdb it used to shows the build trace like the following:

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Reading symbols from ./vmlinux...done.
(gdb) target remote: 1235
Remote debugging using : 1235
native_safe_halt ()
    at /build/linux-hwe-22QmxS/linux-hwe-5.3.0/arch/x86/include/asm/irqflags.h:61
61    /build/linux-hwe-22QmxS/linux-hwe-5.3.0/arch/x86/include/asm/irqflags.h: No such file or directory.

Now when I connect to the remote kernel, it is showing me just this :

(gdb) target remote :1235
Remote debugging using :1235
0xffffffff81a98522 in __irqentry_text_end ()

I notice that the build trace /build/linux-hwe-22QmxS/linux-hwe-5.3.0/arch/x86/include/asm/irqflags.h:61 61 disappear (I did not make any changes to the configuration or setting).

This is the second time I'm facing the same problem. At the first time, I thought maybe i accidentally make some changes but as the problem occurs again, this time I'm quite sure I did not make any changes.

I have my .gdbinit file with the correct path.

add-auto-load-safe-path /../../ubuntu-bionic/debian/build/build-generic/vmlinux-gdb.py

I checked if the source is loading correctly by using the this:

(gdb) source /home/../../ubuntu-bionic/debian/build/build-generic/vmlinux-gdb.py

It didn't throw me any error. So, I guess the source is loading correctly. I just don't know what else to do. Please help.

Answer 1

Try to add to the kernel boot parameters "nokaslr" and/or build with CONFIG_RANDOMIZE_BASE=n