[Crash-utility] Re: seek error when loading /proc/kcore with type: "page_offset_base"

On 24/08/05 02:30PM, Tao Liu wrote: > For live debug, I noticed for cachyos, kallsyms will output 0 address > for kernel symbols even as root: > > [root@cachyos-x8664 ~]# cat /proc/kallsyms |less > 0000000000000000 A fixed_percpu_data > 0000000000000000 A __per_cpu_start > 0000000000000000 A cpu_debug_store > 0000000000000000 A irq_stack_backing_store > ... > [root@cachyos-x8664 ~]# cat /proc/sys/kernel/kptr_restrict > 2 > > This would prevent crash to detect the kaslr info. To avoid this, > please enable the address presenting by: > > [root@cachyos-x8664 ~]# echo 0 > /proc/sys/kernel/kptr_restrict > [root@cachyos-x8664 ~]# cat /proc/kallsyms |less > 0000000000000000 A fixed_percpu_data > 0000000000000000 A __per_cpu_start > 0000000000001000 A cpu_debug_store > 0000000000002000 A irq_stack_backing_store > ... > > then invoke the crash for live debug will have no problem. Tao, thanks for surfacing this. I'm curious why the commit that Kazu referenced also appears to solve the problem. I can get live debug to work when I compile crash from HEAD without enabling the addresses. Do you know why? https://github.com/crash-utility/crash/commit/6752571d8d782d07537a258a1ec...

> Also so if you are dealing with the newest kernel, both makedumpfile and > crash will need to be newest, otherwise some bugs you may encounter. Will do! > Thanks, > Tao Liu