Hi Jose, On Tue, Aug 6, 2024 at 2:46 PM Jose Fernandez <jose.fernandez@xxxxxxxxx> wrote: > > 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/6752571d8d782d07537a258a1ec8919ebd1308ad > Not sure... If your crash didn't have the above patch integrated, then it definitely will fail. I compiled the upstream crash on the cachyos, which already have the patch, but failed due to the 0 address in kallsyms for live debug, after setting kptr_restrict then it worked. I guess your env is not the same as mine... Thanks, Tao Liu > > 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 > -- Crash-utility mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxxxxxx https://${domain_name}/admin/lists/devel.lists.crash-utility.osci.io/ Contribution Guidelines: https://github.com/crash-utility/crash/wiki
