[lldb-dev] show backtrace for macOS remote threads.

[Zohar Cabeli via lldb-dev]

Hello All,

I'm currently debugging my xnu based kernel module and I'm using the
API of kernel.py
from the KDK.

I need some advice about how to print the backtraces of all kernel space
threads or all kernel space threads per task.

Here's what I've done so far :

1. getting kernel_task id

(lldb) showalltasks

task                 vm_map               ipc_space            #acts flags
  pid       process             io_policy  wq_state  command

0xffffff800d828550   0xffffff800a1038d8   0xffffff800d5d17c0     140
    0   0xffffff8007abb460                -1 -1 -1    kernel_task

2. dump all threads which belongs to kernel_task

(lldb) showtaskthreads 0xffffff800d828550

task                 vm_map               ipc_space            #acts flags
  pid       process             io_policy  wq_state  command

0xffffff800d828550   0xffffff800a1038d8   0xffffff800d5d17c0     140
    0   0xffffff8007abb460                -1 -1 -1    kernel_task

thread                   thread_id  processor            base   pri
sched_mode      io_policy       state    ast          waitq
            wait_event           wmesg                thread_name

0xffffff8007acf098       0x65       0xffffff8007a8a7b8   92     92
fixed bound                     WU       L            0xffffff804119e550
            0xffffff8007a87a30 <vm_page_free_wanted>


0xffffff800d83f4c0       0x66       0xffffff8007a8a7b8   0      0
fixed bound                     RI       L


0xffffff800d83f958       0x67       0xffffff8041ad6000   95     95
fixed                           WU       L            0xffffff804119c240
            0xffffff8007303840 <sched_timeshare_maintenance_continue>
                sched_maintenance_thread

0xffffff800d83fdf0       0x68       0xffffff8041ad6000   80     80
fixed                           WU       L            0xffffff804119e850
            0xffffff8007acf9f0

0xffffff800d83f028       0x69       0xffffff8007a8a7b8   93     93
fixed                           WU                    0xffffff804119e5e0
            0xffffff8007acfa08

0xffffff800d83eb90       0x6a       0xffffff8041ad6000   80     80
fixed                           WU                    0xffffff80411a07a0
            0xffffff8007acf9c8


Now I've got record for each thread in the kernel_task along with info such
as thread id, but not the backtrace ...
is there any command in the KDK which can retrieve the backtrace for all
the threads per task or any single thread ?

Thanks ,
Zohar
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