I recently had to kernel debug my kext again. It used to have all symbols available while kernel debugging an earlier 10.11 a while ago.
I build my kext with dwarf-with-dsym against an 10.9 SDK and I am assuming my build settings are OK, since it used to work.
When connecting to the panic'd system, I do (or - more precicly my script does):
(lldb) target create "/Library/Developer/KDKs/KDK_10.11.3_15D13b.kdk/System/Library/Kernels/kernel"
warning: 'kernel' contains a debug script. To run this script in this debug session:
command script import "/Library/Developer/KDKs/KDK_10.11.3_15D13b.kdk/System/Library/Kernels/kernel.dSYM/Contents/Resources/DWARF/../Python/kernel.py"
To run all discovered debug scripts in this session:
settings set target.load-script-from-symbol-file true
Current executable set to '/Library/Developer/KDKs/KDK_10.11.3_15D13b.kdk/System/Library/Kernels/kernel' (x86_64).
(lldb) settings set target.load-script-from-symbol-file true
Loading kernel debugging from /Library/Developer/KDKs/KDK_10.11.3_15D13b.kdk/System/Library/Kernels/kernel.dSYM/Contents/Resources/DWARF/../Python/kernel.py
LLDB version lldb-340.4.119
settings set target.process.python-os-plugin-path "/Library/Developer/KDKs/KDK_10.11.3_15D13b.kdk/System/Library/Kernels/kernel.dSYM/Contents/Resources/DWARF/../Python/lldbmacros/core/operating_system.py"
settings set target.trap-handler-names hndl_allintrs hndl_alltraps trap_from_kernel hndl_double_fault hndl_machine_check _fleh_prefabt _ExceptionVectorsBase _ExceptionVectorsTable _fleh_undef _fleh_dataabt _fleh_irq _fleh_decirq _fleh_fiq_generic _fleh_dec
command script import "/Library/Developer/KDKs/KDK_10.11.3_15D13b.kdk/System/Library/Kernels/kernel.dSYM/Contents/Resources/DWARF/../Python/lldbmacros/xnu.py"
xnu debug macros loaded successfully. Run showlldbtypesummaries to enable type summaries.
(lldb) showlldbtypesummaries
Successfully enabled the kernel type summaries. Please run 'showlldbtypesummaries disable' to disable the summary feature.
(lldb) settings set platform.plugin.darwin-kernel.kext-directories my-verified-path-to-kext-and-dsym
(lldb) kdp-remote 192.168.0.42
Version: Darwin Kernel Version 15.3.0: Thu Dec 10 18:40:58 PST 2015; root:xnu-3248.30.4~1/RELEASE_X86_64; UUID=DECC9F02-27D7-31F0-9599-A9EF2873902C; stext=0xffffff800e800000
Kernel UUID: DECC9F02-27D7-31F0-9599-A9EF2873902C
Load Address: 0xffffff800e800000
WARNING: Unable to locate kernel binary on the debugger system.
Target arch: x86_64
Instantiating threads completely from saved state in memory.
FATAL FAILURE: Unable to find kdp_thread state for this connection.
(lldb) bt
Process 1 stopped
* thread #1: tid = 0x0001, 0xffffff7f91071475, stop reason = signal SIGSTOP
frame #0: 0xffffff7f91071475
-> 0xffffff7f91071475: movq (%rcx), %rdx
0xffffff7f91071478: movq %rcx, %rdi
0xffffff7f9107147b: callq *0x998(%rdx)
0xffffff7f91071481: movq %rax, -0x8(%rbp)
* thread #1: tid = 0x0001, 0xffffff7f91071475, stop reason = signal SIGSTOP
* frame #0: 0xffffff7f91071475
frame #1: 0xffffff7f9107106a
frame #2: 0xffffff7f91073bf9
frame #3: 0xffffff7f9106f47c
frame #4: 0xffffff7f9106cf54
frame #5: 0xffffff800eee1777
frame #6: 0xffffff800e99be20
frame #7: 0xffffff800e8e3ef3
frame #8: 0xffffff800e8c78a8
frame #9: 0xffffff800e8d72e5
frame #10: 0xffffff800e9bcd2a
... and then I am clueless what went wrong.
Thanks for any hints what to else to check...
Hagen.