Debugging the Linux Kernel with GDB
Kieran Bingham
Debugging the Linux Kernel with GDB
● Many of us need to debug the Linux kernel
● Proprietary tools like Trace32 and DS-5 are $$$
● Open source debuggers like GDB lack ‘kernel awareness’ features
found in proprietary tools
● What exists today
● How you can use it to get data
● How can we make it better
{They, we} wouldn’t … would {they, we} ?
Linus (~2000)
I don't like debuggers. Never
have, probably never will. I use
gdb all the time, but I tend to
use it not as a debugger, but as You can use a kernel debugger if you
a disassembler on steroids that want to, and I won't give you the cold
you can program. shoulder because you have "sullied"
yourself. But I'm not going to help you
use one, and I would frankly prefer
people not to use kernel debuggers that
much.
http://lwn.net/2000/0914/a/lt-debugger.php3
Why?
There is always code
to debug.
We don’t always write
it ourselves.
But we do have to fix it
How can we improve free tools
● Both LLDB and GDB have extension capabilities
● Jan Kizka has led the way, adding Kernel support for GDB
● OpenOCD provides free JTAG connectivity
● Automated testing needed
Coming Up
● Target options
○ KGDB
○ QEmu/KVM/UML
○ JTAG
○ Core Dumps
● Linux Awareness
○ Thread Awareness
○ Module Support
○ Data retrieval
○ Extending with Python
● Q+A
Targets for debugging Linux with GDB
● GDB client using the gdbremote protocol
a. Connection to a KGDB stub in a running kernel
b. Connect to a QEmu stub running a virtual kernel environment
c. To a gdbremote compliant JTAG probe, such as OpenOCD
● GDB session on host
a. Core Dump file
b. UML Kernel
Core Dumps
KGDB JTAG
Good Better
Qemu
Targets: KGDB with GDB
● Debug stub in the kernel compliant with gdbremote protocol
○ Enable with CONFIG_KGDB
+ Already supported on many platforms
+ All kernel threads enumerated in GDB (via gdbremote)
- Requires cooperation between debugger and kernel stub
- Less suitable for serious crashes
- Isn’t enabled on production systems
- Requires enough support for serial or ethernet
Host Gdbremote Target
serial/ethernet Linux
GDB KGDB
Targets: QEmu
+ Qemu is open source and has gdbremote stub
+ No ‘real’ hardware required
+ Good for testing generic kernel code on many architectures
+ Good environment for developing Kernel Awareness extensions
- Unlikely to be useful for SoC or board related issues
Development Host
Qemu
GDB Client GDB Stub Server
Linux Kernel
Targets : Qemu (Example)
qemu-system-arm -kernel ./zImage -dtb ./vexpress-v2p-ca15-tc1.dtb -M vexpress-a15 -smp 2 -m 1024 -append 'root=/dev/nfs nfsroot=10.0.2.2:/opt/root/armv7/,tcp,v3 rw
ip=dhcp mem=1024M raid=noautodetect rootwait console=ttyAMA0,38400n8 devtmpfs.mount=0' -nographic -gdb tcp::32770
[ 0.000000] Booting Linux on physical CPU 0x0
[ 0.000000] Linux version 4.6.0-rc1 (kbingham@CookieMonster) (gcc version 5.2.1 20151010 (Ubuntu 5.2.1-22ubuntu1) ) #13 SMP Thu Mar 31 10:33:19 BST 2016
[ 0.000000] CPU: ARMv7 Processor [412fc0f1] revision 1 (ARMv7), cr=10c5387d
[ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache
[ 0.000000] Machine model: V2P-CA15
[ ….. ]
[ 3.989042] IP-Config: Got DHCP answer from 10.0.2.2, my address is 10.0.2.15
[ 3.991451] IP-Config: Complete:
[ 3.991672] device=eth0, hwaddr=52:54:00:12:34:56, ipaddr=10.0.2.15, mask=255.255.255.0, gw=10.0.2.2
[ 3.991900] host=10.0.2.15, domain=, nis-domain=(none)
[ 3.992039] bootserver=10.0.2.2, rootserver=10.0.2.2, rootpath= nameserver0=10.0.2.3
arm-linux-gdb ./linux/vmlinux -iex 'add-auto-load-safe-path ./linux' -ex 'target remote localhost:32770'
Remote debugging using localhost:32770
cpu_v7_do_idle () at /home/lkd/sources/linux/arch/arm/mm/proc-v7.S:74
74 ret lr
(gdb) info threads
Id Target Id Frame
*1 Thread 1 (CPU#0 [halted ]) cpu_v7_do_idle () at /home/lkd/sources/linux/arch/arm/mm/proc-v7.S:74
2 Thread 2 (CPU#1 [halted ]) cpu_v7_do_idle () at /home/lkd/sources/linux/arch/arm/mm/proc-v7.S:74
(gdb) bt
#0 cpu_v7_do_idle () at /home/lkd/sources/linux/arch/arm/mm/proc-v7.S:74
#1 0xc0308728 in arch_cpu_idle () at /home/lkd/sources/linux/arch/arm/kernel/process.c:72
#2 0xc0376b28 in cpuidle_idle_call () at /home/lkd/sources/linux/kernel/sched/idle.c:151
#3 cpu_idle_loop () at /home/lkd/sources/linux/kernel/sched/idle.c:242
#4 cpu_startup_entry (state=<optimized out>) at /home/lkd/sources/linux/kernel/sched/idle.c:291
#5 0xc0ae8a30 in rest_init () at /home/lkd/sources/linux/init/main.c:408
#6 0xc0f00c5c in start_kernel () at /home/lkd/sources/linux/init/main.c:661
Targets : Qemu (Example)
qemu-system-arm -kernel ./zImage -dtb ./vexpress-v2p-ca15-tc1.dtb -M vexpress-a15 -smp 2 -m 1024 -append 'root=/dev/nfs nfsroot=10.0.2.2:/opt/root/armv7/,tcp,v3 rw
ip=dhcp mem=1024M raid=noautodetect rootwait console=ttyAMA0,38400n8 devtmpfs.mount=0' -nographic -gdb tcp::32770
[ 0.000000] Booting Linux on physical CPU 0x0
[ 0.000000] Linux version 4.6.0-rc1 (kbingham@CookieMonster) (gcc version 5.2.1 20151010 (Ubuntu 5.2.1-22ubuntu1) ) #13 SMP Thu Mar 31 10:33:19 BST 2016
[ 0.000000] CPU: ARMv7 Processor [412fc0f1] revision 1 (ARMv7), cr=10c5387d
[ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache
[ 0.000000] Machine model: V2P-CA15
[ ….. ]
[ 3.989042] IP-Config: Got DHCP answer from 10.0.2.2, my address is 10.0.2.15
[ 3.991451] IP-Config: Complete:
[ 3.991672] device=eth0, hwaddr=52:54:00:12:34:56, ipaddr=10.0.2.15, mask=255.255.255.0, gw=10.0.2.2
[ QEmu is a user
3.991900] process
host=10.0.2.15, trying
domain=, to mount NFS on ports above 1024
nis-domain=(none)
[ 3.992039] bootserver=10.0.2.2, rootserver=10.0.2.2, rootpath= nameserver0=10.0.2.3
This isn’t allowed by default, so we need to add the ‘insecure’ option
$ cat./linux/vmlinux
arm-linux-gdb /etc/exports -iex 'add-auto-load-safe-path ./linux' -ex 'target remote localhost:32770'
Remote debugging using localhost:32770
/opt/rootfs
cpu_v7_do_idle *(rw,sync,no_subtree_check,no_root_squash,insecure)
() at /home/lkd/sources/linux/arch/arm/mm/proc-v7.S:74
74 ret lr
(gdb) info threads
Id Target Id Frame
*1 Thread 1 (CPU#0 [halted ]) cpu_v7_do_idle () at /home/lkd/sources/linux/arch/arm/mm/proc-v7.S:74
2 Thread 2 (CPU#1 [halted ]) cpu_v7_do_idle () at /home/lkd/sources/linux/arch/arm/mm/proc-v7.S:74
(gdb) bt
#0 cpu_v7_do_idle () at /home/lkd/sources/linux/arch/arm/mm/proc-v7.S:74
#1 0xc0308728 in arch_cpu_idle () at /home/lkd/sources/linux/arch/arm/kernel/process.c:72
#2 0xc0376b28 in cpuidle_idle_call () at /home/lkd/sources/linux/kernel/sched/idle.c:151
#3 cpu_idle_loop () at /home/lkd/sources/linux/kernel/sched/idle.c:242
#4 cpu_startup_entry (state=<optimized out>) at /home/lkd/sources/linux/kernel/sched/idle.c:291
#5 0xc0ae8a30 in rest_init () at /home/lkd/sources/linux/init/main.c:408
#6 0xc0f00c5c in start_kernel () at /home/lkd/sources/linux/init/main.c:661
Targets: JTAG
+ OpenOCD is open source
+ Supports gdbremote protocol
+ Supports many ARM/MIPS CPUs
+ Supports many FTDI based JTAG
probes http://openocd.org
http://elinux.org/JTAG
Host
OpenOCD Target System
Telnet telnet
JTAG JTAG
GDB Client gdbserver
Targets: Core Dumps
● CONFIG_PROC_KCORE
○ sudo gdb vmlinux /proc/kcore
○ Virtual ELF core file of live kernel
○ No modifications can be made
● CONFIG_PROC_VMCORE
○ /proc/vmcore
○ Used in conjunction with kexec, kdump
and the crash utility from RedHat
○ py-crash, and libkdumpfile support
coming to GDB from SUSE https://en.wikipedia.org/wiki/Kdump_(Linux) @V4711
https://www.suse.com/documentation/sles-12/book_sle_tuning/data/part_tuning_dumps.html
Linux Awareness
● Provide the debugger with additional knowledge of the underlying
operating system to enable a better debugging experience.
○ Where is the Task List?
○ What is in the Kernel Log Buffer?
○ What modules are loaded? Where?
● We split Linux Awareness into three areas
1. Task Awareness
● Ability to report all task_structs as threads in GDB
● Provides selectable GDB threads with context commands
2. Loadable Module Support
● Hooks for automatic symbol resolution when modules are inserted
3. OS Helper Commands
● Interacting with the debugger to obtain useful information
GDB C Extension - Linux Kernel Debugger (LKD)
● Original tools written at ST Micro provide
“Linux Awareness”
● ST-LKD based on GDB 7.6
● Developed for STMC2 JTAG debugger
● Upstream project started by
Peter Griffin, supported by ST
and Linaro
Where to put the ‘awareness’
1. Scripting in GDB (Python/Guile)
2. C extension in GDB
3. Awareness in GDB Stub
Linux Source 1
Python Plugin 2 gdbremote
3
GDB Stub
GDB Client
Kgdb / OpenOCD
Guile Plugin
Kernel Awareness
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Linux Source
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Lin
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KGDB
Ta
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GDB Client
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QEmu/KVM | JTAG Remote | Core Dump
LKD-C vs LKD-Python
LKD-C LKD-Python
+ Reference code available + Awareness lives in source tree
+ Working now + Generic approach for other OS’s
+ Or languages ….
- Puts Linux specific code into - gdb.Target layer exposes gdb
GDB internal hooks to the outside
- Must be robust!
Thread Awareness : GDB Target Implementation
static struct target_ops * linux_kthread_target (void)
{
struct target_ops *t = XCNEW (struct target_ops);
t->to_shortname = "linux-kthreads";
t->to_longname = "linux kernel-level threads";
t->to_doc = "Linux kernel-level threads"; LKD-C
t->to_close = linux_kthread_close;
t->to_mourn_inferior = linux_kthread_mourn_inferior;
t->to_fetch_registers = linux_kthread_fetch_registers;
t->to_store_registers = linux_kthread_store_registers;
t->to_wait = linux_kthread_wait;
t->to_resume = linux_kthread_resume;
t->to_thread_alive = linux_kthread_thread_alive;
t->to_update_thread_list = linux_kthread_update_thread_list;
t->to_extra_thread_info = linux_kthread_extra_thread_info;
t->to_pid_to_str = linux_kthread_pid_to_str;
t->to_stratum = thread_stratum;
t->to_magic = OPS_MAGIC;
return t;
}
Task Awareness
qemu-system-arm -kernel ./zImage -dtb ./vexpress-v2p-ca15-tc1.dtb -M vexpress-a15 -smp 2 -m 1024 -append 'root=/dev/nfs nfsroot=10.0.2.2:/opt/root/armv7/,tcp,v3 rw
ip=dhcp mem=1024M raid=noautodetect rootwait console=ttyAMA0,38400n8 devtmpfs.mount=0' -nographic -gdb tcp::32770
[ 0.000000] Booting Linux on physical CPU 0x0
[ 0.000000] Linux version 4.6.0-rc1 (kbingham@CookieMonster) (gcc version 5.2.1 20151010 (Ubuntu 5.2.1-22ubuntu1) ) #13 SMP Thu Mar 31 10:33:19 BST 2016
[ 0.000000] CPU: ARMv7 Processor [412fc0f1] revision 1 (ARMv7), cr=10c5387d
[ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache
[ 0.000000] Machine model: V2P-CA15
[ ….. ]
threads now
appear in the
lkd/bin/arm-linux-gdb ./linux/vmlinux -iex 'add-auto-load-safe-path ./linux' -ex 'target remote localhost:32770'
Remote debugging using localhost:32770 inferior
(gdb) info threads
Id Target Id Frame
*1 [swapper/0] (TGID:0 <C0>) cpu_v7_do_idle () at ../linux/arch/arm/mm/proc-v7.S:74
2 [swapper/1] (TGID:0 <C1>) cpu_v7_do_idle () at ../linux/arch/arm/mm/proc-v7.S:74
3 init (TGID:1) context_switch (next=<optimized out>, prev=<optimized out>, rq=<optimized out>) at ../linux/kernel/sched/core.c:2734
4 [kthreadd] (TGID:2) context_switch (next=<optimized out>, prev=<optimized out>, rq=<optimized out>) at ../linux/kernel/sched/core.c:2734
5 [ksoftirqd/0] (TGID:3) context_switch (next=<optimized out>, prev=<optimized out>, rq=<optimized out>) at ../linux/kernel/sched/core.c:2734
6 [kworker/u4:0] (TGID:6) context_switch (next=<optimized out>, prev=<optimized out>, rq=<optimized out>) at ../linux/kernel/sched/core.c:2734
7 [rcu_sched] (TGID:7) context_switch (next=<optimized out>, prev=<optimized out>, rq=<optimized out>) at ../linux/kernel/sched/core.c:2734
8 [rcu_bh] (TGID:8) context_switch (next=<optimized out>, prev=<optimized out>, rq=<optimized out>) at ../linux/kernel/sched/core.c:2734
9 [migration/0] (TGID:9) context_switch (next=<optimized out>, prev=<optimized out>, rq=<optimized out>) at ../linux/kernel/sched/core.c:2734
10 [watchdog/0] (TGID:10) context_switch (next=<optimized out>, prev=<optimized out>, rq=<optimized out>) at ../linux/kernel/sched/core.c:2734
11 [cpuhp/0] (TGID:11) context_switch (next=<optimized out>, prev=<optimized out>, rq=<optimized out>) at ../linux/kernel/sched/core.c:2734
[...]
Extending GDB with Python
● Commands
● Functions
● Pretty Printing objects
● Frame Filters / Unwinders
● Breakpoints
● … and more ...
https://sourceware.org/gdb/onlinedocs/gdb/Python-API.html
Thread awareness in Python
def to_update_thread_list(self):
inferior = gdb.selected_inferior() LKD-Python
threads = inferior.threads()
for task in tasks.task_lists():
ptid = [inferior.pid, int(task['pid']), 0] # (pid, lwp, tid)
if ptid not in threads:
thread = inferior.new_thread(ptid, task)
thread.name = task['comm'].string()
# Provide thread registers for backtrace
self.setup_threads(thread, task)
Module Symbol support
(gdb) lx-symbols /opt/rootfs/armv7/lib/modules/4.6.0-rc1/
loading vmlinux
(gdb) c
Continuing.
root@10.0.2.15:~# depmod -a
[ 63.643135] random: nonblocking pool is initialized
root@10.0.2.15:~# modprobe helloworld
WARNING: All config files need .conf: /etc/modprobe.
d/invalid, it will be ignored in a future release.
scanning for modules in /opt/root/armv7/lib/modules/4.6.0-
rc1/
scanning for modules in /home/lkd/targets/qemu-arm
loading @0xbf000000: ../lib/modules/4.6.0-
rc1/extra/helloworld.ko
[ 73.866004] <1>Hello World 0 !
[ 73.893862] Wow... kernel level thread saying hello :) : 0
[ 73.924062] Wow... kernel level thread saying hello :) : 1
[ 73.952099] Wow... kernel level thread saying hello :) : 2
Linux GDB extensions in v4.6-rc1
(gdb) apropos lx
function lx_current -- Return current task
function lx_module -- Find module by name and return the module variable
function lx_per_cpu -- Return per-cpu variable
function lx_task_by_pid -- Find Linux task by PID and return the task_struct variable
function lx_thread_info -- Calculate Linux thread_info from task variable
lx-cmdline -- Report the Linux Commandline used in the current kernel
lx-dmesg -- Print Linux kernel log buffer
lx-list-check -- Verify a list consistency
lx-lsmod -- List currently loaded modules
lx-ps -- Dump Linux tasks
lx-symbols -- (Re-)load symbols of Linux kernel and currently loaded modules
lx-version -- Report the Linux Version of the current kernel
Extending GDB with Python
gdb.Command : lx-cmdline
class LxCmdLine(gdb.Command):
""" Report the Linux Commandline used in the current kernel.
Equivalent to cat /proc/cmdline on a running target"""
def __init__(self):
super(LxCmdLine, self).__init__("lx-cmdline", gdb.COMMAND_DATA)
def invoke(self, arg, from_tty):
gdb.write(gdb.parse_and_eval("saved_command_line").string() + "\n")
LxCmdLine()
Extending GDB with Python
gdb.Command : lx-cmdline
class LxCmdLine(gdb.Command):
""" Report the Linux Commandline used in the current kernel.
(gdb) lx-cmdline
Equivalent to cat /proc/cmdline on a running target"""
root=/dev/nfs nfsroot=10.0.2.2:/opt/root/armv7/,tcp,v3 rw ip=dhcp mem=1024M
raid=noautodetect rootwait console=ttyAMA0,38400n8 devtmpfs.mount=0
def __init__(self):
super(LxCmdLine, self).__init__("lx-cmdline", gdb.COMMAND_DATA)
(gdb) help lx-cmdline
Report the Linux Commandline used in the current kernel.
Equivalent to catarg,
def invoke(self, /proc/cmdline
from_tty): on a running target
gdb.write(gdb.parse_and_eval("saved_command_line").string() + "\n")
LxCmdLine()
Extending GDB with Python
gdb.Function : lx_task_by_pid
class LxTaskByPidFunc(gdb.Function):
"""Find Linux task by PID and return the task_struct variable.
$lx_task_by_pid(PID): Given PID, iterate over all tasks of the target and
return that task_struct variable which PID matches."""
def __init__(self):
super(LxTaskByPidFunc, self).__init__("lx_task_by_pid")
def invoke(self, pid):
task = get_task_by_pid(pid)
if task:
return task.dereference()
else:
raise gdb.GdbError("No task of PID " + str(pid))
LxTaskByPidFunc()
Extending GDB with Python
gdb.Function : lx_task_by_pid
class LxTaskByPidFunc(gdb.Function):
"""Find Linux task by PID and return the task_struct variable.
$lx_task_by_pid(PID): Given PID, iterate over all tasks of the target and
return that task_struct variable which PID matches."""
(gdb) lx-ps
0xeeea5500 1163 lircd
def __init__(self): ## Output trimmed ….
super(LxTaskByPidFunc, self).__init__("lx_task_by_pid")
(gdb) set $task = $lx_task_by_pid(1163)
(gdb) print $task.comm
def invoke(self, pid):
task = get_task_by_pid(pid)
$5 = "lircd\000" if task:
(gdb) print $task.return <tab task.dereference()
completion available>
else:
raise gdb.GdbError("No task of PID " + str(pid))
LxTaskByPidFunc()
Extending GDB with Python
gdb.Function : lx_radix_tree_lookup (not in ML)
(gdb)class
print LxRadixTree(gdb.Function):
irq_desc_tree
""" Lookup and return a node from a RadixTree.
$1 = {
$lx_radix_tree_lookup(root_node [, index]): Return the node at the given index.
height = 1,
If index is omitted, the root node is dereferenced and returned."""
gfp_mask = 37748928,
def __init__(self):
rnode = 0xee000001 super(LxRadixTree, self).__init__("lx_radix_tree_lookup")
}
def invoke(self, root, index=0):
(gdb) print *irq_desc_tree.rnode
result = lookup(root, index)
$2 = { if result is None:
raise gdb.GdbError("No entry in tree at index {}".format(index))
path = 855638016,
count = 0, return result
…. LxRadixTree()
slots = {0xc0ee8030, 0x80ee8030, 0x40ee8031, 0xee8032, 0xc0ee8033, …...
Extending GDB with Python
gdb.Function : lx_radix_tree_lookup (not in ML)
class LxRadixTree(gdb.Function):
""" Lookup and return a node from a RadixTree.
$lx_radix_tree_lookup(root_node [, index]): Return the node at the given index.
If index is omitted, the root node is dereferenced and returned."""
def __init__(self):
super(LxRadixTree, self).__init__("lx_radix_tree_lookup")
def invoke(self, root, index=0):
result = lookup(root, index)
if result is None:
raise gdb.GdbError("No entry in tree at index {}".format(index))
return result
LxRadixTree()
[PATCHv4 10/12] scripts/gdb: Add a Radix Tree Parser
https://lkml.org/lkml/2016/3/30/277
Extending GDB with Python
gdb.Function : lx_radix_tree_lookup (not in ML)
class LxRadixTree(gdb.Function):
""" Lookup
(gdb) print and return
((struct a node from a RadixTree.
irq_desc)$lx_radix_tree_lookup(irq_desc_tree, 18)).irq_data
$3 = $lx_radix_tree_lookup(root_node
{ [, index]): Return the node at the given index.
maskIf index
= 0,is omitted, the root node is dereferenced and returned."""
irq = 18,
def __init__(self):
hwirq = 27, super(LxRadixTree, self).__init__("lx_radix_tree_lookup")
common = 0xee803d80,
def invoke(self, root, index=0):
result = lookup(root, index)
chip = 0xc100285c <gic_data>,
if result is None:
domain = 0xee808000, raise gdb.GdbError("No entry in tree at index {}".format(index))
parent_data = return 0x0,result
chip_data = 0xc100285c <gic_data>
LxRadixTree()
}
Extending GDB with Python : Accessing data
● GDB provides accessors to read memory
def module_list():
modules = gdb.parse_and_eval("modules")
entry = modules['next']
end_of_list = modules.address
● Reading structures is ‘easy’
for vfs in lists.list_for_each_entry(namespace['list'],mount_ptr_type, "mnt_list"):
devname = vfs['mnt_devname'].string()
superblock = vfs['mnt']['mnt_sb']
fstype = superblock['s_type']['name'].string()
s_flags = int(superblock['s_flags'])
m_flags = int(vfs['mnt']['mnt_flags'])
● Complicated data structures can be programmed
Python Extension Summary
● Easy to write your own commands / plugins to GDB
● Docstring as Documentation
● Accessing data in Python is easy
○ Structures organised as python dictionaries
○ Pointers automatically dereferenced
What’s Next
● Automated regression testing
○ LAVA / KernelCI ...
● Continue upstream push of thread awareness
○ C / Python / Javascript
And then ?
● IDE integration
● Userspace debug extensions?
● Page table walks?
● The world ...
Summary
Targets Kernel Awareness
● KGDB ● Thread Awareness
○ In kernel debugging ○ In Progress!
● QEmu / KVM / UML ● Module support
○ Virtualized environments ○ Mostly there
● JTAG ● Data Retrieval
○ Real Hardware ○ Commands available
● Core Dumps ● Oysters or Pythons?
○ Real problems ○ The world is your ...
Some references / Credits
● Linaro
○ http://www.linaro.org
● O’Rly Images
○ Buy the T-Shirts @ https://threddit.com/ThePracticalDev
● GDB Python API Documentation
○ https://sourceware.org/gdb/onlinedocs/gdb/Python-API.html
● Me
○ http://www.kieranbingham.co.uk
Slides should be available on ELC website, or from my Blog URL
Code/GIT URL’s
● [PATCHv4 00/12] gdb/scripts: Linux awareness debug commands
○ https://lkml.org/lkml/2016/3/30/269
● Linux
○ https://git.linaro.org/people/kieran.bingham/linux.git
■ Tag: gdb-scripts-v4 - Latest submission
■ Branch: gdb-scripts - All work including experimental linux-awareness.py
● Binutils-GDB :
○ https://git.linaro.org/people/kieran.bingham/binutils-gdb.git/
■ Branch: lkd-thread-aware-c - Working version of thread awareness
■ Branch: linux-kthreads - Work in progress - C implementation for upstream
■ Branch: lkd-python - Experimental - Python gdb.Target
● Qemu Quickstart (to try thread awareness, using lkd-thread-aware-c)
○ git clone https://git.linaro.org/people/kieran.bingham/qemu-kernel.git
○ Make # builds kernel, and binutils-gdb
○ Terminal 1: make qemu-run | Terminal 2: make qemu-gdb
Q+A?
