Re: [External] Re: BPF fentry/fexit trampolines stall livepatch stalls transition due to missing ORC unwind metadata

[Andrey Grodzovsky <andrey.grodzovsky@crowdstrike.com>]

On 11/24/25 19:06, Josh Poimboeuf wrote:
> On Mon, Nov 24, 2025 at 05:54:15PM -0500, Andrey Grodzovsky wrote:
>> On 11/24/25 17:51, Josh Poimboeuf wrote:
>>> On Mon, Nov 24, 2025 at 05:06:04PM -0500, Andrey Grodzovsky wrote:
>>>>> Andrey, can you try this patch?
>>>>
>>>> Hey Josh, thank you for looking, can you please advise the stable
>>>> kernel version you have made this changes on top off so I can cleanly
>>>> apply ? Alternatively just provide git commit sha in Linus
>>>> tree I can reset my branch to.
>>>>
>>>>
>>>> I will happily test this as soon as I can and report back.
>>>
>>> It's based on Linus's tree.
>>>
>>
>> Latest more or less ?
> 
> Yes, it still applies to his latest master (v6.18-rc7).
> 

Tested, looks good.

kernel as above, before patch application dmesg

ubuntu-24-04@ubuntu-24-04:~/livepatch-bpf-test$ sudo insmod 
livepatches/livepatch_cmdline_test.ko
ubuntu-24-04@ubuntu-24-04:~/livepatch-bpf-test$ sudo dmesg -w
[  128.434944] livepatch_cmdline_test: loading out-of-tree module taints 
kernel.
[  128.434955] livepatch_cmdline_test: tainting kernel with TAINT_LIVEPATCH
[  128.434958] livepatch_cmdline_test: module verification failed: 
signature and/or required key missing - tainting kernel
[  128.435579] livepatch_cmdline_test: initializing
[  128.435640] livepatch: enabling patch 'livepatch_cmdline_test'
[  128.435643] livepatch: 'livepatch_cmdline_test': initializing 
patching transition
[  128.439051] livepatch: 'livepatch_cmdline_test': starting patching 
transition
[  128.439982] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  128.440028] livepatch: klp_try_switch_task: swapper/0:0 is running
[  128.440041] livepatch: klp_try_switch_task: swapper/1:0 is running
[  128.440051] livepatch: klp_try_switch_task: swapper/3:0 is running
[  128.440060] livepatch: klp_try_switch_task: swapper/4:0 is running
[  128.440069] livepatch: klp_try_switch_task: swapper/5:0 is running
[  128.440078] livepatch: klp_try_switch_task: swapper/6:0 is running
[  128.440090] livepatch: klp_try_switch_task: swapper/7:0 is running
[  128.440099] livepatch: klp_try_switch_task: swapper/8:0 is running
[  128.440125] livepatch: klp_try_switch_task: swapper/9:0 is running
[  128.440138] livepatch: klp_try_switch_task: swapper/12:0 is running
[  128.440147] livepatch: klp_try_switch_task: swapper/13:0 is running
[  128.440161] livepatch_cmdline_test: patch enabled successfully
[  129.586202] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  130.651011] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  131.595098] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  132.910147] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  134.578055] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  135.613832] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  136.646585] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  137.589959] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  138.607729] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  139.570125] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  140.601715] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  141.643745] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  142.595307] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  143.605116] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  144.628517] livepatch: klp_try_switch_task: tcp_recv_hang:1219 has an 
unreliable stack
[  144.628544] livepatch: signaling remaining tasks
[  145.611813] livepatch: 'livepatch_cmdline_test': completing patching 
transition
[  145.612271] livepatch: 'livepatch_cmdline_test': patching complete

After patch application -

ubuntu-24-04@ubuntu-24-04:~$ sudo insmod 
livepatches/livepatc^Ccmdline_test.ko
ubuntu-24-04@ubuntu-24-04:~$ cd livepatch-bpf-test/
ubuntu-24-04@ubuntu-24-04:~/livepatch-bpf-test$ sudo insmod 
livepatches/livepatch_cmdline_test.ko
ubuntu-24-04@ubuntu-24-04:~/livepatch-bpf-test$ sudo dmesg -dw
[  270.168371 <    0.000000>] livepatch_cmdline_test: loading 
out-of-tree module taints kernel.
[  270.168386 <    0.000015>] livepatch_cmdline_test: tainting kernel 
with TAINT_LIVEPATCH
[  270.168389 <    0.000003>] livepatch_cmdline_test: module 
verification failed: signature and/or required key missing - tainting kernel
[  270.169202 <    0.000813>] livepatch_cmdline_test: initializing
[  270.169260 <    0.000058>] livepatch: enabling patch 
'livepatch_cmdline_test'
[  270.169262 <    0.000002>] livepatch: 'livepatch_cmdline_test': 
initializing patching transition
[  270.171969 <    0.002707>] livepatch: 'livepatch_cmdline_test': 
starting patching transition
[  270.172892 <    0.000923>] livepatch: klp_try_switch_task: 
swapper/0:0 is running
[  270.172904 <    0.000012>] livepatch: klp_try_switch_task: 
swapper/2:0 is running
[  270.172912 <    0.000008>] livepatch: klp_try_switch_task: 
swapper/4:0 is running
[  270.172920 <    0.000008>] livepatch: klp_try_switch_task: 
swapper/5:0 is running
[  270.172927 <    0.000007>] livepatch: klp_try_switch_task: 
swapper/7:0 is running
[  270.172935 <    0.000008>] livepatch: klp_try_switch_task: 
swapper/8:0 is running
[  270.172942 <    0.000007>] livepatch: klp_try_switch_task: 
swapper/9:0 is running
[  270.172954 <    0.000012>] livepatch: klp_try_switch_task: 
swapper/10:0 is running
[  270.172959 <    0.000005>] livepatch: klp_try_switch_task: 
swapper/11:0 is running
[  270.172966 <    0.000007>] livepatch: klp_try_switch_task: 
swapper/13:0 is running
[  270.172971 <    0.000005>] livepatch_cmdline_test: patch enabled 
successfully
[  271.008394 <    0.835423>] livepatch: 'livepatch_cmdline_test': 
completing patching transition
[  271.009156 <    0.000762>] livepatch: 'livepatch_cmdline_test': 
patching complete


ubuntu-24-04@ubuntu-24-04:~/livepatch-bpf-test$ sudo cat /proc/kallsyms 
| grep cmdline_proc_show
ffffffffb4a55c20 t __pfx_cmdline_proc_show
ffffffffb4a55c30 t cmdline_proc_show
ffffffffc09300b0 t livepatch_cmdline_proc_show	[livepatch_cmdline_test]
ffffffffc09300a0 t __pfx_livepatch_cmdline_proc_show 
[livepatch_cmdline_test]
ubuntu-24-04@ubuntu-24-04:~/livepatch-bpf-test$


Andrey