Re: [PATCH bpf-next 0/3] Always allow sleepable and fmod_ret programs on syscalls

[Leon Hwang <leon.hwang@linux.dev>]

On 6/3/26 10:14, Kumar Kartikeya Dwivedi wrote:
> On Fri, 6 Mar 2026 at 03:04, Leon Hwang <leon.hwang@linux.dev> wrote:
>>
>> Hi Viktor,
>>
>> On 5/3/26 23:25, Viktor Malik wrote:
>>> Both sleepable and fmod_ret programs are only allowed on selected
>>> functions. For convenience, the error injection list was originally
>>> used.
>>>
>>> When error injection is disabled, that list is empty and sleepable
>>> tracing programs, as well as fmod_ret programs, are effectively
>>> unavailable.
>>>
>>> This patch series addresses the issue by at least enabling sleepable and
>>> fmod_ret programs on syscalls, if error injection is disabled.
>>>
>>
>> Could you please explain more about the purpose in cover letter?
>>
>> I'm curious about enabling fmod_ret programs on syscalls, as they are
>> able to modify the retval of syscalls.
> 
> It was already discussed at length here:
> https://lore.kernel.org/bpf/CAADnVQJ4PU7bCb5XO9+zMZhLRSdbCKwxG6Rtojh2Rc3UZ8H43Q@mail.gmail.com/
> 

Thanks for pointing this out.

Thanks,
Leon

> I think the next version could include a link to the previous thread
> in the cover letter for posterity.
> 
>>
>> Thanks,
>> Leon
>>
>>> Viktor Malik (3):
>>>   bpf: Always allow sleepable programs on syscalls
>>>   bpf: Always allow fmod_ret programs on syscalls
>>>   selftests/bpf: Move sleepable refcounted_kptr tests to syscalls
>>>
>>>  kernel/bpf/verifier.c                         | 79 +++++++++++++++----
>>>  .../selftests/bpf/progs/refcounted_kptr.c     |  4 +-
>>>  .../bpf/progs/refcounted_kptr_fail.c          |  2 +-
>>>  3 files changed, 68 insertions(+), 17 deletions(-)
>>>
>>
>>