cvs commit: src/sys/kern kern_sysctl.c

[John Baldwin]

On 29-May-2003 Maxime Henrion wrote:
> Nate Lawson wrote:
>> On Thu, 29 May 2003, Maxime Henrion wrote:
>> >   Modified files:
>> >     sys/kern             kern_sysctl.c
>> >   Log:
>> >   When loading a module that contains a sysctl which is already compiled
>> >   in the kernel, the sysctl_register() call would fail, as expected.
>> >   However, when unloading this module again, the kernel would then panic
>> >   in sysctl_unregister().  Print a message error instead.
>> >
>> > +  /*
>> > +   * This can happen when a module fails to register and is
>> > +   * being unloaded afterwards.  It should not be a panic()
>> > +   * for normal use.
>> > +   */
>> > +  if (error)
>> > +          printf("%s: failed to unregister sysctl\n", __func__);
>> 
>> Thank you, this is helpful.  However, we have quite a few error messages
>> that appear when an attach fails.  Is this one necessary in practice or
>> should the eventual plan be to change the API to return an errno?  (Note,
>> not talking about 5.1 here).
> 
> I agree with you that we should think about this issue a bit more once
> 5.1 is out, as I'm not comfortable with this error message.  However, if
> I remember right, changing the API is not an option after 5.1 since we
> promised to not break APIs and ABIs past this release.  If the message
> turns out to be annoying, it can be removed a bit later and we can have
> sysctl_unregister() silently fail.  Changing the API would probably be
> better, but I bet we'll have to do this for 6.0.

AFAIK, the API and ABI is not frozen until RELENG_5 is branched.
That isn't happening at 5.1 release, so there is still some time to
fix the API/ABI if need be.  We really should start avoiding making
API/ABI changes though after 5.1 is out.

-- 

John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/