Re: Patch to lock down modules

On Thu, 14 Mar 2002, Jake Burkholder wrote:

:
:Couple problems:
:
:I think that you missed a MOD_SLOCK before the
:	newmod = module_lookupbyname(data->name);
:in module_register.

Actually, iirc, module_register only got called from one spot, and in that
spot, keeping SLOCK held seemed better than dropping it and reaquiring a
SLOCK in module_register.  If we'd like to keep this more consisten with
some of the other funcitons, then I can change this no problem.

:
:Also in that function the MOD_XLOCK isn't needed until just before the
:TAILQ_INSERT_TAIL.  The increment of nextid needs something, I would
:probably move it to just before the TAILQ_INSERT, under the XLOCK.  An
:atomic_add_and_return_old_value would be useful here.  Also, I think
:that you should do another module_lookupbyname after acquiring the
:XLOCK and before the TAILQ_INSERT, because conceivably another module
:with the same name could show up when you release the SLOCK.

Seems reasonable...

:Can you explain the wierd logic that was added to linker_file_unload?

Ugh, yes, this is kinda ugly.  Essentially this is a result of hacking
this back and forth between where we should be holding SLOCK over.  This
is exactly what I wanted to discuss this b/c prior to making this change,
I had a much more simple strategy here (but was dropped due to changes to
a better strategy for kern_module).  We discussed before about possibly
having two sets of lookup functions -- internal and external -- perhaps
this is a better solution?  

:Thanks,
:Jake
:

--
Andrew R. Reiter
[e-mail]
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