Re: uselib() & 2.6.X?

From: Linus Torvalds
Date: Sat Jan 08 2005 - 20:41:43 EST




On Sat, 8 Jan 2005, Marcelo Tosatti wrote:
>
> > No, I'd just fix them up.
>
> What do you mean by "fix them up" ? With your minimal fix the other do_brk() callers
> do not have the lock, you dont mean "fix" by grabbing the lock?

I'm saying that if we decide to do the debugging warning (and I think
everybody is agreeing that we should), then we _will_ fix it by just
grabbing the lock in all the paths. That's what we already did with
do_mmap(), after all.

I suspect it's not strictly needed, but as Alan has said, even though
nothing else can chaneg the vma's at the same time, it's the right thing
to do to keep /proc reads happy (which _can_ happen) anyway. And more
importantly, invariants are nice - to the point where it's good to follow
the rules even if it might not be strictly necessary.

I just wanted to keep these two issues separate. I think it's one thing to
fix a known bug, and another thing to add some debug infrastructure to
make sure that it doesn't happen in the future. So I think the WARN_ON() +
adding of extra locking is a separate stage from fixing the known problem.

Linus
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