Re: Subtle MM bug

Stephen C. Tweedie (sct@redhat.com)
Thu, 11 Jan 2001 14:13:30 +0000


Hi,

On Thu, Jan 11, 2001 at 02:12:05PM +0100, Trond Myklebust wrote:
>
> What's wrong with copy-on-write style semantics? IOW, anyone who
> wants to change the credentials needs to make a private copy of the
> existing structure first.

Because COW only solves the problem if each task is only changing its
own, local, private copy of the credentials. Posix threads demand
that one thread changing credentials also affects all the other
threads immediately, and making your own local private copy won't help
you to change the other tasks' credentials safely.

--Stephen
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