kernel thread as real threads..

M. Warner Losh imp at
Mon Jan 23 19:04:18 PST 2006

In message: <Pine.GSO.4.43.0601231954150.17167-100000 at>
            Daniel Eischen <deischen at> writes:
: On Mon, 23 Jan 2006, Julian Elischer wrote:
: > Robert Watson wrote:
: >
: >
: > well, the operation woudll continue for the parent only I woudl assume.
: >
: > > (although davidxu is changing that)
: >
: > I'm not convinced that that multiple threads should be allowed to
: > proceed during a fork
: > but I can see that not allowing it is more a "foot shooting avoidance"
: > than a requirement.
: > it could be allowed that if you do a fork and allow multipel threads to
: > runat the same time
: > and end up with an inconsistant address space in the child, then you get
: > what you deserve.
: > :-)
: POSIX specifies that only 1 thread (the forking thread) is present
: after a fork.  If you want all (or some subset) of the parent's
: threads to exist after a fork(), you must call it something
: else (use a flag to rfork?) and ensure it is not the default
: behavior.

The problem that we have today is that single_thread suspends most,
but not all, of the threads.  There are many scenarios where one could
get deadlock if you are sleeping uninterruptably in one thread, but
interruptably in another.


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