Acquiring a mtx after an sx lock

[Max Laier]

On Monday 18 August 2008 17:14:01 Ryan Stone wrote:
> Are there any problems acquiring a sleep mutex after acquiring an sx lock?
> man 9 locking says that you can't, but doesn't provide any reasons.
> Obviously while you're holding the mutex you have to abide by the rules
> applying to mutexes, but as long as you do that, I can't see why acquiring
> a mutex after an sx lock would cause an issue.  Is the locking man page
> wrong about this?

Where does it say so?  The interaction table clearly shows:

      You have: You want:  Spin_mtx  Slp_mtx sx_lock rw_lock rm_locksleep
      SPIN mutex           ok-1      no      no      no      no    no-3
      Sleep mutex          ok        ok-1    no      ok      ok    no-3
                                      |
                                      V
      sx_lock              ok     -->ok<--   ok-2    ok      ok    ok-4
                                      ^
                                      |
      rw_lock              ok        ok      no      ok-2    ok    no-3
      rm_lock              ok        ok      no      ok      ok-2  no


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