cvs commit: src/sys/vm vm_object.c

[Alan Cox]

alc         2006-07-17 06:45:03 UTC

  FreeBSD src repository

  Modified files:
    sys/vm               vm_object.c 
  Log:
  Ensure that vm_object_deallocate() doesn't dereference a stale object
  pointer: When vm_object_deallocate() sleeps because of a non-zero
  paging in progress count on either object or object's shadow,
  vm_object_deallocate() must ensure that object is still the shadow's
  backing object when it reawakens.  In fact, object may have been
  deallocated while vm_object_deallocate() slept.  If so, reacquiring
  the lock on object can lead to a deadlock.
  
  Submitted by: ups@
  MFC after: 3 weeks
  
  Revision  Changes    Path
  1.360     +13 -6     src/sys/vm/vm_object.c