Why need a lock in memory/capability map

Adam Lackorzynski adam at os.inf.tu-dresden.de
Sun Jul 20 23:34:12 CEST 2014

On Fri Jul 18, 2014 at 18:34:31 -0400, Yuxin Ren wrote:
> I note that when a thread does memory or capability mapping, both over
> system call and IPC, it needs take a lock, which is the existence_lock of
> target task. I cannot understand it needs take a per task, as cap/page
> table are per thread.
> What data does this lock to protect?

Memory as well as caps are per task, so the lock makes sure that the
task does not disappear while an operation is in progress.

Adam                 adam at os.inf.tu-dresden.de
  Lackorzynski         http://os.inf.tu-dresden.de/~adam/

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