Messages in this thread | | | Date | Wed, 4 Feb 2015 11:48:43 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 1/1] futex: check PF_KTHREAD rather than !p->mm to filter out kthreads |
| |
On Mon, Feb 02, 2015 at 03:05:36PM +0100, Oleg Nesterov wrote: > attach_to_pi_owner() checks p->mm to prevent attaching to kthreads and > this looks doubly wrong: > > 1. It should actually check PF_KTHREAD, kthread can do use_mm(). > > 2. If this task is not kthread and it is actually the lock owner we can > wrongly return -EPERM instead of -ESRCH or retry-if-EAGAIN. > > And note that this wrong EPERM is the likely case unless the exiting > task is (auto)reaped quickly, we check ->mm before PF_EXITING. > > Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
| |