Commit f7505d64 authored May 31, 2012 by Konstantin Khlebnikov Committed by Linus Torvalds May 31, 2012

fork: call complete_vfork_done() after clearing child_tid and flushing rss-counters

Child should wake up the parent from vfork() only after finishing all
operations with shared mm.  There is no sense in using
CLONE_CHILD_CLEARTID together with CLONE_VFORK, but it looks more accurate
now.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent bca15543

kernel/fork.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -787,9 +787,6 @@ void mm_release(struct task_struct tsk, struct mm_struct mm)
		/* Get rid of any cached register state */
		deactivate_mm(tsk, mm);

		if (tsk->vfork_done)
		complete_vfork_done(tsk);

		/*
		* If we're exiting normally, clear a user-space tid field if
		* requested. We leave this alone when dying by signal, to leave
		@@ -810,6 +807,13 @@ void mm_release(struct task_struct tsk, struct mm_struct mm)
		}
		tsk->clear_child_tid = NULL;
		}

		/*
		* All done, finally we can wake up parent and return this mm to him.
		* Also kthread_stop() uses this completion for synchronization.
		*/
		if (tsk->vfork_done)
		complete_vfork_done(tsk);
		}

		/*