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authorKonstantin Khlebnikov <khlebnikov@openvz.org>2012-05-31 16:26:21 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-31 17:49:29 -0700
commitf7505d64f2db5da2d7d94873ddf2cd2524847061 (patch)
treea10aee9604306826816e8e5fc689201f49d7a6d0
parentbca15543736f9be6d84e0bbc262ea7069076b9e6 (diff)
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>
-rw-r--r--kernel/fork.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 017fb23d598..2254fbf2356 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -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);
}
/*