Messages in this thread Patch in this message | | | Subject | [PATCH 2/2] mm: call complete_vfork_done() after clearing child_tid and flushing rss-counters | From | Konstantin Khlebnikov <> | Date | Thu, 12 Apr 2012 12:09:53 +0400 |
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Child should wake ups parent from vfork() only after finishing all operations with shared mm. There is no sense to use 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> --- kernel/fork.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/kernel/fork.c b/kernel/fork.c index 326bb5b..f10ac1d 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -728,9 +728,6 @@ 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 @@ -759,6 +756,13 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm) */ if (mm) sync_mm_rss(mm); + + /* + * 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); } /*
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