From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935131Ab3BNXic (ORCPT ); Thu, 14 Feb 2013 18:38:32 -0500 Received: from mail-qc0-f202.google.com ([209.85.216.202]:48526 "EHLO mail-qc0-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759670Ab3BNXia (ORCPT ); Thu, 14 Feb 2013 18:38:30 -0500 From: Mandeep Singh Baines To: linux-kernel@vger.kernel.org Cc: Mandeep Singh Baines , Oleg Nesterov , Tejun Heo , Andrew Morton , "Rafael J. Wysocki" , Ingo Molnar Subject: [PATCH 1/5] vfork: don't freezer_count() for in-kernel users of CLONE_VFORK Date: Thu, 14 Feb 2013 15:38:12 -0800 Message-Id: <1360885096-21207-1-git-send-email-msb@chromium.org> X-Mailer: git-send-email 1.8.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We don't need to call freezer_do_not_count() for in-kernel users of CLONE_VFORK since exec will get called in bounded time. We don't want to call freezer_count() for in-kernel users because they may be holding locks. freezer_count() calls try_to_freeze(). We don't want to freeze an in-kernel user because it may be holding locks. In a follow-up patch, I call debug_check_no_locks_held() from try_to_freeze(). After applying this patch, I get no lockdep warnings with that patch. Signed-off-by: Mandeep Singh Baines CC: Oleg Nesterov CC: Tejun Heo CC: Andrew Morton CC: Rafael J. Wysocki CC: Ingo Molnar --- kernel/fork.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/fork.c b/kernel/fork.c index c535f33..a7cd973 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -722,9 +722,11 @@ static int wait_for_vfork_done(struct task_struct *child, { int killed; - freezer_do_not_count(); + if (current->mm) + freezer_do_not_count(); killed = wait_for_completion_killable(vfork); - freezer_count(); + if (current->mm) + freezer_count(); if (killed) { task_lock(child); -- 1.8.1