From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752027Ab0LVL3S (ORCPT ); Wed, 22 Dec 2010 06:29:18 -0500 Received: from mail-bw0-f67.google.com ([209.85.214.67]:61671 "EHLO mail-bw0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751253Ab0LVL3R (ORCPT ); Wed, 22 Dec 2010 06:29:17 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:from:to:cc:subject:date:message-id:x-mailer:in-reply-to :references; b=Z9L1KcFb3uLMWsvTXID0bPSTAMh8KgOCiGgRw/DC+OR4H2YrqK6fJ4KJrYMXMTV9Y8 aFRolsXG4G23cu7dqlimmspA62MaVdVslDg9l3AkH9fjxBwHtt0BWGBBzSlngZdi2Bbf ya/scEIVbJhmoINfyF26xOoUzJZ9tbrfmlcuo= From: Tejun Heo To: oleg@redhat.com, roland@redhat.com, linux-kernel@vger.kernel.org, rjw@sisk.pl, jan.kratochvil@redhat.com Cc: Tejun Heo Subject: [PATCH 2/4] ptrace: remove the extra wake_up_process() from ptrace_detach() Date: Wed, 22 Dec 2010 12:13:16 +0100 Message-Id: <1293016398-18001-3-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1293016398-18001-1-git-send-email-tj@kernel.org> References: <1293016398-18001-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This wake_up_process() has a turbulent history. This is a remnant from ancient ptrace implementation and patently wrong. Commit 95a3540d (ptrace_detach: the wrong wakeup breaks the ERESTARTxxx logic) removed it but the change was reverted later by commit edaba2c5 (ptrace: revert "ptrace_detach: the wrong wakeup breaks the ERESTARTxxx logic ") citing compatibility breakage and general brokeness of the whole group stop / ptrace interaction. Digging through the mailing archives, the compatibility breakage doesn't seem to be critical in the sense that the behavior isn't well defined or reliable to begin with and it seems to have been agreed to remove the wakeup with proper cleanup of the whole thing. Now that the group stop and its interaction with ptrace are cleaned up and well defined, it's high time to finally kill this silliness. Signed-off-by: Tejun Heo Acked-by: Oleg Nesterov Cc: Roland McGrath --- kernel/ptrace.c | 2 -- 1 files changed, 0 insertions(+), 2 deletions(-) diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 99bbaa3..a8c9f26 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -312,8 +312,6 @@ int ptrace_detach(struct task_struct *child, unsigned int data) if (child->ptrace) { child->exit_code = data; dead = __ptrace_detach(current, child); - if (!child->exit_state) - wake_up_process(child); } write_unlock_irq(&tasklist_lock); -- 1.7.1