From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755231Ab1A1PJX (ORCPT ); Fri, 28 Jan 2011 10:09:23 -0500 Received: from mail-fx0-f46.google.com ([209.85.161.46]:51211 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754805Ab1A1PJP (ORCPT ); Fri, 28 Jan 2011 10:09:15 -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=sMVTpg1E7cYW8qGHOSkQEYLNvllZ4F85l16dZ0AIMmtzpgyK3W3EcrsuTK9Y7E10UQ l5hDOFiaaTLVP4+21TfMSuA4rHRFUSEyRM2EGjK0HJikhlGoz8ijDBXibGTKUkXupD6c n7BJUUXalTVZDo/aL5+ygaPHaQshjFrJ8JNXs= From: Tejun Heo To: roland@redhat.com, oleg@redhat.com, jan.kratochvil@redhat.com, linux-kernel@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, Tejun Heo Subject: [PATCH 08/10] ptrace: participate in group stop from ptrace_stop() iff the task is trapping for group stop Date: Fri, 28 Jan 2011 16:08:42 +0100 Message-Id: <1296227324-25295-9-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1296227324-25295-1-git-send-email-tj@kernel.org> References: <1296227324-25295-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, ptrace_stop() unconditionally participates in group stop bookkeeping. This is unnecessary and inaccurate. Make it only participate if the task is trapping for group stop - ie. if @why is CLD_STOPPED. As ptrace_stop() currently is not used when trapping for group stop, this equals to disabling group stop participation from ptrace_stop(). A visible behavior change is increased likelihood of delayed group stop completion if the thread group contains one or more ptraced tasks. This is to preapre for further cleanup of the interaction between group stop and ptrace. Signed-off-by: Tejun Heo Cc: Oleg Nesterov Cc: Roland McGrath --- kernel/signal.c | 9 ++++++--- 1 files changed, 6 insertions(+), 3 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index 7527778..2e20dad 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1694,10 +1694,13 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info) } /* - * If there is a group stop in progress, - * we must participate in the bookkeeping. + * If @why is CLD_STOPPED, we're trapping to participate in a group + * stop. Do the bookkeeping. Note that if SIGCONT was delievered + * while siglock was released for the arch hook, PENDING could be + * clear now. We act as if SIGCONT is received after TASK_TRACED + * is entered - ignore it. */ - if (current->group_stop & GROUP_STOP_PENDING) + if (why == CLD_STOPPED && (current->group_stop & GROUP_STOP_PENDING)) task_participate_group_stop(current); current->last_siginfo = info; -- 1.7.1