Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753983Ab0LFQ6d (ORCPT ); Mon, 6 Dec 2010 11:58:33 -0500 Received: from hera.kernel.org ([140.211.167.34]:59711 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753899Ab0LFQ61 (ORCPT ); Mon, 6 Dec 2010 11:58:27 -0500 From: Tejun Heo To: oleg@redhat.com, roland@redhat.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, rjw@sisk.pl, jan.kratochvil@redhat.com Cc: Tejun Heo Subject: [PATCH 01/16] signal: fix SIGCONT notification code Date: Mon, 6 Dec 2010 17:56:49 +0100 Message-Id: <1291654624-6230-2-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1291654624-6230-1-git-send-email-tj@kernel.org> References: <1291654624-6230-1-git-send-email-tj@kernel.org> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Mon, 06 Dec 2010 16:57:37 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1910 Lines: 52 After a task receives SIGCONT, its parent is notified via SIGCHLD with its siginfo describing what the notified event is. If SIGCONT is received while the child process is stopped, the code should be CLD_CONTINUED. If SIGCONT is recieved while the child process is in the process of being stopped, it should be CLD_STOPPED. Which code to use is determined in prepare_signal() and recorded in signal->flags using SIGNAL_CLD_CONTINUED|STOP flags. get_signal_deliver() should test these flags and then notify accoringly; however, it incorrectly tested SIGNAL_STOP_CONTINUED instead of SIGNAL_CLD_CONTINUED, thus incorrectly notifying CLD_CONTINUED if the signal is delivered before the task is wait(2)ed and CLD_STOPPED if the state was fetched already. Fix it by testing SIGNAL_CLD_CONTINUED. While at it, uncompress the ?: test into if/else clause for better readability. Signed-off-by: Tejun Heo Reviewed-by: Oleg Nesterov Acked-by: Roland McGrath --- kernel/signal.c | 9 +++++++-- 1 files changed, 7 insertions(+), 2 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index 4e3cff1..fe004b5 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1853,8 +1853,13 @@ relock: * the CLD_ si_code into SIGNAL_CLD_MASK bits. */ if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { - int why = (signal->flags & SIGNAL_STOP_CONTINUED) - ? CLD_CONTINUED : CLD_STOPPED; + int why; + + if (signal->flags & SIGNAL_CLD_CONTINUED) + why = CLD_CONTINUED; + else + why = CLD_STOPPED; + signal->flags &= ~SIGNAL_CLD_MASK; why = tracehook_notify_jctl(why, CLD_CONTINUED); -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/