Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760605Ab3GZXo0 (ORCPT ); Fri, 26 Jul 2013 19:44:26 -0400 Received: from mail-wg0-f42.google.com ([74.125.82.42]:62500 "EHLO mail-wg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760214Ab3GZXn2 (ORCPT ); Fri, 26 Jul 2013 19:43:28 -0400 From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Steven Rostedt , "Paul E. McKenney" , Ingo Molnar , Thomas Gleixner , Peter Zijlstra , Borislav Petkov , Li Zhong , Mike Galbraith , Kevin Hilman Subject: [PATCH 18/21] vtime: Always debug check snapshot source _before_ updating it Date: Sat, 27 Jul 2013 01:42:41 +0200 Message-Id: <1374882164-32519-19-git-send-email-fweisbec@gmail.com> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <1374882164-32519-1-git-send-email-fweisbec@gmail.com> References: <1374882164-32519-1-git-send-email-fweisbec@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2012 Lines: 57 The vtime delta update performed by get_vtime_delta() always check that the source of the snapshot is valid. Meanhile the snapshot updaters that rely on get_vtime_delta() also set the new snapshot origin. But some of them do this right before the call to get_vtime_delta(), making its debug check useless. This is easily fixable by moving the snapshot origin update after the call to get_vtime_delta(). The order doesn't matter there. Signed-off-by: Frederic Weisbecker Cc: Steven Rostedt Cc: Paul E. McKenney Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Borislav Petkov Cc: Li Zhong Cc: Mike Galbraith Cc: Kevin Hilman --- kernel/sched/cputime.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index e9e742e..c1d7493 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -660,9 +660,9 @@ void vtime_account_system(struct task_struct *tsk) void vtime_gen_account_irq_exit(struct task_struct *tsk) { write_seqlock(&tsk->vtime_seqlock); + __vtime_account_system(tsk); if (context_tracking_in_user()) tsk->vtime_snap_whence = VTIME_USER; - __vtime_account_system(tsk); write_sequnlock(&tsk->vtime_seqlock); } @@ -680,8 +680,8 @@ void vtime_account_user(struct task_struct *tsk) void vtime_user_enter(struct task_struct *tsk) { write_seqlock(&tsk->vtime_seqlock); - tsk->vtime_snap_whence = VTIME_USER; __vtime_account_system(tsk); + tsk->vtime_snap_whence = VTIME_USER; write_sequnlock(&tsk->vtime_seqlock); } -- 1.7.5.4 -- 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/