From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755324AbcAOKqK (ORCPT ); Fri, 15 Jan 2016 05:46:10 -0500 Received: from terminus.zytor.com ([198.137.202.10]:58682 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751586AbcAOKqH (ORCPT ); Fri, 15 Jan 2016 05:46:07 -0500 Date: Fri, 15 Jan 2016 02:45:43 -0800 From: tip-bot for Alexandre Belloni Message-ID: Cc: alexandre.belloni@free-electrons.com, boris.brezillon@free-electrons.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, mingo@kernel.org, nicolas.ferre@atmel.com, hpa@zytor.com, daniel.lezcano@linaro.org Reply-To: tglx@linutronix.de, alexandre.belloni@free-electrons.com, boris.brezillon@free-electrons.com, linux-kernel@vger.kernel.org, hpa@zytor.com, nicolas.ferre@atmel.com, mingo@kernel.org, daniel.lezcano@linaro.org In-Reply-To: <1452854061-30370-1-git-send-email-alexandre.belloni@free-electrons.com> References: <1452854061-30370-1-git-send-email-alexandre.belloni@free-electrons.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:timers/urgent] clockevents/tcb_clksrc: Prevent disabling an already disabled clock Git-Commit-ID: f02b4b72d12cbae7020a959e2ed0410a464b4cc4 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: f02b4b72d12cbae7020a959e2ed0410a464b4cc4 Gitweb: http://git.kernel.org/tip/f02b4b72d12cbae7020a959e2ed0410a464b4cc4 Author: Alexandre Belloni AuthorDate: Fri, 15 Jan 2016 11:34:21 +0100 Committer: Thomas Gleixner CommitDate: Fri, 15 Jan 2016 11:40:44 +0100 clockevents/tcb_clksrc: Prevent disabling an already disabled clock clockevents_exchange_device is calling clockevents_shutdown() on the new clockenvents device but it may have never been enabled in the first place. This results in the tcb clock being disabled without being enabled first: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1 at drivers/clk/clk.c:680 clk_disable+0x28/0x34() Modules linked in: CPU: 0 PID: 1 Comm: swapper Not tainted 4.4.0+ #6 Hardware name: Atmel AT91SAM9 [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (warn_slowpath_common+0x78/0xa0) [] (warn_slowpath_common) from [] (warn_slowpath_null+0x18/0x20) [] (warn_slowpath_null) from [] (clk_disable+0x28/0x34) [] (clk_disable) from [] (tc_shutdown+0x38/0x4c) [] (tc_shutdown) from [] (clockevents_switch_state+0x38/0x6c) [] (clockevents_switch_state) from [] (clockevents_shutdown+0x10/0x24) [] (clockevents_shutdown) from [] (tick_check_new_device+0x84/0xac) [] (tick_check_new_device) from [] (clockevents_register_device+0x7c/0x108) [] (clockevents_register_device) from [] (tcb_clksrc_init+0x390/0x3e8) [] (tcb_clksrc_init) from [] (do_one_initcall+0x114/0x1d4) [] (do_one_initcall) from [] (kernel_init_freeable+0xfc/0x1b8) [] (kernel_init_freeable) from [] (kernel_init+0x8/0xe0) [] (kernel_init) from [] (ret_from_fork+0x14/0x24) ---[ end trace 0000000000000001 ]--- Check what state we were in before trying to disable the clock. Fixes: cf4541c101ea ("clockevents/drivers/tcb_clksrc: Migrate to new 'set-state' interface") Signed-off-by: Alexandre Belloni Cc: Nicolas Ferre Cc: Boris Brezillon Cc: linux-arm-kernel@lists.infradead.org Cc: Daniel Lezcano Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1452854061-30370-1-git-send-email-alexandre.belloni@free-electrons.com Signed-off-by: Thomas Gleixner --- drivers/clocksource/tcb_clksrc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c index 6ee9140..4da2af9 100644 --- a/drivers/clocksource/tcb_clksrc.c +++ b/drivers/clocksource/tcb_clksrc.c @@ -98,7 +98,8 @@ static int tc_shutdown(struct clock_event_device *d) __raw_writel(0xff, regs + ATMEL_TC_REG(2, IDR)); __raw_writel(ATMEL_TC_CLKDIS, regs + ATMEL_TC_REG(2, CCR)); - clk_disable(tcd->clk); + if (!clockevent_state_detached(d)) + clk_disable(tcd->clk); return 0; }