From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail333.us4.mandrillapp.com ([205.201.137.77]:36648 "EHLO mail333.us4.mandrillapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752825AbcCATJq (ORCPT ); Tue, 1 Mar 2016 14:09:46 -0500 Received: from pmta03.dal05.mailchimp.com (127.0.0.1) by mail333.us4.mandrillapp.com id hqnkfk174nou for ; Tue, 1 Mar 2016 19:09:42 +0000 (envelope-from ) From: Subject: Patch "clockevents/tcb_clksrc: Prevent disabling an already disabled clock" has been added to the 4.4-stable tree To: Cc: , Message-Id: <1456859381154217@kroah.com> Date: Tue, 01 Mar 2016 19:09:42 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled clockevents/tcb_clksrc: Prevent disabling an already disabled clock to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: clockevents-tcb_clksrc-prevent-disabling-an-already-disabled-clock.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From f02b4b72d12cbae7020a959e2ed0410a464b4cc4 Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Fri, 15 Jan 2016 11:34:21 +0100 Subject: clockevents/tcb_clksrc: Prevent disabling an already disabled clock From: Alexandre Belloni commit f02b4b72d12cbae7020a959e2ed0410a464b4cc4 upstream. 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 Link: http://lkml.kernel.org/r/1452854061-30370-1-git-send-email-alexandre.belloni@free-electrons.com Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- drivers/clocksource/tcb_clksrc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/clocksource/tcb_clksrc.c +++ b/drivers/clocksource/tcb_clksrc.c @@ -98,7 +98,8 @@ static int tc_shutdown(struct clock_even __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; } Patches currently in stable-queue which might be from alexandre.belloni@free-electrons.com are queue-4.4/clockevents-tcb_clksrc-prevent-disabling-an-already-disabled-clock.patch