linux-kernel - Re: [PATCH] clocksource: sh_mtu2: Fix multiple shutdown call issue

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Message-ID: <2895339.LQpKMOfDKq@avalon>
Date:	Fri, 30 Oct 2015 15:35 +0200
From:	Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:	Magnus Damm <magnus.damm@...il.com>
Cc:	daniel.lezcano@...aro.org,
	laurent.pinchart+renesas@...asonboard.com, geert+renesas@...der.be,
	linux-sh@...r.kernel.org, viresh.kumar@...aro.org,
	linux-kernel@...r.kernel.org, chris.brandt@...esas.com,
	horms+renesas@...ge.net.au, tglx@...utronix.de
Subject: Re: [PATCH] clocksource: sh_mtu2: Fix multiple shutdown call issue

Hi Magnus,

Thank you for the patch.

On Wednesday 28 October 2015 10:43:23 Magnus Damm wrote:
> From: Magnus Damm <damm+renesas@...nsource.se>
> 
> On the r7s72100 Genmai board the MTU2 driver currently triggers a common
> clock framework WARN_ON(enable_count) when disabling the clock due to
> the MTU2 driver after recent callback rework may call ->set_state_shutdown()
> multiple times. A similar issue was spotted for the TMU driver and fixed
> in: 452b132 clocksource/drivers/sh_tmu: Fix traceback spotted in -next
> 
> On r7s72100 Genmai v4.3-rc7 built with shmobile_defconfig spits out the
> following during boot:
> 
> sh_mtu2 fcff0000.timer: ch0: used for clock events
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 1 at drivers/clk/clk.c:675 clk_core_disable+0x2c/0x6c()
> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.3.0-rc7 #1
> Hardware name: Generic R7S72100 (Flattened Device Tree)
> Backtrace:
> [<c00133d4>] (dump_backtrace) from [<c0013570>] (show_stack+0x18/0x1c)
>  r6:c0621fde r5:00000009 r4:00000000 r3:00200040
>  [<c0013558>] (show_stack) from [<c01c7aac>] (dump_stack+0x74/0x90)
>  [<c01c7a38>] (dump_stack) from [<c00272fc>]
> (warn_slowpath_common+0x88/0xb4) r4:00000000 r3:00000000
>   [<c0027274>] (warn_slowpath_common) from [<c0027400>]
> (warn_slowpath_null+0x24/0x2c) r8:c78c0400 r7:c7ee8df8 r6:00000000
> r5:600001d3 r4:c7806480
>    [<c00273dc>] (warn_slowpath_null) from [<c03a9320>]
> (clk_core_disable+0x2c/0x6c) [<c03a92f4>] (clk_core_disable) from
> [<c03aa0a0>] (clk_disable+0x40/0x4c) r4:c791be40 r3:00000000
>     [<c03aa060>] (clk_disable) from [<c0395d2c>] (sh_mtu2_disable+0x24/0x50)
> r5:00000001 r4:c7963c00
>      [<c0395d08>] (sh_mtu2_disable) from [<c0395d6c>]
> (sh_mtu2_clock_event_shutdown+0x14/0x1c) r4:c7963c40 r3:c0395d58
>       [<c0395d58>] (sh_mtu2_clock_event_shutdown) from [<c007d7d0>]
> (clockevents_switch_state+0xc8/0x114) [<c007d708>]
> (clockevents_switch_state) from [<c007d834>]
> (clockevents_shutdown+0x18/0x28) r5:c7963c40 r4:c7963c40
>        [<c007d81c>] (clockevents_shutdown) from [<c007dd58>]
> (clockevents_exchange_device+0x70/0x78) r4:00000000 r3:00000000
> 	[<c007dce8>] (clockevents_exchange_device) from [<c007e578>]
> (tick_check_new_device+0x88/0xe0) r5:00000000 r4:c7963c40
> 	 [<c007e4f0>] (tick_check_new_device) from [<c007daf0>]
> (clockevents_register_device+0xac/0x120) r7:00000000 r6:a0000153
> r5:c06ffe98 r4:c7963c40
> 	  [<c007da44>] (clockevents_register_device) from [<c0395be8>]
> (sh_mtu2_probe+0x230/0x350) r6:00000000 r5:c7963c00 r4:c791b040 r3:c06ff134
> 	   [<c03959b8>] (sh_mtu2_probe) from [<c028b6f0>]
> (platform_drv_probe+0x50/0x98)
> 
> Reported-by: Chris Brandt <chris.brandt@...esas.com>
> Fixes: 19a9ffb ("clockevents/drivers/sh_mtu2: Migrate to new 'set-state'
> interface") Cc: Viresh Kumar <viresh.kumar@...aro.org>
> Cc: Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>
> Signed-off-by: Magnus Damm <damm+renesas@...nsource.se>

Acked-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>

> ---
> 
>  drivers/clocksource/sh_mtu2.c |    4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> --- 0001/drivers/clocksource/sh_mtu2.c
> +++ work/drivers/clocksource/sh_mtu2.c	2015-10-27 16:20:07.350513000 +0900
> @@ -280,7 +280,9 @@ static int sh_mtu2_clock_event_shutdown(
>  {
>  	struct sh_mtu2_channel *ch = ced_to_sh_mtu2(ced);
> 
> -	sh_mtu2_disable(ch);
> +	if (clockevent_state_periodic(ced))
> +		sh_mtu2_disable(ch);
> +
>  	return 0;
>  }

-- 
Regards,

Laurent Pinchart

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