RE: [PATCH] arm64: dts: renesas: r8a7796: Add CMT device nodes

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Vincent,

Thanks for the update. I am still seeing the same deadlock.

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index fb5e2b6..a96641a 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -155,7 +155,7 @@ u64 pm_runtime_autosuspend_expiration(struct device *dev)

        expires  = READ_ONCE(dev->power.last_busy);
        expires += (u64)autosuspend_delay * NSEC_PER_MSEC;
-       if (expires > ktime_to_ns(ktime_get()))
+       if (expires > ktime_get_mono_fast_ns())
                return expires; /* Expires in the future */

        return 0;
@@ -921,7 +921,7 @@ static enum hrtimer_restart  pm_suspend_timer_fn(struct hrtimer *timer)
         * If 'expires' is after the current time, we've been called
         * too early.
         */
-       if (expires > 0 && expires < ktime_to_ns(ktime_get())) {
+       if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
                dev->power.timer_expires = 0;
                rpm_suspend(dev, dev->power.timer_autosuspends ?
                    (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
@@ -940,7 +940,7 @@ static enum hrtimer_restart  pm_suspend_timer_fn(struct hrtimer *timer)
 int pm_schedule_suspend(struct device *dev, unsigned int delay)
 {
        unsigned long flags;
-       ktime_t expires;
+       u64 expires;
        int retval;

        spin_lock_irqsave(&dev->power.lock, flags);
@@ -957,8 +957,8 @@ int pm_schedule_suspend(struct device *dev, unsigned int delay)
        /* Other scheduled or pending requests need to be canceled. */
        pm_runtime_cancel_pending(dev);

-       expires = ktime_add(ktime_get(), ms_to_ktime(delay));
-       dev->power.timer_expires = ktime_to_ns(expires);
+       expires = ktime_get_mono_fast_ns() + ((u64)delay * NSEC_PER_MSEC);
+       dev->power.timer_expires = expires;
        dev->power.timer_autosuspends = 0;
        hrtimer_start(&dev->power.suspend_timer, expires, HRTIMER_MODE_ABS);


please find the logs.

root@salvator-x:~# echo  e60f0000.timer > /sys/devices/system/clocksource/clocksource0/current_clocksource
[   42.769260]
[   42.770760] ============================================
[   42.776068] WARNING: possible recursive locking detected
[   42.781378] 5.0.0-rc3-next-20190125-00001-gfa6709c-dirty #33 Not tainted
[   42.788076] --------------------------------------------
[   42.793385] migration/0/11 is trying to acquire lock:
[   42.798435] 00000000b43b7183 (tk_core.seq){----}, at: rpm_resume+0x5f0/0x7a8
[   42.805497]
[   42.805497] but task is already holding lock:
[   42.811326] 00000000b43b7183 (tk_core.seq){----}, at: multi_cpu_stop+0x8c/0x140
[   42.818641]
[   42.818641] other info that might help us debug this:
[   42.825165]  Possible unsafe locking scenario:
[   42.825165]
[   42.831080]        CPU0
[   42.833521]        ----
[   42.835962]   lock(tk_core.seq);
[   42.839185]   lock(tk_core.seq);
[   42.842409]
[   42.842409]  *** DEADLOCK ***
[   42.842409]
[   42.848328]  May be due to missing lock nesting notation
[   42.848328]
[   42.855115] 4 locks held by migration/0/11:
[   42.859293]  #0: 00000000a7511731 (timekeeper_lock){-.-.}, at: change_clocksource+0x2c/0x118
[   42.867738]  #1: 00000000b43b7183 (tk_core.seq){----}, at: multi_cpu_stop+0x8c/0x140
[   42.875484]  #2: 00000000b54c38a2 (&ch->lock){....}, at: sh_cmt_start+0x28/0x200
[   42.882887]  #3: 0000000010d14eec (&(&dev->power.lock)->rlock){-...}, at: __rpm_callback+0xbc/0x1e8
[   42.891937]
[   42.891937] stack backtrace:
[   42.896294] CPU: 0 PID: 11 Comm: migration/0 Not tainted 5.0.0-rc3-next-20190125-00001-gfa6709c-dirty #33
[   42.905860] Hardware name: Renesas Salvator-X 2nd version board based on r8a7796 (DT)
[   42.913689] Call trace:
[   42.916137]  dump_backtrace+0x0/0x178
[   42.919796]  show_stack+0x14/0x20
[   42.923111]  dump_stack+0xb0/0xec
[   42.926425]  __lock_acquire+0xfb4/0x1c08
[   42.930345]  lock_acquire+0xd0/0x268
[   42.933917]  ktime_get+0x5c/0x108
[   42.937229]  rpm_resume+0x5f0/0x7a8
[   42.940714]  __pm_runtime_resume+0x50/0x98
[   42.944807]  sh_cmt_start+0x84/0x200
[   42.948380]  sh_cmt_clocksource_enable+0x28/0x48
[   42.952995]  change_clocksource+0x84/0x118
[   42.957087]  multi_cpu_stop+0x8c/0x140
[   42.960834]  cpu_stopper_thread+0xac/0x120
[   42.964931]  smpboot_thread_fn+0x1ac/0x2c8
[   42.969024]  kthread+0x12c/0x130
[   42.972249]  ret_from_fork+0x10/0x18

Regards,
Biju

> -----Original Message-----
> From: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
> Sent: 25 January 2019 14:06
> Subject: Re: [PATCH] arm64: dts: renesas: r8a7796: Add CMT device nodes
>
> Hi Biju,
>
> It seems that the call of mark_last_busy in rpm_resume raises this problem.
> We have the sequence:
> change_clocksource
>
>     write_seqcount_begin
>     ...
>     timekeeping_update
>         ...
>         sh_cmt_clocksource_enable
>             ...
>             rpm_resume
>                 pm_runtime_mark_last_busy
>                     ktime_get
>                         do
>                             read_seqcount_begin
>                         while read_seqcount_retry
>     ....
>     write_seqcount_end
>
> In fact, we should be safe because we haven't yet changed the clocksource
> as we are enabling the clocksource that will be used for the switch.
>
> Can you try the patch below ?
> It uses ktime_get_mono_fast_ns instead which is lock safe for such case
>
> ---
>  drivers/base/power/runtime.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
> index 457be03..708a13f 100644
> --- a/drivers/base/power/runtime.c
> +++ b/drivers/base/power/runtime.c
> @@ -130,7 +130,7 @@ u64 pm_runtime_autosuspend_expiration(struct
> device *dev)  {
>  int autosuspend_delay;
>  u64 last_busy, expires = 0;
> -u64 now = ktime_to_ns(ktime_get());
> +u64 now = ktime_get_mono_fast_ns();
>
>  if (!dev->power.use_autosuspend)
>  goto out;
> @@ -909,7 +909,7 @@ static enum hrtimer_restart
> pm_suspend_timer_fn(struct hrtimer *timer)
>   * If 'expires' is after the current time, we've been called
>   * too early.
>   */
> -if (expires > 0 && expires < ktime_to_ns(ktime_get())) {
> +if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
>  dev->power.timer_expires = 0;
>  rpm_suspend(dev, dev->power.timer_autosuspends ?
>      (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC); @@ -928,7
> +928,7 @@ static enum hrtimer_restart  pm_suspend_timer_fn(struct
> hrtimer *timer)  int pm_schedule_suspend(struct device *dev, unsigned int
> delay)  {
>  unsigned long flags;
> -ktime_t expires;
> +u64 expires;
>  int retval;
>
>  spin_lock_irqsave(&dev->power.lock, flags); @@ -945,8 +945,8 @@
> int pm_schedule_suspend(struct device *dev, unsigned int delay)
>  /* Other scheduled or pending requests need to be canceled. */
>  pm_runtime_cancel_pending(dev);
>
> -expires = ktime_add(ktime_get(), ms_to_ktime(delay));
> -dev->power.timer_expires = ktime_to_ns(expires);
> +expires = ktime_get_mono_fast_ns() + (u64)delay *
> NSEC_PER_MSEC);
> +dev->power.timer_expires = expires;
>  dev->power.timer_autosuspends = 0;
>  hrtimer_start(&dev->power.suspend_timer, expires,
> HRTIMER_MODE_ABS);
>
> --
> 2.7.4
>
> Le Friday 25 Jan 2019 à 12:26:54 (+0000), Biju Das a écrit :
> > Hi All,
> >
> > I have enabled lock debugging  and it is showing "possible recursive locking
> detected "with the patch ("8234f6734c5d74ac794e5517437f51c57d65f865"
> PM-runtime: Switch autosuspend over to using hrtimers)
> >
> > root@salvator-x:~# echo  e60f0000.timer >
> /sys/devices/system/clocksource/clocksource0/current_clocksource
> > [   67.995854]
> > [   67.997354] ============================================
> > [   68.002663] WARNING: possible recursive locking detected
> > [   68.007974] 5.0.0-rc3-next-20190125-00005-g382822b #31 Not tainted
> > [   68.014150] --------------------------------------------
> > [   68.019459] migration/0/11 is trying to acquire lock:
> > [   68.024509] 0000000065de5fdf (tk_core.seq){----}, at:
> rpm_resume+0x5f0/0x7a8
> > [   68.031570]
> > [   68.031570] but task is already holding lock:
> > [   68.037399] 0000000065de5fdf (tk_core.seq){----}, at:
> multi_cpu_stop+0x8c/0x140
> > [   68.044714]
> > [   68.044714] other info that might help us debug this:
> > [   68.051237]  Possible unsafe locking scenario:
> > [   68.051237]
> > [   68.057153]        CPU0
> > [   68.059594]        ----
> > [   68.062034]   lock(tk_core.seq);
> > [   68.065258]   lock(tk_core.seq);
> > [   68.068482]
> > [   68.068482]  *** DEADLOCK ***
> > [   68.068482]
> > [   68.074402]  May be due to missing lock nesting notation
> > [   68.074402]
> > [   68.081188] 4 locks held by migration/0/11:
> > [   68.085366]  #0: 00000000463b6446 (timekeeper_lock){-.-.}, at:
> change_clocksource+0x2c/0x118
> > [   68.093812]  #1: 0000000065de5fdf (tk_core.seq){----}, at:
> multi_cpu_stop+0x8c/0x140
> > [   68.101558]  #2: 0000000098b45550 (&ch->lock){....}, at:
> sh_cmt_start+0x28/0x200
> > [   68.108961]  #3: 00000000da0f4e80 (&(&dev->power.lock)->rlock){-...}, at:
> __rpm_callback+0xbc/0x1e8
> > [   68.118011]
> > [   68.118011] stack backtrace:
> > [   68.122368] CPU: 0 PID: 11 Comm: migration/0 Not tainted 5.0.0-rc3-next-
> 20190125-00005-g382822b #31
> > [   68.131412] Hardware name: Renesas Salvator-X 2nd version board based
> on r8a7796 (DT)
> > [   68.139240] Call trace:
> > [   68.141687]  dump_backtrace+0x0/0x178
> > [   68.145346]  show_stack+0x14/0x20
> > [   68.148661]  dump_stack+0xb0/0xec
> > [   68.151975]  __lock_acquire+0xfb4/0x1c08
> > [   68.155894]  lock_acquire+0xd0/0x268
> > [   68.159467]  ktime_get+0x5c/0x108
> > [   68.162779]  rpm_resume+0x5f0/0x7a8
> > [   68.166265]  __pm_runtime_resume+0x50/0x98
> > [   68.170358]  sh_cmt_start+0x84/0x200
> > [   68.173931]  sh_cmt_clocksource_enable+0x28/0x48
> > [   68.178546]  change_clocksource+0x84/0x118
> > [   68.182639]  multi_cpu_stop+0x8c/0x140
> > [   68.186385]  cpu_stopper_thread+0xac/0x120
> > [   68.190481]  smpboot_thread_fn+0x1ac/0x2c8
> > [   68.194574]  kthread+0x12c/0x130
> > [   68.197800]  ret_from_fork+0x10/0x18
> >
> > Regards,
> > Biju
> >
> > > -----Original Message-----
> > > From: Biju Das
> > > Sent: 25 January 2019 11:27
> > > To: 'Geert Uytterhoeven' <geert@xxxxxxxxxxxxxx>; Vincent Guittot
> > > <vincent.guittot@xxxxxxxxxx>; Sergei Shtylyov
> > > <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
> > > Cc: Rob Herring <robh+dt@xxxxxxxxxx>; Mark Rutland
> > > <mark.rutland@xxxxxxx>; Simon Horman <horms@xxxxxxxxxxxx>;
> Magnus
> > > Damm <magnus.damm@xxxxxxxxx>; Linux-Renesas <linux-renesas-
> > > soc@xxxxxxxxxxxxxxx>; open list:OPEN FIRMWARE AND FLATTENED
> DEVICE
> > > TREE BINDINGS <devicetree@xxxxxxxxxxxxxxx>; Geert Uytterhoeven
> > > <geert+renesas@xxxxxxxxx>; Chris Paterson
> > > <Chris.Paterson2@xxxxxxxxxxx>; Daniel Lezcano
> > > <daniel.lezcano@xxxxxxxxxx>; Thomas Gleixner <tglx@xxxxxxxxxxxxx>;
> > > John Stultz <john.stultz@xxxxxxxxxx>; Fabrizio Castro
> > > <fabrizio.castro@xxxxxxxxxxxxxx>; Samuel Holland
> > > <samuel@xxxxxxxxxxxx>
> > > Subject: RE: [PATCH] arm64: dts: renesas: r8a7796: Add CMT device
> > > nodes
> > >
> > > Hi Geert,
> > >
> > > Thanks for the feedback. I started testing CMT on latest
> > > kernel(Linux-next-
> > > 20190125 and also renesas-dev) and found that it is broken on R-Car
> > > M3-W device.
> > >
> > > On further investigation the patch ("
> > > 8234f6734c5d74ac794e5517437f51c57d65f865"   PM-runtime: Switch
> > > autosuspend over to using hrtimers)  is causing the issue.
> > >
> > > During clock source switching, It calls the function "sh_cmt_enable"
> > > which calls " pm_runtime_get_sync(&ch->cmt->pdev->dev);"  and after
> > > that console freezes.
> > >
> > > Sergei: Have you noticed this issue  on R-Car V3M and V3H boards
> > > with latest kernel?
> > >
> > > Regards,
> > > Biju
> > >
> > > > -----Original Message-----
> > > > From: linux-renesas-soc-owner@xxxxxxxxxxxxxxx <linux-renesas-soc-
> > > > owner@xxxxxxxxxxxxxxx> On Behalf Of Geert Uytterhoeven
> > > > Sent: 24 January 2019 10:16
> > > > To: Biju Das <biju.das@xxxxxxxxxxxxxx>
> > > > Cc: Rob Herring <robh+dt@xxxxxxxxxx>; Mark Rutland
> > > > <mark.rutland@xxxxxxx>; Simon Horman <horms@xxxxxxxxxxxx>;
> > > Magnus Damm
> > > > <magnus.damm@xxxxxxxxx>; Linux-Renesas <linux-renesas-
> > > > soc@xxxxxxxxxxxxxxx>; open list:OPEN FIRMWARE AND FLATTENED
> DEVICE
> > > > TREE BINDINGS <devicetree@xxxxxxxxxxxxxxx>; Geert Uytterhoeven
> > > > <geert+renesas@xxxxxxxxx>; Chris Paterson
> > > > <Chris.Paterson2@xxxxxxxxxxx>; Daniel Lezcano
> > > > <daniel.lezcano@xxxxxxxxxx>; Thomas Gleixner <tglx@xxxxxxxxxxxxx>;
> > > > John Stultz <john.stultz@xxxxxxxxxx>; Fabrizio Castro
> > > > <fabrizio.castro@xxxxxxxxxxxxxx>; Samuel Holland
> > > <samuel@xxxxxxxxxxxx>
> > > > Subject: Re: [PATCH] arm64: dts: renesas: r8a7796: Add CMT device
> > > > nodes
> > > >
> > > > Hi Biju,
> > > >
> > > > On Fri, Oct 26, 2018 at 10:32 AM Biju Das
> > > > <biju.das@xxxxxxxxxxxxxx>
> > > wrote:
> > > > > This patch adds CMT{0|1|2|3} device nodes for r8a7796 SoC.
> > > > >
> > > > > Signed-off-by: Biju Das <biju.das@xxxxxxxxxxxxxx>
> > > > > ---
> > > > > This patch is tested against renesas-dev
> > > > >
> > > > > I have executed on inconsistency-check, nanosleep and
> > > > > clocksource_switch selftests on this arm64 SoC. The
> > > > > inconsistency-check and nanosleep tests are working fine.The
> > > > > clocksource_switch asynchronous test is failing due to
> > > > > inconsistency-check
> > > > failure on "arch_sys_counter".
> > > > >
> > > > > But if i skip the clocksource_switching of "arch_sys_counter",
> > > > > the asynchronous test is passing for CMT0/1/2/3 timer.
> > > > >
> > > > > Has any one noticed this issue?
> > > >
> > > > clockevents/next now has commit 7cd6dca3600d8d71
> > > > ("clocksource/drivers/arch_timer: Workaround for Allwinner A64
> > > > timer instability").  Perhaps this is related, and the same test
> > > > program may indicate similar issues?
> > > >
> > > > See also https://lore.kernel.org/lkml/20190113021719.46457-2-
> > > > samuel@xxxxxxxxxxxx/
> > > >
> > > > Gr{oetje,eeting}s,
> > > >
> > > >                         Geert
> > > >
> > > > --
> > > > Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
> > > > geert@linux- m68k.org
> > > >
> > > > In personal conversations with technical people, I call myself a
> > > > hacker. But when I'm talking to journalists I just say
> > > > "programmer" or
> > > something like that.
> > > >                                 -- Linus Torvalds
> >
> >
> >
> > Renesas Electronics Europe Ltd, Dukes Meadow, Millboard Road, Bourne
> End, Buckinghamshire, SL8 5FH, UK. Registered in England & Wales under
> Registered No. 04586709.



Renesas Electronics Europe Ltd, Dukes Meadow, Millboard Road, Bourne End, Buckinghamshire, SL8 5FH, UK. Registered in England & Wales under Registered No. 04586709.




[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]


  Powered by Linux