Re: [PATCH net] net: phy: Warn about incorrect mdio_bus_phy_resume() state

Re: [PATCH net] net: phy: Warn about incorrect mdio_bus_phy_resume() state

[Geert Uytterhoeven]

Hi Florian,

On Fri, Aug 12, 2022 at 6:39 PM Florian Fainelli <f.fainelli@gmail.com> wrote:
> On 8/12/22 04:19, Marek Szyprowski wrote:
> > On 02.08.2022 01:34, Florian Fainelli wrote:
> >> Calling mdio_bus_phy_resume() with neither the PHY state machine set to
> >> PHY_HALTED nor phydev->mac_managed_pm set to true is a good indication
> >> that we can produce a race condition looking like this:
> >>
> >> CPU0                                         CPU1
> >> bcmgenet_resume
> >>    -> phy_resume
> >>      -> phy_init_hw
> >>    -> phy_start
> >>      -> phy_resume
> >>                                                   phy_start_aneg()
> >> mdio_bus_phy_resume
> >>    -> phy_resume
> >>       -> phy_write(..., BMCR_RESET)
> >>        -> usleep()                                  -> phy_read()
> >>
> >> with the phy_resume() function triggering a PHY behavior that might have
> >> to be worked around with (see bf8bfc4336f7 ("net: phy: broadcom: Fix
> >> brcm_fet_config_init()") for instance) that ultimately leads to an error
> >> reading from the PHY.
> >>
> >> Fixes: fba863b81604 ("net: phy: make PHY PM ops a no-op if MAC driver manages PHY PM")
> >> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> >
> > This patch, as probably intended, triggers a warning during system
> > suspend/resume cycle in the SMSC911x driver. I've observed it on ARM
> > Juno R1 board on the kernel compiled from next-202208010:
> >
> >    ------------[ cut here ]------------
> >    WARNING: CPU: 1 PID: 398 at drivers/net/phy/phy_device.c:323
> > mdio_bus_phy_resume+0x34/0xc8

I am seeing the same on the ape6evm and kzm9g development
boards with smsc911x Ethernet, and on various boards with Renesas
Ethernet (sh_eth or ravb) if Wake-on-LAN is disabled.

> Yes this is catching an actual issue in the driver in that the PHY state
> machine is still running while the system is trying to suspend. We could
> go about fixing it in a different number of ways, though I believe this
> one is probably correct enough to work and fix the warning:

> --- a/drivers/net/ethernet/smsc/smsc911x.c
> +++ b/drivers/net/ethernet/smsc/smsc911x.c
> @@ -1037,6 +1037,8 @@ static int smsc911x_mii_probe(struct net_device *dev)
>                  return ret;
>          }
>
> +       /* Indicate that the MAC is responsible for managing PHY PM */
> +       phydev->mac_managed_pm = true;
>          phy_attached_info(phydev);
>
>          phy_set_max_speed(phydev, SPEED_100);
> @@ -2587,6 +2589,8 @@ static int smsc911x_suspend(struct device *dev)
>          if (netif_running(ndev)) {
>                  netif_stop_queue(ndev);
>                  netif_device_detach(ndev);
> +               if (!device_may_wakeup(dev))
> +                       phy_suspend(dev->phydev);
>          }
>
>          /* enable wake on LAN, energy detection and the external PME
> @@ -2628,6 +2632,8 @@ static int smsc911x_resume(struct device *dev)
>          if (netif_running(ndev)) {
>                  netif_device_attach(ndev);
>                  netif_start_queue(ndev);
> +               if (!device_may_wakeup(dev))
> +                       phy_resume(dev->phydev);
>          }
>
>          return 0;

Thanks for your patch, but unfortunately this does not work on ape6evm
and kzm9g, where the smsc911x device is connected to a power-managed
bus.  It looks like the PHY registers are accessed while the device
is already suspended, causing a crash during system suspend:

8<--- cut here ---
Unhandled fault: imprecise external abort (0x1406) at 0x00000000
[00000000] *pgd=00000000
Internal error: : 1406 [#1] SMP ARM
CPU: 2 PID: 75 Comm: kworker/2:2 Not tainted
6.0.0-rc1-ape6evm-00977-gdc70725fbca5-dirty #375
Hardware name: Generic R8A73A4 (Flattened Device Tree)
Workqueue: events_power_efficient phy_state_machine
PC is at smsc911x_reg_read+0x30/0x48
LR is at smsc911x_reg_read+0x30/0x48
pc : [<c03807cc>]    lr : [<c03807cc>]    psr: 20030093
sp : f0891e30  ip : 00000000  fp : eff98605
r10: c092af80  r9 : c202e6e8  r8 : 20030013
r7 : c202e70c  r6 : 000000a4  r5 : 20030093  r4 : c202e6c0
r3 : f0a31000  r2 : 00000002  r1 : f0a310a4  r0 : 00000000
Flags: nzCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 10c5387d  Table: 4552006a  DAC: 00000051
Register r0 information: NULL pointer
Register r1 information: 0-page vmalloc region starting at 0xf0a31000
allocated at smsc911x_drv_probe+0x108/0x934
Register r2 information: non-paged memory
Register r3 information: 0-page vmalloc region starting at 0xf0a31000
allocated at smsc911x_drv_probe+0x108/0x934
Register r4 information: slab kmalloc-4k start c202e000 pointer offset
1728 size 4096
Register r5 information: non-paged memory
Register r6 information: non-paged memory
Register r7 information: slab kmalloc-4k start c202e000 pointer offset
1804 size 4096
Register r8 information: non-paged memory
Register r9 information: slab kmalloc-4k start c202e000 pointer offset
1768 size 4096
Register r10 information: non-slab/vmalloc memory
Register r11 information: non-slab/vmalloc memory
Register r12 information: NULL pointer
Process kworker/2:2 (pid: 75, stack limit = 0x5239c21f)
Stack: (0xf0891e30 to 0xf0892000)
1e20:                                     c202e6c0 00000006 c19da000 c202e6c0
1e40: 20030013 c03815bc 00000000 00000001 c19da000 c0381820 00000001 c19da000
1e60: c19da000 00000000 c39eacc0 00000000 c092af80 c037e694 c19da000 00000001
1e80: 00000000 c19da758 c19da000 00000001 00000000 c037e888 c29a0000 c29a03f4
1ea0: 00000078 c29a0448 c39eacc0 c037c878 c29a0000 c037cab4 c29a0000 c29a03f4
1ec0: c29a0000 c037fbc8 c29a0000 c29a03f4 c29a0000 c29a0448 00000004 c0377540
1ee0: c3ac8f00 c29a03f4 c29a0000 c0378588 009a03f4 c07cce88 c3ac8f00 c29a03f4
1f00: eff96780 00000000 eff98600 00000080 c092af80 c00426f0 00000001 00000000
1f20: c00425c4 c07cce88 c07bb574 00000000 c13fa5b8 c0da3f6c 00000000 c071c1da
1f40: 00000000 c07cce88 00000000 c3ac8f00 c3ac8f18 eff96780 c092a665 c07c9d00
1f60: eff967bc c0934e20 00000000 c0042b30 c2b8a500 c2ba65c0 c3ac8880 f0901ebc
1f80: c00428f0 c3ac8f00 00000000 c00494c4 c2ba65c0 c00493f4 00000000 00000000
1fa0: 00000000 00000000 00000000 c0009108 00000000 00000000 00000000 00000000
1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
1fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
 smsc911x_reg_read from smsc911x_mac_read+0x4c/0xa0
 smsc911x_mac_read from smsc911x_mii_read+0x38/0xb4
 smsc911x_mii_read from __mdiobus_read+0x70/0xc4
 __mdiobus_read from mdiobus_read+0x34/0x48
 mdiobus_read from genphy_update_link+0x10/0xc8
 genphy_update_link from genphy_read_status+0x10/0xc4
 genphy_read_status from lan87xx_read_status+0x10/0x11c
 lan87xx_read_status from phy_check_link_status+0x5c/0xbc
 phy_check_link_status from phy_state_machine+0x78/0x218
 phy_state_machine from process_one_work+0x2f0/0x4c4
 process_one_work from worker_thread+0x240/0x2d0
 worker_thread from kthread+0xd0/0xe0
 kthread from ret_from_fork+0x14/0x2c
Exception stack(0xf0891fb0 to 0xf0891ff8)
1fa0:                                     00000000 00000000 00000000 00000000
1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
1fe0: 00000000 00000000 00000000 00000000 00000013 00000000
Code: e5933000 e1a05000 e1a00004 e12fff33 (e1a01005)
---[ end trace 0000000000000000 ]---

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

Re: [PATCH net] net: phy: Warn about incorrect mdio_bus_phy_resume() state

[Florian Fainelli]

On 8/16/2022 6:20 AM, Geert Uytterhoeven wrote:
> Hi Florian,
> 
> On Fri, Aug 12, 2022 at 6:39 PM Florian Fainelli <f.fainelli@gmail.com> wrote:
>> On 8/12/22 04:19, Marek Szyprowski wrote:
>>> On 02.08.2022 01:34, Florian Fainelli wrote:
>>>> Calling mdio_bus_phy_resume() with neither the PHY state machine set to
>>>> PHY_HALTED nor phydev->mac_managed_pm set to true is a good indication
>>>> that we can produce a race condition looking like this:
>>>>
>>>> CPU0                                         CPU1
>>>> bcmgenet_resume
>>>>     -> phy_resume
>>>>       -> phy_init_hw
>>>>     -> phy_start
>>>>       -> phy_resume
>>>>                                                    phy_start_aneg()
>>>> mdio_bus_phy_resume
>>>>     -> phy_resume
>>>>        -> phy_write(..., BMCR_RESET)
>>>>         -> usleep()                                  -> phy_read()
>>>>
>>>> with the phy_resume() function triggering a PHY behavior that might have
>>>> to be worked around with (see bf8bfc4336f7 ("net: phy: broadcom: Fix
>>>> brcm_fet_config_init()") for instance) that ultimately leads to an error
>>>> reading from the PHY.
>>>>
>>>> Fixes: fba863b81604 ("net: phy: make PHY PM ops a no-op if MAC driver manages PHY PM")
>>>> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
>>>
>>> This patch, as probably intended, triggers a warning during system
>>> suspend/resume cycle in the SMSC911x driver. I've observed it on ARM
>>> Juno R1 board on the kernel compiled from next-202208010:
>>>
>>>     ------------[ cut here ]------------
>>>     WARNING: CPU: 1 PID: 398 at drivers/net/phy/phy_device.c:323
>>> mdio_bus_phy_resume+0x34/0xc8
> 
> I am seeing the same on the ape6evm and kzm9g development
> boards with smsc911x Ethernet, and on various boards with Renesas
> Ethernet (sh_eth or ravb) if Wake-on-LAN is disabled.
> 
>> Yes this is catching an actual issue in the driver in that the PHY state
>> machine is still running while the system is trying to suspend. We could
>> go about fixing it in a different number of ways, though I believe this
>> one is probably correct enough to work and fix the warning:
> 
>> --- a/drivers/net/ethernet/smsc/smsc911x.c
>> +++ b/drivers/net/ethernet/smsc/smsc911x.c
>> @@ -1037,6 +1037,8 @@ static int smsc911x_mii_probe(struct net_device *dev)
>>                   return ret;
>>           }
>>
>> +       /* Indicate that the MAC is responsible for managing PHY PM */
>> +       phydev->mac_managed_pm = true;
>>           phy_attached_info(phydev);
>>
>>           phy_set_max_speed(phydev, SPEED_100);
>> @@ -2587,6 +2589,8 @@ static int smsc911x_suspend(struct device *dev)
>>           if (netif_running(ndev)) {
>>                   netif_stop_queue(ndev);
>>                   netif_device_detach(ndev);
>> +               if (!device_may_wakeup(dev))
>> +                       phy_suspend(dev->phydev);
>>           }
>>
>>           /* enable wake on LAN, energy detection and the external PME
>> @@ -2628,6 +2632,8 @@ static int smsc911x_resume(struct device *dev)
>>           if (netif_running(ndev)) {
>>                   netif_device_attach(ndev);
>>                   netif_start_queue(ndev);
>> +               if (!device_may_wakeup(dev))
>> +                       phy_resume(dev->phydev);
>>           }
>>
>>           return 0;
> 
> Thanks for your patch, but unfortunately this does not work on ape6evm
> and kzm9g, where the smsc911x device is connected to a power-managed
> bus.  It looks like the PHY registers are accessed while the device
> is already suspended, causing a crash during system suspend:

Does it work better if you replace phy_suspend() with phy_stop() and 
phy_resume() with phy_start()?
-- 
Florian

Re: [PATCH net] net: phy: Warn about incorrect mdio_bus_phy_resume() state

[Geert Uytterhoeven]

Hi Florian,

On Wed, Aug 17, 2022 at 4:28 AM Florian Fainelli <f.fainelli@gmail.com> wrote:
> On 8/16/2022 6:20 AM, Geert Uytterhoeven wrote:
> > On Fri, Aug 12, 2022 at 6:39 PM Florian Fainelli <f.fainelli@gmail.com> wrote:
> >> On 8/12/22 04:19, Marek Szyprowski wrote:
> >>> On 02.08.2022 01:34, Florian Fainelli wrote:
> >>>> Calling mdio_bus_phy_resume() with neither the PHY state machine set to
> >>>> PHY_HALTED nor phydev->mac_managed_pm set to true is a good indication
> >>>> that we can produce a race condition looking like this:
> >>>>
> >>>> CPU0                                         CPU1
> >>>> bcmgenet_resume
> >>>>     -> phy_resume
> >>>>       -> phy_init_hw
> >>>>     -> phy_start
> >>>>       -> phy_resume
> >>>>                                                    phy_start_aneg()
> >>>> mdio_bus_phy_resume
> >>>>     -> phy_resume
> >>>>        -> phy_write(..., BMCR_RESET)
> >>>>         -> usleep()                                  -> phy_read()
> >>>>
> >>>> with the phy_resume() function triggering a PHY behavior that might have
> >>>> to be worked around with (see bf8bfc4336f7 ("net: phy: broadcom: Fix
> >>>> brcm_fet_config_init()") for instance) that ultimately leads to an error
> >>>> reading from the PHY.
> >>>>
> >>>> Fixes: fba863b81604 ("net: phy: make PHY PM ops a no-op if MAC driver manages PHY PM")
> >>>> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> >>>
> >>> This patch, as probably intended, triggers a warning during system
> >>> suspend/resume cycle in the SMSC911x driver. I've observed it on ARM
> >>> Juno R1 board on the kernel compiled from next-202208010:
> >>>
> >>>     ------------[ cut here ]------------
> >>>     WARNING: CPU: 1 PID: 398 at drivers/net/phy/phy_device.c:323
> >>> mdio_bus_phy_resume+0x34/0xc8
> >
> > I am seeing the same on the ape6evm and kzm9g development
> > boards with smsc911x Ethernet, and on various boards with Renesas
> > Ethernet (sh_eth or ravb) if Wake-on-LAN is disabled.
> >
> >> Yes this is catching an actual issue in the driver in that the PHY state
> >> machine is still running while the system is trying to suspend. We could
> >> go about fixing it in a different number of ways, though I believe this
> >> one is probably correct enough to work and fix the warning:
> >
> >> --- a/drivers/net/ethernet/smsc/smsc911x.c
> >> +++ b/drivers/net/ethernet/smsc/smsc911x.c
> >> @@ -1037,6 +1037,8 @@ static int smsc911x_mii_probe(struct net_device *dev)
> >>                   return ret;
> >>           }
> >>
> >> +       /* Indicate that the MAC is responsible for managing PHY PM */
> >> +       phydev->mac_managed_pm = true;
> >>           phy_attached_info(phydev);
> >>
> >>           phy_set_max_speed(phydev, SPEED_100);
> >> @@ -2587,6 +2589,8 @@ static int smsc911x_suspend(struct device *dev)
> >>           if (netif_running(ndev)) {
> >>                   netif_stop_queue(ndev);
> >>                   netif_device_detach(ndev);
> >> +               if (!device_may_wakeup(dev))
> >> +                       phy_suspend(dev->phydev);
> >>           }
> >>
> >>           /* enable wake on LAN, energy detection and the external PME
> >> @@ -2628,6 +2632,8 @@ static int smsc911x_resume(struct device *dev)
> >>           if (netif_running(ndev)) {
> >>                   netif_device_attach(ndev);
> >>                   netif_start_queue(ndev);
> >> +               if (!device_may_wakeup(dev))
> >> +                       phy_resume(dev->phydev);
> >>           }
> >>
> >>           return 0;
> >
> > Thanks for your patch, but unfortunately this does not work on ape6evm
> > and kzm9g, where the smsc911x device is connected to a power-managed
> > bus.  It looks like the PHY registers are accessed while the device
> > is already suspended, causing a crash during system suspend:
>
> Does it work better if you replace phy_suspend() with phy_stop() and
> phy_resume() with phy_start()?

Thank you, much better!
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

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

Re: [PATCH net] net: phy: Warn about incorrect mdio_bus_phy_resume() state

[Marek Szyprowski]

On 17.08.2022 11:18, Geert Uytterhoeven wrote:
> On Wed, Aug 17, 2022 at 4:28 AM Florian Fainelli <f.fainelli@gmail.com> wrote:
>> On 8/16/2022 6:20 AM, Geert Uytterhoeven wrote:
>>> On Fri, Aug 12, 2022 at 6:39 PM Florian Fainelli <f.fainelli@gmail.com> wrote:
>>>> On 8/12/22 04:19, Marek Szyprowski wrote:
>>>>> On 02.08.2022 01:34, Florian Fainelli wrote:
>>>>>> Calling mdio_bus_phy_resume() with neither the PHY state machine set to
>>>>>> PHY_HALTED nor phydev->mac_managed_pm set to true is a good indication
>>>>>> that we can produce a race condition looking like this:
>>>>>>
>>>>>> CPU0                                         CPU1
>>>>>> bcmgenet_resume
>>>>>>      -> phy_resume
>>>>>>        -> phy_init_hw
>>>>>>      -> phy_start
>>>>>>        -> phy_resume
>>>>>>                                                     phy_start_aneg()
>>>>>> mdio_bus_phy_resume
>>>>>>      -> phy_resume
>>>>>>         -> phy_write(..., BMCR_RESET)
>>>>>>          -> usleep()                                  -> phy_read()
>>>>>>
>>>>>> with the phy_resume() function triggering a PHY behavior that might have
>>>>>> to be worked around with (see bf8bfc4336f7 ("net: phy: broadcom: Fix
>>>>>> brcm_fet_config_init()") for instance) that ultimately leads to an error
>>>>>> reading from the PHY.
>>>>>>
>>>>>> Fixes: fba863b81604 ("net: phy: make PHY PM ops a no-op if MAC driver manages PHY PM")
>>>>>> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
>>>>> This patch, as probably intended, triggers a warning during system
>>>>> suspend/resume cycle in the SMSC911x driver. I've observed it on ARM
>>>>> Juno R1 board on the kernel compiled from next-202208010:
>>>>>
>>>>>      ------------[ cut here ]------------
>>>>>      WARNING: CPU: 1 PID: 398 at drivers/net/phy/phy_device.c:323
>>>>> mdio_bus_phy_resume+0x34/0xc8
>>> I am seeing the same on the ape6evm and kzm9g development
>>> boards with smsc911x Ethernet, and on various boards with Renesas
>>> Ethernet (sh_eth or ravb) if Wake-on-LAN is disabled.
>>>
>>>> Yes this is catching an actual issue in the driver in that the PHY state
>>>> machine is still running while the system is trying to suspend. We could
>>>> go about fixing it in a different number of ways, though I believe this
>>>> one is probably correct enough to work and fix the warning:
>>>> --- a/drivers/net/ethernet/smsc/smsc911x.c
>>>> +++ b/drivers/net/ethernet/smsc/smsc911x.c
>>>> @@ -1037,6 +1037,8 @@ static int smsc911x_mii_probe(struct net_device *dev)
>>>>                    return ret;
>>>>            }
>>>>
>>>> +       /* Indicate that the MAC is responsible for managing PHY PM */
>>>> +       phydev->mac_managed_pm = true;
>>>>            phy_attached_info(phydev);
>>>>
>>>>            phy_set_max_speed(phydev, SPEED_100);
>>>> @@ -2587,6 +2589,8 @@ static int smsc911x_suspend(struct device *dev)
>>>>            if (netif_running(ndev)) {
>>>>                    netif_stop_queue(ndev);
>>>>                    netif_device_detach(ndev);
>>>> +               if (!device_may_wakeup(dev))
>>>> +                       phy_suspend(dev->phydev);
>>>>            }
>>>>
>>>>            /* enable wake on LAN, energy detection and the external PME
>>>> @@ -2628,6 +2632,8 @@ static int smsc911x_resume(struct device *dev)
>>>>            if (netif_running(ndev)) {
>>>>                    netif_device_attach(ndev);
>>>>                    netif_start_queue(ndev);
>>>> +               if (!device_may_wakeup(dev))
>>>> +                       phy_resume(dev->phydev);
>>>>            }
>>>>
>>>>            return 0;
>>> Thanks for your patch, but unfortunately this does not work on ape6evm
>>> and kzm9g, where the smsc911x device is connected to a power-managed
>>> bus.  It looks like the PHY registers are accessed while the device
>>> is already suspended, causing a crash during system suspend:
>> Does it work better if you replace phy_suspend() with phy_stop() and
>> phy_resume() with phy_start()?
> Thank you, much better!
> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

It also works for me.

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH net] net: phy: Warn about incorrect mdio_bus_phy_resume() state

[Geert Uytterhoeven]

On Tue, Aug 16, 2022 at 3:20 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> On Fri, Aug 12, 2022 at 6:39 PM Florian Fainelli <f.fainelli@gmail.com> wrote:
> > On 8/12/22 04:19, Marek Szyprowski wrote:
> > > On 02.08.2022 01:34, Florian Fainelli wrote:
> > >> Calling mdio_bus_phy_resume() with neither the PHY state machine set to
> > >> PHY_HALTED nor phydev->mac_managed_pm set to true is a good indication
> > >> that we can produce a race condition looking like this:
> > >>
> > >> CPU0                                         CPU1
> > >> bcmgenet_resume
> > >>    -> phy_resume
> > >>      -> phy_init_hw
> > >>    -> phy_start
> > >>      -> phy_resume
> > >>                                                   phy_start_aneg()
> > >> mdio_bus_phy_resume
> > >>    -> phy_resume
> > >>       -> phy_write(..., BMCR_RESET)
> > >>        -> usleep()                                  -> phy_read()
> > >>
> > >> with the phy_resume() function triggering a PHY behavior that might have
> > >> to be worked around with (see bf8bfc4336f7 ("net: phy: broadcom: Fix
> > >> brcm_fet_config_init()") for instance) that ultimately leads to an error
> > >> reading from the PHY.
> > >>
> > >> Fixes: fba863b81604 ("net: phy: make PHY PM ops a no-op if MAC driver manages PHY PM")
> > >> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> > >
> > > This patch, as probably intended, triggers a warning during system
> > > suspend/resume cycle in the SMSC911x driver. I've observed it on ARM
> > > Juno R1 board on the kernel compiled from next-202208010:
> > >
> > >    ------------[ cut here ]------------
> > >    WARNING: CPU: 1 PID: 398 at drivers/net/phy/phy_device.c:323
> > > mdio_bus_phy_resume+0x34/0xc8
>
> I am seeing the same on the ape6evm and kzm9g development
> boards with smsc911x Ethernet, and on various boards with Renesas

So the smsc911x issue was fixed by commit 3ce9f2bef7552893
("net: smsc911x: Stop and start PHY during suspend and resume").

> Ethernet (sh_eth or ravb) if Wake-on-LAN is disabled.

The issue is still seen with sh_eth and ravb.  I have sent to fixes:
https://lore.kernel.org/r/c6e1331b9bef61225fa4c09db3ba3e2e7214ba2d.1663598886.git.geert+renesas@glider.be
https://lore.kernel.org/r/c6e1331b9bef61225fa4c09db3ba3e2e7214ba2d.1663598886.git.geert+renesas@glider.be

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