2017-07-26 19:25:09

by Florian Fainelli

[permalink] [raw]
Subject: [PATCH net] net: phy: Run state machine to completion

Marc reported that he was not getting the PHY library adjust_link()
callback function to run when calling phy_stop() + phy_disconnect()
which does not indeed happen because we don't make sure we flush the
PHYLIB delayed work and let it run to completion. We also need to have
a synchronous call to phy_state_machine() in order to have the state
machine actually act on PHY_HALTED, set the PHY device's link down, turn
the network device's carrier off and finally call the adjust_link()
function.

Reported-by: Marc Gonzalez <[email protected]>
Fixes: a390d1f379cf ("phylib: convert state_queue work to delayed_work")
Signed-off-by: Florian Fainelli <[email protected]>
---
David, this dates back from before the commit mentioned in Fixes but it would
be hard to backport to earlier kernels if we flagged the original design flaw
that used timers. Also, I am not clear on the timer API whether there was a way
to ensure timers would run to completion before they would be cancelled.

Marc, please add your Signed-off-by tag since you contributed the second line.

Thanks!

drivers/net/phy/phy.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index d0626bf5c540..30e7c43e0d87 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -743,12 +743,17 @@ void phy_trigger_machine(struct phy_device *phydev, bool sync)
*/
void phy_stop_machine(struct phy_device *phydev)
{
+ /* Run the state machine to completion */
+ flush_delayed_work(&phydev->state_queue);
cancel_delayed_work_sync(&phydev->state_queue);

mutex_lock(&phydev->lock);
if (phydev->state > PHY_UP && phydev->state != PHY_HALTED)
phydev->state = PHY_UP;
mutex_unlock(&phydev->lock);
+
+ /* Now we can run the state machine synchronously */
+ phy_state_machine(&phydev->state_queue.work);
}

/**
--
2.9.3


2017-07-26 19:34:57

by Florian Fainelli

[permalink] [raw]
Subject: Re: [PATCH net] net: phy: Run state machine to completion

On 07/26/2017 12:24 PM, Florian Fainelli wrote:
> Marc reported that he was not getting the PHY library adjust_link()
> callback function to run when calling phy_stop() + phy_disconnect()
> which does not indeed happen because we don't make sure we flush the
> PHYLIB delayed work and let it run to completion. We also need to have
> a synchronous call to phy_state_machine() in order to have the state
> machine actually act on PHY_HALTED, set the PHY device's link down, turn
> the network device's carrier off and finally call the adjust_link()
> function.
>
> Reported-by: Marc Gonzalez <[email protected]>
> Fixes: a390d1f379cf ("phylib: convert state_queue work to delayed_work")
> Signed-off-by: Florian Fainelli <[email protected]>
> ---
> David, this dates back from before the commit mentioned in Fixes but it would
> be hard to backport to earlier kernels if we flagged the original design flaw
> that used timers. Also, I am not clear on the timer API whether there was a way
> to ensure timers would run to completion before they would be cancelled.
>
> Marc, please add your Signed-off-by tag since you contributed the second line.
>
> Thanks!

David, please hold off before applying this, I found a corner case with
power management where we may be accessing clock gated registers and
cause bus errors, will report back here.

>
> drivers/net/phy/phy.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
> index d0626bf5c540..30e7c43e0d87 100644
> --- a/drivers/net/phy/phy.c
> +++ b/drivers/net/phy/phy.c
> @@ -743,12 +743,17 @@ void phy_trigger_machine(struct phy_device *phydev, bool sync)
> */
> void phy_stop_machine(struct phy_device *phydev)
> {
> + /* Run the state machine to completion */
> + flush_delayed_work(&phydev->state_queue);
> cancel_delayed_work_sync(&phydev->state_queue);
>
> mutex_lock(&phydev->lock);
> if (phydev->state > PHY_UP && phydev->state != PHY_HALTED)
> phydev->state = PHY_UP;
> mutex_unlock(&phydev->lock);
> +
> + /* Now we can run the state machine synchronously */
> + phy_state_machine(&phydev->state_queue.work);
> }
>
> /**
>


--
Florian

2017-07-26 19:53:33

by Florian Fainelli

[permalink] [raw]
Subject: Re: [PATCH net] net: phy: Run state machine to completion

On 07/26/2017 12:34 PM, Florian Fainelli wrote:
> On 07/26/2017 12:24 PM, Florian Fainelli wrote:
>> Marc reported that he was not getting the PHY library adjust_link()
>> callback function to run when calling phy_stop() + phy_disconnect()
>> which does not indeed happen because we don't make sure we flush the
>> PHYLIB delayed work and let it run to completion. We also need to have
>> a synchronous call to phy_state_machine() in order to have the state
>> machine actually act on PHY_HALTED, set the PHY device's link down, turn
>> the network device's carrier off and finally call the adjust_link()
>> function.
>>
>> Reported-by: Marc Gonzalez <[email protected]>
>> Fixes: a390d1f379cf ("phylib: convert state_queue work to delayed_work")
>> Signed-off-by: Florian Fainelli <[email protected]>
>> ---
>> David, this dates back from before the commit mentioned in Fixes but it would
>> be hard to backport to earlier kernels if we flagged the original design flaw
>> that used timers. Also, I am not clear on the timer API whether there was a way
>> to ensure timers would run to completion before they would be cancelled.
>>
>> Marc, please add your Signed-off-by tag since you contributed the second line.
>>
>> Thanks!
>
> David, please hold off before applying this, I found a corner case with
> power management where we may be accessing clock gated registers and
> cause bus errors, will report back here.

This was a downstream only problem because I was missing these two commits:

49d52e8108a21749dc2114b924c907db43358984 ("net: phy: handle state
correctly in phy_stop_machine")
d5c3d84657db57bd23ecd58b97f1c99dd42a7b80 ("net: phy: Avoid polling PHY
with PHY_IGNORE_INTERRUPTS")

This was tested with bcmgenet (PHY_IGNORE_INTERRUPT and PHY_POLL) and
with bcm_sf2 (net/dsa/slave.c), would appreciate some review/testing
from others as well.

>
>>
>> drivers/net/phy/phy.c | 5 +++++
>> 1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
>> index d0626bf5c540..30e7c43e0d87 100644
>> --- a/drivers/net/phy/phy.c
>> +++ b/drivers/net/phy/phy.c
>> @@ -743,12 +743,17 @@ void phy_trigger_machine(struct phy_device *phydev, bool sync)
>> */
>> void phy_stop_machine(struct phy_device *phydev)
>> {
>> + /* Run the state machine to completion */
>> + flush_delayed_work(&phydev->state_queue);
>> cancel_delayed_work_sync(&phydev->state_queue);
>>
>> mutex_lock(&phydev->lock);
>> if (phydev->state > PHY_UP && phydev->state != PHY_HALTED)
>> phydev->state = PHY_UP;
>> mutex_unlock(&phydev->lock);
>> +
>> + /* Now we can run the state machine synchronously */
>> + phy_state_machine(&phydev->state_queue.work);
>> }
>>
>> /**
>>
>
>


--
Florian

2017-07-28 10:57:53

by Marc Gonzalez

[permalink] [raw]
Subject: Re: [PATCH net] net: phy: Run state machine to completion

On 26/07/2017 21:24, Florian Fainelli wrote:

> Marc reported that he was not getting the PHY library adjust_link()
> callback function to run when calling phy_stop() + phy_disconnect()
> which does not indeed happen because we don't make sure we flush the
> PHYLIB delayed work and let it run to completion. We also need to have
> a synchronous call to phy_state_machine() in order to have the state
> machine actually act on PHY_HALTED, set the PHY device's link down, turn
> the network device's carrier off and finally call the adjust_link()
> function.
>
> Reported-by: Marc Gonzalez <[email protected]>
> Fixes: a390d1f379cf ("phylib: convert state_queue work to delayed_work")
> Signed-off-by: Florian Fainelli <[email protected]>
> ---
> David, this dates back from before the commit mentioned in Fixes but it would
> be hard to backport to earlier kernels if we flagged the original design flaw
> that used timers. Also, I am not clear on the timer API whether there was a way
> to ensure timers would run to completion before they would be cancelled.
>
> Marc, please add your Signed-off-by tag since you contributed the second line.
>
> Thanks!
>
> drivers/net/phy/phy.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
> index d0626bf5c540..30e7c43e0d87 100644
> --- a/drivers/net/phy/phy.c
> +++ b/drivers/net/phy/phy.c
> @@ -743,12 +743,17 @@ void phy_trigger_machine(struct phy_device *phydev, bool sync)
> */
> void phy_stop_machine(struct phy_device *phydev)
> {
> + /* Run the state machine to completion */
> + flush_delayed_work(&phydev->state_queue);
> cancel_delayed_work_sync(&phydev->state_queue);
>
> mutex_lock(&phydev->lock);
> if (phydev->state > PHY_UP && phydev->state != PHY_HALTED)
> phydev->state = PHY_UP;
> mutex_unlock(&phydev->lock);
> +
> + /* Now we can run the state machine synchronously */
> + phy_state_machine(&phydev->state_queue.work);

Hello Florian,

Sorry, I was AFK for a couple of days.

Thanks for putting the patch together!

I added dump_stack() at the top of phy_state_machine() to better
understand what's going on.

Action: set link down on the command-line

Results:

1) PHY in interrupt mode

[ 136.238889] [<c0378518>] (phy_state_machine) from [<c0378a58>] (phy_stop_machine+0x4c/0x50)
[ 136.247285] [<c0378a58>] (phy_stop_machine) from [<c0379c30>] (phy_disconnect+0x20/0x34)
[ 136.255420] [<c0379c30>] (phy_disconnect) from [<c037d984>] (nb8800_stop+0x84/0xa0)
[ 136.263118] [<c037d984>] (nb8800_stop) from [<c03f52a4>] (__dev_close_many+0x88/0xd0)
[ 136.270989] [<c03f52a4>] (__dev_close_many) from [<c03f540c>] (__dev_close+0x24/0x38)
[ 136.278862] [<c03f540c>] (__dev_close) from [<c03fdd98>] (__dev_change_flags+0x94/0x144)
[ 136.286997] [<c03fdd98>] (__dev_change_flags) from [<c03fde60>] (dev_change_flags+0x18/0x48)
[ 136.295481] [<c03fde60>] (dev_change_flags) from [<c0463350>] (devinet_ioctl+0x6e0/0x7a0)
[ 136.303702] [<c0463350>] (devinet_ioctl) from [<c04657e0>] (inet_ioctl+0x194/0x1c0)
[ 136.311400] [<c04657e0>] (inet_ioctl) from [<c03de2f8>] (sock_ioctl+0x148/0x2fc)
[ 136.318837] [<c03de2f8>] (sock_ioctl) from [<c01dbe80>] (do_vfs_ioctl+0x9c/0x8e8)
[ 136.326361] [<c01dbe80>] (do_vfs_ioctl) from [<c01dc700>] (SyS_ioctl+0x34/0x5c)
[ 136.333710] [<c01dc700>] (SyS_ioctl) from [<c01076c0>] (ret_fast_syscall+0x0/0x3c)
[ 136.341357] nb8800 26000.ethernet eth0: Link is Down

Above, phy_state_machine() is called synchronously from phy_stop_machine().


2) PHY in polling mode

[ 54.045752] CPU: 3 PID: 892 Comm: kworker/3:1 Not tainted 4.13.0-rc1 #7
[ 54.056435] Workqueue: events_power_efficient phy_state_machine
[ 54.085399] [<c0378518>] (phy_state_machine) from [<c012e404>] (process_one_work+0x1d4/0x3ec)
[ 54.093969] [<c012e404>] (process_one_work) from [<c012f250>] (worker_thread+0x268/0x554)
[ 54.102189] [<c012f250>] (worker_thread) from [<c0133fd4>] (kthread+0x108/0x138)
[ 54.109623] [<c0133fd4>] (kthread) from [<c0107778>] (ret_from_fork+0x14/0x3c)
[ 54.116918] nb8800 26000.ethernet eth0: Link is Down

[ 54.122100] CPU: 2 PID: 973 Comm: ip Not tainted 4.13.0-rc1 #7
[ 54.155001] [<c0378518>] (phy_state_machine) from [<c0378a58>] (phy_stop_machine+0x4c/0x50)
[ 54.163397] [<c0378a58>] (phy_stop_machine) from [<c0379c30>] (phy_disconnect+0x20/0x34)
[ 54.171532] [<c0379c30>] (phy_disconnect) from [<c037d984>] (nb8800_stop+0x84/0xa0)
[ 54.179231] [<c037d984>] (nb8800_stop) from [<c03f52a4>] (__dev_close_many+0x88/0xd0)
[ 54.187103] [<c03f52a4>] (__dev_close_many) from [<c03f540c>] (__dev_close+0x24/0x38)
[ 54.194975] [<c03f540c>] (__dev_close) from [<c03fdd98>] (__dev_change_flags+0x94/0x144)
[ 54.203109] [<c03fdd98>] (__dev_change_flags) from [<c03fde60>] (dev_change_flags+0x18/0x48)
[ 54.211594] [<c03fde60>] (dev_change_flags) from [<c0463350>] (devinet_ioctl+0x6e0/0x7a0)
[ 54.219816] [<c0463350>] (devinet_ioctl) from [<c04657e0>] (inet_ioctl+0x194/0x1c0)
[ 54.227513] [<c04657e0>] (inet_ioctl) from [<c03de2f8>] (sock_ioctl+0x148/0x2fc)
[ 54.234950] [<c03de2f8>] (sock_ioctl) from [<c01dbe80>] (do_vfs_ioctl+0x9c/0x8e8)
[ 54.242473] [<c01dbe80>] (do_vfs_ioctl) from [<c01dc700>] (SyS_ioctl+0x34/0x5c)
[ 54.249821] [<c01dc700>] (SyS_ioctl) from [<c01076c0>] (ret_fast_syscall+0x0/0x3c)

Above() phy_state_machine() is called twice
- first supposedly after flush_delayed_work() => calls adjust_link()
- a second time by the explicit call => probably no-op

Therefore, my reasoning is that flush_delayed_work() is
unnecessary. The explicit call to phy_state_machine() at
the end of phy_stop_machine() will handle all cases.

What do you think?

Testing without flush_delayed_work() in polling mode:

[ 58.819100] CPU: 0 PID: 968 Comm: ip Not tainted 4.13.0-rc1 #10
[ 58.852098] [<c0378518>] (phy_state_machine) from [<c0378a50>] (phy_stop_machine+0x44/0x48)
[ 58.860494] [<c0378a50>] (phy_stop_machine) from [<c0379c28>] (phy_disconnect+0x20/0x34)
[ 58.868629] [<c0379c28>] (phy_disconnect) from [<c037d97c>] (nb8800_stop+0x84/0xa0)
[ 58.876328] [<c037d97c>] (nb8800_stop) from [<c03f529c>] (__dev_close_many+0x88/0xd0)
[ 58.884198] [<c03f529c>] (__dev_close_many) from [<c03f5404>] (__dev_close+0x24/0x38)
[ 58.892071] [<c03f5404>] (__dev_close) from [<c03fdd90>] (__dev_change_flags+0x94/0x144)
[ 58.900206] [<c03fdd90>] (__dev_change_flags) from [<c03fde58>] (dev_change_flags+0x18/0x48)
[ 58.908690] [<c03fde58>] (dev_change_flags) from [<c0463348>] (devinet_ioctl+0x6e0/0x7a0)
[ 58.916911] [<c0463348>] (devinet_ioctl) from [<c04657d8>] (inet_ioctl+0x194/0x1c0)
[ 58.924608] [<c04657d8>] (inet_ioctl) from [<c03de2f0>] (sock_ioctl+0x148/0x2fc)
[ 58.932046] [<c03de2f0>] (sock_ioctl) from [<c01dbe80>] (do_vfs_ioctl+0x9c/0x8e8)
[ 58.939569] [<c01dbe80>] (do_vfs_ioctl) from [<c01dc700>] (SyS_ioctl+0x34/0x5c)
[ 58.946917] [<c01dc700>] (SyS_ioctl) from [<c01076c0>] (ret_fast_syscall+0x0/0x3c)
[ 58.954609] nb8800 26000.ethernet eth0: Link is Down

Above, the call to adjust_link() occurs from the explicit call
to phy_state_machine()

Regards.

2017-07-28 18:51:02

by Florian Fainelli

[permalink] [raw]
Subject: Re: [PATCH net] net: phy: Run state machine to completion

On 07/28/2017 03:57 AM, Marc Gonzalez wrote:
> On 26/07/2017 21:24, Florian Fainelli wrote:
>
>> Marc reported that he was not getting the PHY library adjust_link()
>> callback function to run when calling phy_stop() + phy_disconnect()
>> which does not indeed happen because we don't make sure we flush the
>> PHYLIB delayed work and let it run to completion. We also need to have
>> a synchronous call to phy_state_machine() in order to have the state
>> machine actually act on PHY_HALTED, set the PHY device's link down, turn
>> the network device's carrier off and finally call the adjust_link()
>> function.
>>
>> Reported-by: Marc Gonzalez <[email protected]>
>> Fixes: a390d1f379cf ("phylib: convert state_queue work to delayed_work")
>> Signed-off-by: Florian Fainelli <[email protected]>
>> ---
>> David, this dates back from before the commit mentioned in Fixes but it would
>> be hard to backport to earlier kernels if we flagged the original design flaw
>> that used timers. Also, I am not clear on the timer API whether there was a way
>> to ensure timers would run to completion before they would be cancelled.
>>
>> Marc, please add your Signed-off-by tag since you contributed the second line.
>>
>> Thanks!
>>
>> drivers/net/phy/phy.c | 5 +++++
>> 1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
>> index d0626bf5c540..30e7c43e0d87 100644
>> --- a/drivers/net/phy/phy.c
>> +++ b/drivers/net/phy/phy.c
>> @@ -743,12 +743,17 @@ void phy_trigger_machine(struct phy_device *phydev, bool sync)
>> */
>> void phy_stop_machine(struct phy_device *phydev)
>> {
>> + /* Run the state machine to completion */
>> + flush_delayed_work(&phydev->state_queue);
>> cancel_delayed_work_sync(&phydev->state_queue);
>>
>> mutex_lock(&phydev->lock);
>> if (phydev->state > PHY_UP && phydev->state != PHY_HALTED)
>> phydev->state = PHY_UP;
>> mutex_unlock(&phydev->lock);
>> +
>> + /* Now we can run the state machine synchronously */
>> + phy_state_machine(&phydev->state_queue.work);
>
> Hello Florian,
>
> Sorry, I was AFK for a couple of days.
>
> Thanks for putting the patch together!
>
> I added dump_stack() at the top of phy_state_machine() to better
> understand what's going on.
>
> Action: set link down on the command-line
>
> Results:
>
> 1) PHY in interrupt mode
>
> [ 136.238889] [<c0378518>] (phy_state_machine) from [<c0378a58>] (phy_stop_machine+0x4c/0x50)
> [ 136.247285] [<c0378a58>] (phy_stop_machine) from [<c0379c30>] (phy_disconnect+0x20/0x34)
> [ 136.255420] [<c0379c30>] (phy_disconnect) from [<c037d984>] (nb8800_stop+0x84/0xa0)
> [ 136.263118] [<c037d984>] (nb8800_stop) from [<c03f52a4>] (__dev_close_many+0x88/0xd0)
> [ 136.270989] [<c03f52a4>] (__dev_close_many) from [<c03f540c>] (__dev_close+0x24/0x38)
> [ 136.278862] [<c03f540c>] (__dev_close) from [<c03fdd98>] (__dev_change_flags+0x94/0x144)
> [ 136.286997] [<c03fdd98>] (__dev_change_flags) from [<c03fde60>] (dev_change_flags+0x18/0x48)
> [ 136.295481] [<c03fde60>] (dev_change_flags) from [<c0463350>] (devinet_ioctl+0x6e0/0x7a0)
> [ 136.303702] [<c0463350>] (devinet_ioctl) from [<c04657e0>] (inet_ioctl+0x194/0x1c0)
> [ 136.311400] [<c04657e0>] (inet_ioctl) from [<c03de2f8>] (sock_ioctl+0x148/0x2fc)
> [ 136.318837] [<c03de2f8>] (sock_ioctl) from [<c01dbe80>] (do_vfs_ioctl+0x9c/0x8e8)
> [ 136.326361] [<c01dbe80>] (do_vfs_ioctl) from [<c01dc700>] (SyS_ioctl+0x34/0x5c)
> [ 136.333710] [<c01dc700>] (SyS_ioctl) from [<c01076c0>] (ret_fast_syscall+0x0/0x3c)
> [ 136.341357] nb8800 26000.ethernet eth0: Link is Down
>
> Above, phy_state_machine() is called synchronously from phy_stop_machine().
>
>
> 2) PHY in polling mode
>
> [ 54.045752] CPU: 3 PID: 892 Comm: kworker/3:1 Not tainted 4.13.0-rc1 #7
> [ 54.056435] Workqueue: events_power_efficient phy_state_machine
> [ 54.085399] [<c0378518>] (phy_state_machine) from [<c012e404>] (process_one_work+0x1d4/0x3ec)
> [ 54.093969] [<c012e404>] (process_one_work) from [<c012f250>] (worker_thread+0x268/0x554)
> [ 54.102189] [<c012f250>] (worker_thread) from [<c0133fd4>] (kthread+0x108/0x138)
> [ 54.109623] [<c0133fd4>] (kthread) from [<c0107778>] (ret_from_fork+0x14/0x3c)
> [ 54.116918] nb8800 26000.ethernet eth0: Link is Down
>
> [ 54.122100] CPU: 2 PID: 973 Comm: ip Not tainted 4.13.0-rc1 #7
> [ 54.155001] [<c0378518>] (phy_state_machine) from [<c0378a58>] (phy_stop_machine+0x4c/0x50)
> [ 54.163397] [<c0378a58>] (phy_stop_machine) from [<c0379c30>] (phy_disconnect+0x20/0x34)
> [ 54.171532] [<c0379c30>] (phy_disconnect) from [<c037d984>] (nb8800_stop+0x84/0xa0)
> [ 54.179231] [<c037d984>] (nb8800_stop) from [<c03f52a4>] (__dev_close_many+0x88/0xd0)
> [ 54.187103] [<c03f52a4>] (__dev_close_many) from [<c03f540c>] (__dev_close+0x24/0x38)
> [ 54.194975] [<c03f540c>] (__dev_close) from [<c03fdd98>] (__dev_change_flags+0x94/0x144)
> [ 54.203109] [<c03fdd98>] (__dev_change_flags) from [<c03fde60>] (dev_change_flags+0x18/0x48)
> [ 54.211594] [<c03fde60>] (dev_change_flags) from [<c0463350>] (devinet_ioctl+0x6e0/0x7a0)
> [ 54.219816] [<c0463350>] (devinet_ioctl) from [<c04657e0>] (inet_ioctl+0x194/0x1c0)
> [ 54.227513] [<c04657e0>] (inet_ioctl) from [<c03de2f8>] (sock_ioctl+0x148/0x2fc)
> [ 54.234950] [<c03de2f8>] (sock_ioctl) from [<c01dbe80>] (do_vfs_ioctl+0x9c/0x8e8)
> [ 54.242473] [<c01dbe80>] (do_vfs_ioctl) from [<c01dc700>] (SyS_ioctl+0x34/0x5c)
> [ 54.249821] [<c01dc700>] (SyS_ioctl) from [<c01076c0>] (ret_fast_syscall+0x0/0x3c)
>
> Above() phy_state_machine() is called twice
> - first supposedly after flush_delayed_work() => calls adjust_link()
> - a second time by the explicit call => probably no-op
>
> Therefore, my reasoning is that flush_delayed_work() is
> unnecessary. The explicit call to phy_state_machine() at
> the end of phy_stop_machine() will handle all cases.
>
> What do you think?

You are right I also just tested PHY_POLL and PHY_IGNORE_INTERRUPT and
only the synchronous call is necessary. Will re-post a v2 shortly.

>
> Testing without flush_delayed_work() in polling mode:
>
> [ 58.819100] CPU: 0 PID: 968 Comm: ip Not tainted 4.13.0-rc1 #10
> [ 58.852098] [<c0378518>] (phy_state_machine) from [<c0378a50>] (phy_stop_machine+0x44/0x48)
> [ 58.860494] [<c0378a50>] (phy_stop_machine) from [<c0379c28>] (phy_disconnect+0x20/0x34)
> [ 58.868629] [<c0379c28>] (phy_disconnect) from [<c037d97c>] (nb8800_stop+0x84/0xa0)
> [ 58.876328] [<c037d97c>] (nb8800_stop) from [<c03f529c>] (__dev_close_many+0x88/0xd0)
> [ 58.884198] [<c03f529c>] (__dev_close_many) from [<c03f5404>] (__dev_close+0x24/0x38)
> [ 58.892071] [<c03f5404>] (__dev_close) from [<c03fdd90>] (__dev_change_flags+0x94/0x144)
> [ 58.900206] [<c03fdd90>] (__dev_change_flags) from [<c03fde58>] (dev_change_flags+0x18/0x48)
> [ 58.908690] [<c03fde58>] (dev_change_flags) from [<c0463348>] (devinet_ioctl+0x6e0/0x7a0)
> [ 58.916911] [<c0463348>] (devinet_ioctl) from [<c04657d8>] (inet_ioctl+0x194/0x1c0)
> [ 58.924608] [<c04657d8>] (inet_ioctl) from [<c03de2f0>] (sock_ioctl+0x148/0x2fc)
> [ 58.932046] [<c03de2f0>] (sock_ioctl) from [<c01dbe80>] (do_vfs_ioctl+0x9c/0x8e8)
> [ 58.939569] [<c01dbe80>] (do_vfs_ioctl) from [<c01dc700>] (SyS_ioctl+0x34/0x5c)
> [ 58.946917] [<c01dc700>] (SyS_ioctl) from [<c01076c0>] (ret_fast_syscall+0x0/0x3c)
> [ 58.954609] nb8800 26000.ethernet eth0: Link is Down
>
> Above, the call to adjust_link() occurs from the explicit call
> to phy_state_machine()
>
> Regards.
>


--
Florian