Re: [PATCH v1] serial: qcom-geni: Fix pinctrl deadlock on runtime resume

[Praveen Talari]

On 9/17/2025 5:43 AM, Krzysztof Kozlowski wrote:
> On 17/09/2025 02:05, Krzysztof Kozlowski wrote:
> > On 17/09/2025 19:12, Alexey Klimov wrote:
> > > Hi Praveen,
> > >
> > > On Tue Sep 16, 2025 at 4:07 PM BST, Jorge Ramirez wrote:
> > > > On 16/09/25 16:39:00, Jorge Ramirez wrote:
> > > > > On 16/09/25 12:20:25, Praveen Talari wrote:
> > > > > > Hi Alexey
> > > > > >
> > > > > > Thank you for your support.
> > > > > >
> > > > > > On 9/15/2025 7:55 PM, Praveen Talari wrote:
> > > > > > > Hi Alexey,
> > > > > > >
> > > > > > > On 9/15/2025 3:09 PM, Alexey Klimov wrote:
> > > > > > > > (removing <quic_mnaresh@xxxxxxxxxxx> from c/c -- too many mail not
> > > > > > > > delivered)
> > > > > > > >
> > > > > > > > Hi Praveen,
> > > > > > > >
> > > > > > > > On Mon Sep 15, 2025 at 7:58 AM BST, Praveen Talari wrote:
> > > > > > > > > Hi Alexey,
> > > > > > > > >
> > > > > > > > > Really appreciate you waiting!
> > > > > > > > >
> > > > > > > > > On 9/11/2025 2:30 PM, Alexey Klimov wrote:
> > > > > > > > > > Hi Praveen,
> > > > > > > > > >
> > > > > > > > > > On Thu Sep 11, 2025 at 9:34 AM BST, Praveen Talari wrote:
> > > > > > > > > > > Hi Alexy,
> > > > > > > > > > >
> > > > > > > > > > > Thank you for update.
> > > > > > > > > > >
> > > > > > > > > > > On 9/10/2025 1:35 AM, Alexey Klimov wrote:
> > > > > > > > > > > > (adding Krzysztof to c/c)
> > > > > > > > > > > >
> > > > > > > > > > > > On Mon Sep 8, 2025 at 6:43 PM BST, Alexey Klimov wrote:
> > > > > > > > > > > > > On Mon Sep 8, 2025 at 5:45 PM BST, Praveen Talari wrote:
> > > > > > > > > > > > > > A deadlock is observed in the
> > > > > > > > > > > > > > qcom_geni_serial driver during runtime
> > > > > > > > > > > > > > resume. This occurs when the pinctrl
> > > > > > > > > > > > > > subsystem reconfigures device pins
> > > > > > > > > > > > > > via msm_pinmux_set_mux() while the serial device's interrupt is an
> > > > > > > > > > > > > > active wakeup source. msm_pinmux_set_mux() calls disable_irq() or
> > > > > > > > > > > > > > __synchronize_irq(), conflicting with the active wakeup state and
> > > > > > > > > > > > > > causing the IRQ thread to enter an uninterruptible (D-state) sleep,
> > > > > > > > > > > > > > leading to system instability.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > The critical call trace leading to the deadlock is:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >         Call trace:
> > > > > > > > > > > > > >         __switch_to+0xe0/0x120
> > > > > > > > > > > > > >         __schedule+0x39c/0x978
> > > > > > > > > > > > > >         schedule+0x5c/0xf8
> > > > > > > > > > > > > >         __synchronize_irq+0x88/0xb4
> > > > > > > > > > > > > >         disable_irq+0x3c/0x4c
> > > > > > > > > > > > > >         msm_pinmux_set_mux+0x508/0x644
> > > > > > > > > > > > > >         pinmux_enable_setting+0x190/0x2dc
> > > > > > > > > > > > > >         pinctrl_commit_state+0x13c/0x208
> > > > > > > > > > > > > >         pinctrl_pm_select_default_state+0x4c/0xa4
> > > > > > > > > > > > > >         geni_se_resources_on+0xe8/0x154
> > > > > > > > > > > > > >         qcom_geni_serial_runtime_resume+0x4c/0x88
> > > > > > > > > > > > > >         pm_generic_runtime_resume+0x2c/0x44
> > > > > > > > > > > > > >         __genpd_runtime_resume+0x30/0x80
> > > > > > > > > > > > > >         genpd_runtime_resume+0x114/0x29c
> > > > > > > > > > > > > >         __rpm_callback+0x48/0x1d8
> > > > > > > > > > > > > >         rpm_callback+0x6c/0x78
> > > > > > > > > > > > > >         rpm_resume+0x530/0x750
> > > > > > > > > > > > > >         __pm_runtime_resume+0x50/0x94
> > > > > > > > > > > > > >         handle_threaded_wake_irq+0x30/0x94
> > > > > > > > > > > > > >         irq_thread_fn+0x2c/xa8
> > > > > > > > > > > > > >         irq_thread+0x160/x248
> > > > > > > > > > > > > >         kthread+0x110/x114
> > > > > > > > > > > > > >         ret_from_fork+0x10/x20
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > To resolve this, explicitly manage the wakeup IRQ state within the
> > > > > > > > > > > > > > runtime suspend/resume callbacks. In the
> > > > > > > > > > > > > > runtime resume callback, call
> > > > > > > > > > > > > > disable_irq_wake() before enabling resources. This preemptively
> > > > > > > > > > > > > > removes the "wakeup" capability from the IRQ, allowing subsequent
> > > > > > > > > > > > > > interrupt management calls to proceed
> > > > > > > > > > > > > > without conflict. An error path
> > > > > > > > > > > > > > re-enables the wakeup IRQ if resource enablement fails.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Conversely, in runtime suspend, call
> > > > > > > > > > > > > > enable_irq_wake() after resources
> > > > > > > > > > > > > > are disabled. This ensures the interrupt is configured as a wakeup
> > > > > > > > > > > > > > source only once the device has fully
> > > > > > > > > > > > > > entered its low-power state. An
> > > > > > > > > > > > > > error path handles disabling the wakeup IRQ
> > > > > > > > > > > > > > if the suspend operation
> > > > > > > > > > > > > > fails.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Fixes: 1afa70632c39 ("serial: qcom-geni:
> > > > > > > > > > > > > > Enable PM runtime for serial driver")
> > > > > > > > > > > > > > Signed-off-by: Praveen Talari <praveen.talari@xxxxxxxxxxxxxxxx>
> > > > > > > > > > > > >
> > > > > > > > > > > > > You forgot:
> > > > > > > > > > > > >
> > > > > > > > > > > > > Reported-by: Alexey Klimov <alexey.klimov@xxxxxxxxxx>
> > > > > > > > > > > > >
> > > > > > > > > > > > > Also, not sure where this change will go, via
> > > > > > > > > > > > > Greg or Jiri, but ideally
> > > > > > > > > > > > > this should be picked for current -rc cycle since regression is
> > > > > > > > > > > > > introduced during latest merge window.
> > > > > > > > > > > > >
> > > > > > > > > > > > > I also would like to test it on qrb2210 rb1 where this regression is
> > > > > > > > > > > > > reproduciable.
> > > > > >
> > > > > > Since I don't have this board, could you kindly validate the new change and
> > > > > > run a quick test on your end?
> > > > > >
> > > > > > diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c
> > > > > > b/drivers/pinctrl/qcom/pinctrl-msm.c
> > > > > > index 83eb075b6bfa..3d6601dc6fcc 100644
> > > > > > --- a/drivers/pinctrl/qcom/pinctrl-msm.c
> > > > > > +++ b/drivers/pinctrl/qcom/pinctrl-msm.c
> > > > > > @@ -215,7 +215,7 @@ static int msm_pinmux_set_mux(struct pinctrl_dev
> > > > > > *pctldev,
> > > > > >           */
> > > > > >          if (d && i != gpio_func &&
> > > > > >              !test_and_set_bit(d->hwirq, pctrl->disabled_for_mux))
> > > > > > -               disable_irq(irq);
> > > > > > +               disable_irq_nosync(irq);
> > > > > >
> > > > > >          raw_spin_lock_irqsave(&pctrl->lock, flags);
> > > > >
> > > > >
> > > > > sorry Praveen, didnt see this proposal. testing on my end as well.
> > > >
> > > > just tested on my end and all modules load - deadlocked before this
> > > > update so there is progress (now we can load the network driver)
> > >
> > > Is it supposed to be orginal patch here plus disable_irq_nosync()?
> > > Meaning changes for qcom_geni_serial_runtime_{suspend,resume}
> > > + disable_irq_nosync() in msm_pinmux_set_mux()?
> > >
> > > It seems to work here but let me know few more runs.
> >
> >
> > So this bug, after 5 weeks is still not fixed?!?

I understand the concern. We didn’t have access to the same board where 
Alexey is seeing the issue, so we tried to reproduce it on a different 
target by simulating with wake-up IRQ scenarios.

From our analysis, the issue seems to be triggered by commit 
1afa70632c39 ("serial: qcom-geni: Enable PM runtime for serial driver") 
in the pinctrl subsystem.

A fix has already been submitted, and we’re currently waiting for 
Alexey’s feedback to proceed.

> > This is just and should be reverted long time ago.
>
> I will send the revert, because this is just mocking the kernel process.
>
> Best regards,
> Krzysztof