Messages in this thread Patch in this message | | | Subject | Re: [PATCH v8 24/26] drivers: firmware: psci: Deal with CPU hotplug when using OSI mode | From | Raju P L S S S N <> | Date | Tue, 20 Nov 2018 01:20:48 +0530 |
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Hi Ulf,
Got one issue in hotplug path where of_genpd_detach_cpu calls dev_pm_qos_remove_notifier which can be sleeping as per below call stack. I think it should be applicable for current patch as well right? Please let me know what am I missing? why didn't you see this issue with this patch?
[ 8103.221387] BUG: sleeping function called from invalid context at /mnt/host/source/src/third_party/kernel/v4.14/kernel/locking/mutex.c:238 [ 8103.221455] in_atomic(): 1, irqs_disabled(): 128, pid: 11, name: migration/0 [ 8103.221487] Preemption disabled at: [ 8103.221529] [<ffffff800814dfb0>] cpu_stopper_thread+0x98/0x118 [ 8103.221600] ------------[ cut here ]------------ [ 8103.221636] kernel BUG at /mnt/host/source/src/third_party/kernel/v4.14/kernel/sched/core.c:6102! [ 8103.221678] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP [ 8103.222396] CPU: 0 PID: 11 Comm: migration/0 Tainted: G W 4.14.72 #1 [ 8103.222428] Hardware name: Google Cheza (rev1) (DT) [ 8103.222460] task: ffffffc0f842d580 task.stack: ffffff8009c18000 [ 8103.222504] PC is at ___might_sleep+0x138/0x140 [ 8103.222542] LR is at ___might_sleep+0x138/0x140 [ 8103.222577] pc : [<ffffff80080d8f04>] lr : [<ffffff80080d8f04>] pstate: 60c001c9 [ 8103.222605] sp : ffffff8009c1bb40 …. [ 8103.223924] [<ffffff80080d8f04>] ___might_sleep+0x138/0x140 [ 8103.223965] [<ffffff80080d8d98>] __might_sleep+0x4c/0x80 [ 8103.224009] [<ffffff80088e4258>] mutex_lock+0x28/0x60 [ 8103.224054] [<ffffff800850fa2c>] dev_pm_qos_remove_notifier+0x1c/0x54 [ 8103.224097] [<ffffff8008517814>] genpd_remove_device+0x3c/0x10c [ 8103.224140] [<ffffff800851949c>] genpd_dev_pm_detach+0x48/0x108 [ 8103.224183] [<ffffff80085193e0>] of_genpd_detach_cpu+0x48/0xbc [ 8103.224227] [<ffffff80083edea4>] cpu_pd_dying+0x28/0x38 [ 8103.224268] [<ffffff80080ab2c0>] cpuhp_invoke_callback+0x254/0x5f0 [ 8103.224308] [<ffffff80080acdec>] take_cpu_down+0x60/0x9c [ 8103.224346] [<ffffff800814d898>] multi_cpu_stop+0xac/0x104 [ 8103.224385] [<ffffff800814dfb8>] cpu_stopper_thread+0xa0/0x118 [ 8103.224427] [<ffffff80080cff74>] smpboot_thread_fn+0x19c/0x278 [ 8103.224472] [<ffffff80080cc0c4>] kthread+0x120/0x130 [ 8103.224513] [<ffffff8008084608>] ret_from_fork+0x10/0x18
Thanks, Raju
On 6/20/2018 10:52 PM, Ulf Hansson wrote: > To deal with CPU hotplug when OSI mode is used, the CPU device needs to be > detached from its PM domain (genpd) when putting it offline, otherwise the > CPU becomes considered as being in use from genpd and runtime PM point of > view. Obviously, then we also need to re-attach the CPU device when bring > the CPU back online, so let's do this. > > Cc: Lina Iyer <ilina@codeaurora.org> > Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> > --- > drivers/firmware/psci/psci.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c > index 700e0e995871..e649673d71f0 100644 > --- a/drivers/firmware/psci/psci.c > +++ b/drivers/firmware/psci/psci.c > @@ -190,6 +190,10 @@ static int psci_cpu_off(u32 state) > int err; > u32 fn; > > + /* If running OSI mode, detach the CPU device from its PM domain. */ > + if (psci_osi_mode_enabled) > + of_genpd_detach_cpu(smp_processor_id()); > + > fn = psci_function_id[PSCI_FN_CPU_OFF]; > err = invoke_psci_fn(fn, state, 0, 0); > return psci_to_linux_errno(err); > @@ -204,6 +208,10 @@ static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point) > err = invoke_psci_fn(fn, cpuid, entry_point, 0); > /* Clear the domain state to start fresh. */ > psci_set_domain_state(0); > + > + if (!err && psci_osi_mode_enabled) > + of_genpd_attach_cpu(cpuid); > + > return psci_to_linux_errno(err); > } > >
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