* [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier [not found] <1437008972-9140-1-git-send-email-kamal@canonical.com> @ 2015-07-16 1:08 ` Kamal Mostafa 2015-07-16 6:37 ` Duan Andy 0 siblings, 1 reply; 6+ messages in thread From: Kamal Mostafa @ 2015-07-16 1:08 UTC (permalink / raw) To: linux-arm-kernel 3.19.8-ckt4 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Damian Eppel <d.eppel@samsung.com> commit 56a94f13919c0db5958611b388e1581b4852f3c9 upstream. Whilst testing cpu hotplug events on kernel configured with DEBUG_PREEMPT and DEBUG_ATOMIC_SLEEP we get following BUG message, caused by calling request_irq() and free_irq() in the context of hotplug notification (which is in this case atomic context). [ 40.785859] CPU1: Software reset [ 40.786660] BUG: sleeping function called from invalid context at mm/slub.c:1241 [ 40.786668] in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: swapper/1 [ 40.786678] Preemption disabled at:[< (null)>] (null) [ 40.786681] [ 40.786692] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.19.0-rc4-00024-g7dca860 #36 [ 40.786698] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 40.786728] [<c0014a00>] (unwind_backtrace) from [<c0011980>] (show_stack+0x10/0x14) [ 40.786747] [<c0011980>] (show_stack) from [<c0449ba0>] (dump_stack+0x70/0xbc) [ 40.786767] [<c0449ba0>] (dump_stack) from [<c00c6124>] (kmem_cache_alloc+0xd8/0x170) [ 40.786785] [<c00c6124>] (kmem_cache_alloc) from [<c005d6f8>] (request_threaded_irq+0x64/0x128) [ 40.786804] [<c005d6f8>] (request_threaded_irq) from [<c0350b8c>] (exynos4_local_timer_setup+0xc0/0x13c) [ 40.786820] [<c0350b8c>] (exynos4_local_timer_setup) from [<c0350ca8>] (exynos4_mct_cpu_notify+0x30/0xa8) [ 40.786838] [<c0350ca8>] (exynos4_mct_cpu_notify) from [<c003b330>] (notifier_call_chain+0x44/0x84) [ 40.786857] [<c003b330>] (notifier_call_chain) from [<c0022fd4>] (__cpu_notify+0x28/0x44) [ 40.786873] [<c0022fd4>] (__cpu_notify) from [<c0013714>] (secondary_start_kernel+0xec/0x150) [ 40.786886] [<c0013714>] (secondary_start_kernel) from [<40008764>] (0x40008764) Interrupts cannot be requested/freed in the CPU_STARTING/CPU_DYING notifications which run on the hotplugged cpu with interrupts and preemption disabled. To avoid the issue, request the interrupts for all possible cpus in the boot code. The interrupts are marked NO_AUTOENABLE to avoid a racy request_irq/disable_irq() sequence. The flag prevents the request_irq() code from enabling the interrupt immediately. The interrupt is then enabled in the CPU_STARTING notifier of the hotplugged cpu and again disabled with disable_irq_nosync() in the CPU_DYING notifier. [ tglx: Massaged changelog to match the patch ] Fixes: 7114cd749a12 ("clocksource: exynos_mct: use (request/free)_irq calls for local timer registration") Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Tested-by: Marcin Jabrzyk <m.jabrzyk@samsung.com> Signed-off-by: Damian Eppel <d.eppel@samsung.com> Cc: m.szyprowski at samsung.com Cc: kyungmin.park at samsung.com Cc: daniel.lezcano at linaro.org Cc: kgene at kernel.org Cc: linux-arm-kernel at lists.infradead.org Link: http://lkml.kernel.org/r/1435324984-7328-1-git-send-email-d.eppel at samsung.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/clocksource/exynos_mct.c | 43 ++++++++++++++++++++++++++++------------ 1 file changed, 30 insertions(+), 13 deletions(-) diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c index 83564c9..c844616 100644 --- a/drivers/clocksource/exynos_mct.c +++ b/drivers/clocksource/exynos_mct.c @@ -466,15 +466,12 @@ static int exynos4_local_timer_setup(struct clock_event_device *evt) exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET); if (mct_int_type == MCT_INT_SPI) { - evt->irq = mct_irqs[MCT_L0_IRQ + cpu]; - if (request_irq(evt->irq, exynos4_mct_tick_isr, - IRQF_TIMER | IRQF_NOBALANCING, - evt->name, mevt)) { - pr_err("exynos-mct: cannot register IRQ %d\n", - evt->irq); + + if (evt->irq == -1) return -EIO; - } - irq_force_affinity(mct_irqs[MCT_L0_IRQ + cpu], cpumask_of(cpu)); + + irq_force_affinity(evt->irq, cpumask_of(cpu)); + enable_irq(evt->irq); } else { enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0); } @@ -487,10 +484,12 @@ static int exynos4_local_timer_setup(struct clock_event_device *evt) static void exynos4_local_timer_stop(struct clock_event_device *evt) { evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt); - if (mct_int_type == MCT_INT_SPI) - free_irq(evt->irq, this_cpu_ptr(&percpu_mct_tick)); - else + if (mct_int_type == MCT_INT_SPI) { + if (evt->irq != -1) + disable_irq_nosync(evt->irq); + } else { disable_percpu_irq(mct_irqs[MCT_L0_IRQ]); + } } static int exynos4_mct_cpu_notify(struct notifier_block *self, @@ -522,7 +521,7 @@ static struct notifier_block exynos4_mct_cpu_nb = { static void __init exynos4_timer_resources(struct device_node *np, void __iomem *base) { - int err; + int err, cpu; struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick); struct clk *mct_clk, *tick_clk; @@ -549,7 +548,25 @@ static void __init exynos4_timer_resources(struct device_node *np, void __iomem WARN(err, "MCT: can't request IRQ %d (%d)\n", mct_irqs[MCT_L0_IRQ], err); } else { - irq_set_affinity(mct_irqs[MCT_L0_IRQ], cpumask_of(0)); + for_each_possible_cpu(cpu) { + int mct_irq = mct_irqs[MCT_L0_IRQ + cpu]; + struct mct_clock_event_device *pcpu_mevt = + per_cpu_ptr(&percpu_mct_tick, cpu); + + pcpu_mevt->evt.irq = -1; + + irq_set_status_flags(mct_irq, IRQ_NOAUTOEN); + if (request_irq(mct_irq, + exynos4_mct_tick_isr, + IRQF_TIMER | IRQF_NOBALANCING, + pcpu_mevt->name, pcpu_mevt)) { + pr_err("exynos-mct: cannot register IRQ (cpu%d)\n", + cpu); + + continue; + } + pcpu_mevt->evt.irq = mct_irq; + } } err = register_cpu_notifier(&exynos4_mct_cpu_nb); -- 1.9.1 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier 2015-07-16 1:08 ` [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier Kamal Mostafa @ 2015-07-16 6:37 ` Duan Andy 2015-07-16 6:55 ` Krzysztof Kozlowski 0 siblings, 1 reply; 6+ messages in thread From: Duan Andy @ 2015-07-16 6:37 UTC (permalink / raw) To: linux-arm-kernel From: Kamal Mostafa <kamal@canonical.com> Sent: Thursday, July 16, 2015 9:08 AM > To: linux-kernel at vger.kernel.org; stable at vger.kernel.org; kernel- > team at lists.ubuntu.com > Cc: Kamal Mostafa; daniel.lezcano at linaro.org; kyungmin.park at samsung.com; > Damian Eppel; kgene at kernel.org; Thomas Gleixner; linux-arm- > kernel at lists.infradead.org; m.szyprowski at samsung.com > Subject: [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid > blocking calls in the cpu hotplug notifier > > 3.19.8-ckt4 -stable review patch. If anyone has any objections, please > let me know. > > ------------------ > > From: Damian Eppel <d.eppel@samsung.com> > > commit 56a94f13919c0db5958611b388e1581b4852f3c9 upstream. > > Whilst testing cpu hotplug events on kernel configured with DEBUG_PREEMPT > and DEBUG_ATOMIC_SLEEP we get following BUG message, caused by calling > request_irq() and free_irq() in the context of hotplug notification > (which is in this case atomic context). > > [ 40.785859] CPU1: Software reset > [ 40.786660] BUG: sleeping function called from invalid context at > mm/slub.c:1241 > [ 40.786668] in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: > swapper/1 > [ 40.786678] Preemption disabled at:[< (null)>] (null) > [ 40.786681] > [ 40.786692] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.19.0-rc4- > 00024-g7dca860 #36 > [ 40.786698] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) > [ 40.786728] [<c0014a00>] (unwind_backtrace) from [<c0011980>] > (show_stack+0x10/0x14) > [ 40.786747] [<c0011980>] (show_stack) from [<c0449ba0>] > (dump_stack+0x70/0xbc) > [ 40.786767] [<c0449ba0>] (dump_stack) from [<c00c6124>] > (kmem_cache_alloc+0xd8/0x170) > [ 40.786785] [<c00c6124>] (kmem_cache_alloc) from [<c005d6f8>] > (request_threaded_irq+0x64/0x128) > [ 40.786804] [<c005d6f8>] (request_threaded_irq) from [<c0350b8c>] > (exynos4_local_timer_setup+0xc0/0x13c) > [ 40.786820] [<c0350b8c>] (exynos4_local_timer_setup) from [<c0350ca8>] > (exynos4_mct_cpu_notify+0x30/0xa8) > [ 40.786838] [<c0350ca8>] (exynos4_mct_cpu_notify) from [<c003b330>] > (notifier_call_chain+0x44/0x84) > [ 40.786857] [<c003b330>] (notifier_call_chain) from [<c0022fd4>] > (__cpu_notify+0x28/0x44) > [ 40.786873] [<c0022fd4>] (__cpu_notify) from [<c0013714>] > (secondary_start_kernel+0xec/0x150) > [ 40.786886] [<c0013714>] (secondary_start_kernel) from [<40008764>] > (0x40008764) > > Interrupts cannot be requested/freed in the CPU_STARTING/CPU_DYING > notifications which run on the hotplugged cpu with interrupts and > preemption disabled. > > To avoid the issue, request the interrupts for all possible cpus in the > boot code. The interrupts are marked NO_AUTOENABLE to avoid a racy > request_irq/disable_irq() sequence. The flag prevents the > request_irq() code from enabling the interrupt immediately. > > The interrupt is then enabled in the CPU_STARTING notifier of the > hotplugged cpu and again disabled with disable_irq_nosync() in the > CPU_DYING notifier. > > [ tglx: Massaged changelog to match the patch ] > > Fixes: 7114cd749a12 ("clocksource: exynos_mct: use (request/free)_irq > calls for local timer registration") > Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> > Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> > Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> > Tested-by: Marcin Jabrzyk <m.jabrzyk@samsung.com> > Signed-off-by: Damian Eppel <d.eppel@samsung.com> > Cc: m.szyprowski at samsung.com > Cc: kyungmin.park at samsung.com > Cc: daniel.lezcano at linaro.org > Cc: kgene at kernel.org > Cc: linux-arm-kernel at lists.infradead.org > Link: http://lkml.kernel.org/r/1435324984-7328-1-git-send-email- > d.eppel at samsung.com > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Signed-off-by: Kamal Mostafa <kamal@canonical.com> > --- > drivers/clocksource/exynos_mct.c | 43 ++++++++++++++++++++++++++++------ > ------ > 1 file changed, 30 insertions(+), 13 deletions(-) > > diff --git a/drivers/clocksource/exynos_mct.c > b/drivers/clocksource/exynos_mct.c > index 83564c9..c844616 100644 > --- a/drivers/clocksource/exynos_mct.c > +++ b/drivers/clocksource/exynos_mct.c > @@ -466,15 +466,12 @@ static int exynos4_local_timer_setup(struct > clock_event_device *evt) > exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET); > > if (mct_int_type == MCT_INT_SPI) { > - evt->irq = mct_irqs[MCT_L0_IRQ + cpu]; > - if (request_irq(evt->irq, exynos4_mct_tick_isr, > - IRQF_TIMER | IRQF_NOBALANCING, > - evt->name, mevt)) { > - pr_err("exynos-mct: cannot register IRQ %d\n", > - evt->irq); > + > + if (evt->irq == -1) > return -EIO; > - } > - irq_force_affinity(mct_irqs[MCT_L0_IRQ + cpu], > cpumask_of(cpu)); > + > + irq_force_affinity(evt->irq, cpumask_of(cpu)); > + enable_irq(evt->irq); > } else { > enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0); In here, why not use enable_percpu_irq(evt->irq) ? > } > @@ -487,10 +484,12 @@ static int exynos4_local_timer_setup(struct > clock_event_device *evt) static void exynos4_local_timer_stop(struct > clock_event_device *evt) { > evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt); > - if (mct_int_type == MCT_INT_SPI) > - free_irq(evt->irq, this_cpu_ptr(&percpu_mct_tick)); > - else > + if (mct_int_type == MCT_INT_SPI) { > + if (evt->irq != -1) > + disable_irq_nosync(evt->irq); > + } else { > disable_percpu_irq(mct_irqs[MCT_L0_IRQ]); In here, why not use disable_percpu_irq(evt->irq) ? > + } > } > > static int exynos4_mct_cpu_notify(struct notifier_block *self, @@ -522,7 > +521,7 @@ static struct notifier_block exynos4_mct_cpu_nb = { > > static void __init exynos4_timer_resources(struct device_node *np, void > __iomem *base) { > - int err; > + int err, cpu; > struct mct_clock_event_device *mevt = > this_cpu_ptr(&percpu_mct_tick); > struct clk *mct_clk, *tick_clk; > > @@ -549,7 +548,25 @@ static void __init exynos4_timer_resources(struct > device_node *np, void __iomem > WARN(err, "MCT: can't request IRQ %d (%d)\n", > mct_irqs[MCT_L0_IRQ], err); > } else { > - irq_set_affinity(mct_irqs[MCT_L0_IRQ], cpumask_of(0)); > + for_each_possible_cpu(cpu) { > + int mct_irq = mct_irqs[MCT_L0_IRQ + cpu]; > + struct mct_clock_event_device *pcpu_mevt = > + per_cpu_ptr(&percpu_mct_tick, cpu); > + > + pcpu_mevt->evt.irq = -1; > + > + irq_set_status_flags(mct_irq, IRQ_NOAUTOEN); > + if (request_irq(mct_irq, > + exynos4_mct_tick_isr, > + IRQF_TIMER | IRQF_NOBALANCING, > + pcpu_mevt->name, pcpu_mevt)) { > + pr_err("exynos-mct: cannot register IRQ > (cpu%d)\n", > + cpu); > + > + continue; > + } > + pcpu_mevt->evt.irq = mct_irq; > + } > } > > err = register_cpu_notifier(&exynos4_mct_cpu_nb); > -- > 1.9.1 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier 2015-07-16 6:37 ` Duan Andy @ 2015-07-16 6:55 ` Krzysztof Kozlowski 2015-07-16 8:14 ` Duan Andy 0 siblings, 1 reply; 6+ messages in thread From: Krzysztof Kozlowski @ 2015-07-16 6:55 UTC (permalink / raw) To: linux-arm-kernel 2015-07-16 15:37 GMT+09:00 Duan Andy <fugang.duan@freescale.com>: > From: Kamal Mostafa <kamal@canonical.com> Sent: Thursday, July 16, 2015 9:08 AM >> To: linux-kernel at vger.kernel.org; stable at vger.kernel.org; kernel- >> team at lists.ubuntu.com >> Cc: Kamal Mostafa; daniel.lezcano at linaro.org; kyungmin.park at samsung.com; >> Damian Eppel; kgene at kernel.org; Thomas Gleixner; linux-arm- >> kernel at lists.infradead.org; m.szyprowski at samsung.com >> Subject: [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid >> blocking calls in the cpu hotplug notifier >> >> 3.19.8-ckt4 -stable review patch. If anyone has any objections, please >> let me know. >> >> ------------------ >> >> From: Damian Eppel <d.eppel@samsung.com> >> >> commit 56a94f13919c0db5958611b388e1581b4852f3c9 upstream. >> >> Whilst testing cpu hotplug events on kernel configured with DEBUG_PREEMPT >> and DEBUG_ATOMIC_SLEEP we get following BUG message, caused by calling >> request_irq() and free_irq() in the context of hotplug notification >> (which is in this case atomic context). >> >> [ 40.785859] CPU1: Software reset >> [ 40.786660] BUG: sleeping function called from invalid context at >> mm/slub.c:1241 >> [ 40.786668] in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: >> swapper/1 >> [ 40.786678] Preemption disabled at:[< (null)>] (null) >> [ 40.786681] >> [ 40.786692] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.19.0-rc4- >> 00024-g7dca860 #36 >> [ 40.786698] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) >> [ 40.786728] [<c0014a00>] (unwind_backtrace) from [<c0011980>] >> (show_stack+0x10/0x14) >> [ 40.786747] [<c0011980>] (show_stack) from [<c0449ba0>] >> (dump_stack+0x70/0xbc) >> [ 40.786767] [<c0449ba0>] (dump_stack) from [<c00c6124>] >> (kmem_cache_alloc+0xd8/0x170) >> [ 40.786785] [<c00c6124>] (kmem_cache_alloc) from [<c005d6f8>] >> (request_threaded_irq+0x64/0x128) >> [ 40.786804] [<c005d6f8>] (request_threaded_irq) from [<c0350b8c>] >> (exynos4_local_timer_setup+0xc0/0x13c) >> [ 40.786820] [<c0350b8c>] (exynos4_local_timer_setup) from [<c0350ca8>] >> (exynos4_mct_cpu_notify+0x30/0xa8) >> [ 40.786838] [<c0350ca8>] (exynos4_mct_cpu_notify) from [<c003b330>] >> (notifier_call_chain+0x44/0x84) >> [ 40.786857] [<c003b330>] (notifier_call_chain) from [<c0022fd4>] >> (__cpu_notify+0x28/0x44) >> [ 40.786873] [<c0022fd4>] (__cpu_notify) from [<c0013714>] >> (secondary_start_kernel+0xec/0x150) >> [ 40.786886] [<c0013714>] (secondary_start_kernel) from [<40008764>] >> (0x40008764) >> >> Interrupts cannot be requested/freed in the CPU_STARTING/CPU_DYING >> notifications which run on the hotplugged cpu with interrupts and >> preemption disabled. >> >> To avoid the issue, request the interrupts for all possible cpus in the >> boot code. The interrupts are marked NO_AUTOENABLE to avoid a racy >> request_irq/disable_irq() sequence. The flag prevents the >> request_irq() code from enabling the interrupt immediately. >> >> The interrupt is then enabled in the CPU_STARTING notifier of the >> hotplugged cpu and again disabled with disable_irq_nosync() in the >> CPU_DYING notifier. >> >> [ tglx: Massaged changelog to match the patch ] >> >> Fixes: 7114cd749a12 ("clocksource: exynos_mct: use (request/free)_irq >> calls for local timer registration") >> Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> >> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> >> Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> >> Tested-by: Marcin Jabrzyk <m.jabrzyk@samsung.com> >> Signed-off-by: Damian Eppel <d.eppel@samsung.com> >> Cc: m.szyprowski at samsung.com >> Cc: kyungmin.park at samsung.com >> Cc: daniel.lezcano at linaro.org >> Cc: kgene at kernel.org >> Cc: linux-arm-kernel at lists.infradead.org >> Link: http://lkml.kernel.org/r/1435324984-7328-1-git-send-email- >> d.eppel at samsung.com >> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> >> Signed-off-by: Kamal Mostafa <kamal@canonical.com> >> --- >> drivers/clocksource/exynos_mct.c | 43 ++++++++++++++++++++++++++++------ >> ------ >> 1 file changed, 30 insertions(+), 13 deletions(-) >> >> diff --git a/drivers/clocksource/exynos_mct.c >> b/drivers/clocksource/exynos_mct.c >> index 83564c9..c844616 100644 >> --- a/drivers/clocksource/exynos_mct.c >> +++ b/drivers/clocksource/exynos_mct.c >> @@ -466,15 +466,12 @@ static int exynos4_local_timer_setup(struct >> clock_event_device *evt) >> exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET); >> >> if (mct_int_type == MCT_INT_SPI) { >> - evt->irq = mct_irqs[MCT_L0_IRQ + cpu]; >> - if (request_irq(evt->irq, exynos4_mct_tick_isr, >> - IRQF_TIMER | IRQF_NOBALANCING, >> - evt->name, mevt)) { >> - pr_err("exynos-mct: cannot register IRQ %d\n", >> - evt->irq); >> + >> + if (evt->irq == -1) >> return -EIO; >> - } >> - irq_force_affinity(mct_irqs[MCT_L0_IRQ + cpu], >> cpumask_of(cpu)); >> + >> + irq_force_affinity(evt->irq, cpumask_of(cpu)); >> + enable_irq(evt->irq); >> } else { >> enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0); > > In here, why not use enable_percpu_irq(evt->irq) ? > >> } >> @@ -487,10 +484,12 @@ static int exynos4_local_timer_setup(struct >> clock_event_device *evt) static void exynos4_local_timer_stop(struct >> clock_event_device *evt) { >> evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt); >> - if (mct_int_type == MCT_INT_SPI) >> - free_irq(evt->irq, this_cpu_ptr(&percpu_mct_tick)); >> - else >> + if (mct_int_type == MCT_INT_SPI) { >> + if (evt->irq != -1) >> + disable_irq_nosync(evt->irq); >> + } else { >> disable_percpu_irq(mct_irqs[MCT_L0_IRQ]); > > In here, why not use disable_percpu_irq(evt->irq) ? You know this is just a semi-automatic stable backport and this was already merged to mainline? Best regards, Krzysztof ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier 2015-07-16 6:55 ` Krzysztof Kozlowski @ 2015-07-16 8:14 ` Duan Andy 2015-07-16 9:52 ` Krzysztof Kozlowski 0 siblings, 1 reply; 6+ messages in thread From: Duan Andy @ 2015-07-16 8:14 UTC (permalink / raw) To: linux-arm-kernel From: Krzysztof Kozlowski <k.kozlowski@samsung.com> Sent: Thursday, July 16, 2015 2:56 PM > To: Duan Fugang-B38611 > Cc: Kamal Mostafa; linux-kernel at vger.kernel.org; stable at vger.kernel.org; > kernel-team at lists.ubuntu.com; daniel.lezcano at linaro.org; Damian Eppel; > kyungmin.park at samsung.com; kgene at kernel.org; Thomas Gleixner; linux-arm- > kernel at lists.infradead.org; m.szyprowski at samsung.com > Subject: Re: [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid > blocking calls in the cpu hotplug notifier > > 2015-07-16 15:37 GMT+09:00 Duan Andy <fugang.duan@freescale.com>: > > From: Kamal Mostafa <kamal@canonical.com> Sent: Thursday, July 16, > > 2015 9:08 AM > >> To: linux-kernel at vger.kernel.org; stable at vger.kernel.org; kernel- > >> team at lists.ubuntu.com > >> Cc: Kamal Mostafa; daniel.lezcano at linaro.org; > >> kyungmin.park at samsung.com; Damian Eppel; kgene at kernel.org; Thomas > >> Gleixner; linux-arm- kernel at lists.infradead.org; > >> m.szyprowski at samsung.com > >> Subject: [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid > >> blocking calls in the cpu hotplug notifier > >> > >> 3.19.8-ckt4 -stable review patch. If anyone has any objections, > >> please let me know. > >> > >> ------------------ > >> > >> From: Damian Eppel <d.eppel@samsung.com> > >> > >> commit 56a94f13919c0db5958611b388e1581b4852f3c9 upstream. > >> > >> Whilst testing cpu hotplug events on kernel configured with > >> DEBUG_PREEMPT and DEBUG_ATOMIC_SLEEP we get following BUG message, > >> caused by calling > >> request_irq() and free_irq() in the context of hotplug notification > >> (which is in this case atomic context). > >> > >> [ 40.785859] CPU1: Software reset > >> [ 40.786660] BUG: sleeping function called from invalid context at > >> mm/slub.c:1241 > >> [ 40.786668] in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: > >> swapper/1 > >> [ 40.786678] Preemption disabled at:[< (null)>] (null) > >> [ 40.786681] > >> [ 40.786692] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.19.0-rc4- > >> 00024-g7dca860 #36 > >> [ 40.786698] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) > >> [ 40.786728] [<c0014a00>] (unwind_backtrace) from [<c0011980>] > >> (show_stack+0x10/0x14) > >> [ 40.786747] [<c0011980>] (show_stack) from [<c0449ba0>] > >> (dump_stack+0x70/0xbc) > >> [ 40.786767] [<c0449ba0>] (dump_stack) from [<c00c6124>] > >> (kmem_cache_alloc+0xd8/0x170) > >> [ 40.786785] [<c00c6124>] (kmem_cache_alloc) from [<c005d6f8>] > >> (request_threaded_irq+0x64/0x128) > >> [ 40.786804] [<c005d6f8>] (request_threaded_irq) from [<c0350b8c>] > >> (exynos4_local_timer_setup+0xc0/0x13c) > >> [ 40.786820] [<c0350b8c>] (exynos4_local_timer_setup) from > [<c0350ca8>] > >> (exynos4_mct_cpu_notify+0x30/0xa8) > >> [ 40.786838] [<c0350ca8>] (exynos4_mct_cpu_notify) from [<c003b330>] > >> (notifier_call_chain+0x44/0x84) > >> [ 40.786857] [<c003b330>] (notifier_call_chain) from [<c0022fd4>] > >> (__cpu_notify+0x28/0x44) > >> [ 40.786873] [<c0022fd4>] (__cpu_notify) from [<c0013714>] > >> (secondary_start_kernel+0xec/0x150) > >> [ 40.786886] [<c0013714>] (secondary_start_kernel) from [<40008764>] > >> (0x40008764) > >> > >> Interrupts cannot be requested/freed in the CPU_STARTING/CPU_DYING > >> notifications which run on the hotplugged cpu with interrupts and > >> preemption disabled. > >> > >> To avoid the issue, request the interrupts for all possible cpus in > >> the boot code. The interrupts are marked NO_AUTOENABLE to avoid a > >> racy > >> request_irq/disable_irq() sequence. The flag prevents the > >> request_irq() code from enabling the interrupt immediately. > >> > >> The interrupt is then enabled in the CPU_STARTING notifier of the > >> hotplugged cpu and again disabled with disable_irq_nosync() in the > >> CPU_DYING notifier. > >> > >> [ tglx: Massaged changelog to match the patch ] > >> > >> Fixes: 7114cd749a12 ("clocksource: exynos_mct: use (request/free)_irq > >> calls for local timer registration") > >> Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> > >> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> > >> Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> > >> Tested-by: Marcin Jabrzyk <m.jabrzyk@samsung.com> > >> Signed-off-by: Damian Eppel <d.eppel@samsung.com> > >> Cc: m.szyprowski at samsung.com > >> Cc: kyungmin.park at samsung.com > >> Cc: daniel.lezcano at linaro.org > >> Cc: kgene at kernel.org > >> Cc: linux-arm-kernel at lists.infradead.org > >> Link: http://lkml.kernel.org/r/1435324984-7328-1-git-send-email- > >> d.eppel at samsung.com > >> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > >> Signed-off-by: Kamal Mostafa <kamal@canonical.com> > >> --- > >> drivers/clocksource/exynos_mct.c | 43 > >> ++++++++++++++++++++++++++++------ > >> ------ > >> 1 file changed, 30 insertions(+), 13 deletions(-) > >> > >> diff --git a/drivers/clocksource/exynos_mct.c > >> b/drivers/clocksource/exynos_mct.c > >> index 83564c9..c844616 100644 > >> --- a/drivers/clocksource/exynos_mct.c > >> +++ b/drivers/clocksource/exynos_mct.c > >> @@ -466,15 +466,12 @@ static int exynos4_local_timer_setup(struct > >> clock_event_device *evt) > >> exynos4_mct_write(TICK_BASE_CNT, mevt->base + > >> MCT_L_TCNTB_OFFSET); > >> > >> if (mct_int_type == MCT_INT_SPI) { > >> - evt->irq = mct_irqs[MCT_L0_IRQ + cpu]; > >> - if (request_irq(evt->irq, exynos4_mct_tick_isr, > >> - IRQF_TIMER | IRQF_NOBALANCING, > >> - evt->name, mevt)) { > >> - pr_err("exynos-mct: cannot register IRQ %d\n", > >> - evt->irq); > >> + > >> + if (evt->irq == -1) > >> return -EIO; > >> - } > >> - irq_force_affinity(mct_irqs[MCT_L0_IRQ + cpu], > >> cpumask_of(cpu)); > >> + > >> + irq_force_affinity(evt->irq, cpumask_of(cpu)); > >> + enable_irq(evt->irq); > >> } else { > >> enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0); > > > > In here, why not use enable_percpu_irq(evt->irq) ? > > > >> } > >> @@ -487,10 +484,12 @@ static int exynos4_local_timer_setup(struct > >> clock_event_device *evt) static void exynos4_local_timer_stop(struct > >> clock_event_device *evt) { > >> evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt); > >> - if (mct_int_type == MCT_INT_SPI) > >> - free_irq(evt->irq, this_cpu_ptr(&percpu_mct_tick)); > >> - else > >> + if (mct_int_type == MCT_INT_SPI) { > >> + if (evt->irq != -1) > >> + disable_irq_nosync(evt->irq); > >> + } else { > >> disable_percpu_irq(mct_irqs[MCT_L0_IRQ]); > > > > In here, why not use disable_percpu_irq(evt->irq) ? > > You know this is just a semi-automatic stable backport and this was > already merged to mainline? > > Best regards, > Krzysztof Yes, I know. Do you know the reason why not enable other cpus irq ? I want to confirm whether it is right after below change ? enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0); -> enable_percpu_irq(evt->irq, 0); disable_percpu_irq(mct_irqs[MCT_L0_IRQ]) -> disable_percpu_irq(evt->irq) Regards, Andy ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier 2015-07-16 8:14 ` Duan Andy @ 2015-07-16 9:52 ` Krzysztof Kozlowski 2015-07-17 1:29 ` Duan Andy 0 siblings, 1 reply; 6+ messages in thread From: Krzysztof Kozlowski @ 2015-07-16 9:52 UTC (permalink / raw) To: linux-arm-kernel 2015-07-16 17:14 GMT+09:00 Duan Andy <fugang.duan@freescale.com>: > From: Krzysztof Kozlowski <k.kozlowski@samsung.com> Sent: Thursday, July 16, 2015 2:56 PM >> To: Duan Fugang-B38611 >> Cc: Kamal Mostafa; linux-kernel at vger.kernel.org; stable at vger.kernel.org; >> kernel-team at lists.ubuntu.com; daniel.lezcano at linaro.org; Damian Eppel; >> kyungmin.park at samsung.com; kgene at kernel.org; Thomas Gleixner; linux-arm- >> kernel at lists.infradead.org; m.szyprowski at samsung.com >> Subject: Re: [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid >> blocking calls in the cpu hotplug notifier >> >> 2015-07-16 15:37 GMT+09:00 Duan Andy <fugang.duan@freescale.com>: >> > From: Kamal Mostafa <kamal@canonical.com> Sent: Thursday, July 16, >> > 2015 9:08 AM >> >> To: linux-kernel at vger.kernel.org; stable at vger.kernel.org; kernel- >> >> team at lists.ubuntu.com >> >> Cc: Kamal Mostafa; daniel.lezcano at linaro.org; >> >> kyungmin.park at samsung.com; Damian Eppel; kgene at kernel.org; Thomas >> >> Gleixner; linux-arm- kernel at lists.infradead.org; >> >> m.szyprowski at samsung.com >> >> Subject: [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid >> >> blocking calls in the cpu hotplug notifier >> >> >> >> 3.19.8-ckt4 -stable review patch. If anyone has any objections, >> >> please let me know. >> >> >> >> ------------------ >> >> >> >> From: Damian Eppel <d.eppel@samsung.com> >> >> >> >> commit 56a94f13919c0db5958611b388e1581b4852f3c9 upstream. >> >> >> >> Whilst testing cpu hotplug events on kernel configured with >> >> DEBUG_PREEMPT and DEBUG_ATOMIC_SLEEP we get following BUG message, >> >> caused by calling >> >> request_irq() and free_irq() in the context of hotplug notification >> >> (which is in this case atomic context). >> >> >> >> [ 40.785859] CPU1: Software reset >> >> [ 40.786660] BUG: sleeping function called from invalid context at >> >> mm/slub.c:1241 >> >> [ 40.786668] in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: >> >> swapper/1 >> >> [ 40.786678] Preemption disabled at:[< (null)>] (null) >> >> [ 40.786681] >> >> [ 40.786692] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.19.0-rc4- >> >> 00024-g7dca860 #36 >> >> [ 40.786698] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) >> >> [ 40.786728] [<c0014a00>] (unwind_backtrace) from [<c0011980>] >> >> (show_stack+0x10/0x14) >> >> [ 40.786747] [<c0011980>] (show_stack) from [<c0449ba0>] >> >> (dump_stack+0x70/0xbc) >> >> [ 40.786767] [<c0449ba0>] (dump_stack) from [<c00c6124>] >> >> (kmem_cache_alloc+0xd8/0x170) >> >> [ 40.786785] [<c00c6124>] (kmem_cache_alloc) from [<c005d6f8>] >> >> (request_threaded_irq+0x64/0x128) >> >> [ 40.786804] [<c005d6f8>] (request_threaded_irq) from [<c0350b8c>] >> >> (exynos4_local_timer_setup+0xc0/0x13c) >> >> [ 40.786820] [<c0350b8c>] (exynos4_local_timer_setup) from >> [<c0350ca8>] >> >> (exynos4_mct_cpu_notify+0x30/0xa8) >> >> [ 40.786838] [<c0350ca8>] (exynos4_mct_cpu_notify) from [<c003b330>] >> >> (notifier_call_chain+0x44/0x84) >> >> [ 40.786857] [<c003b330>] (notifier_call_chain) from [<c0022fd4>] >> >> (__cpu_notify+0x28/0x44) >> >> [ 40.786873] [<c0022fd4>] (__cpu_notify) from [<c0013714>] >> >> (secondary_start_kernel+0xec/0x150) >> >> [ 40.786886] [<c0013714>] (secondary_start_kernel) from [<40008764>] >> >> (0x40008764) >> >> >> >> Interrupts cannot be requested/freed in the CPU_STARTING/CPU_DYING >> >> notifications which run on the hotplugged cpu with interrupts and >> >> preemption disabled. >> >> >> >> To avoid the issue, request the interrupts for all possible cpus in >> >> the boot code. The interrupts are marked NO_AUTOENABLE to avoid a >> >> racy >> >> request_irq/disable_irq() sequence. The flag prevents the >> >> request_irq() code from enabling the interrupt immediately. >> >> >> >> The interrupt is then enabled in the CPU_STARTING notifier of the >> >> hotplugged cpu and again disabled with disable_irq_nosync() in the >> >> CPU_DYING notifier. >> >> >> >> [ tglx: Massaged changelog to match the patch ] >> >> >> >> Fixes: 7114cd749a12 ("clocksource: exynos_mct: use (request/free)_irq >> >> calls for local timer registration") >> >> Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> >> >> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> >> >> Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> >> >> Tested-by: Marcin Jabrzyk <m.jabrzyk@samsung.com> >> >> Signed-off-by: Damian Eppel <d.eppel@samsung.com> >> >> Cc: m.szyprowski at samsung.com >> >> Cc: kyungmin.park at samsung.com >> >> Cc: daniel.lezcano at linaro.org >> >> Cc: kgene at kernel.org >> >> Cc: linux-arm-kernel at lists.infradead.org >> >> Link: http://lkml.kernel.org/r/1435324984-7328-1-git-send-email- >> >> d.eppel at samsung.com >> >> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> >> >> Signed-off-by: Kamal Mostafa <kamal@canonical.com> >> >> --- >> >> drivers/clocksource/exynos_mct.c | 43 >> >> ++++++++++++++++++++++++++++------ >> >> ------ >> >> 1 file changed, 30 insertions(+), 13 deletions(-) >> >> >> >> diff --git a/drivers/clocksource/exynos_mct.c >> >> b/drivers/clocksource/exynos_mct.c >> >> index 83564c9..c844616 100644 >> >> --- a/drivers/clocksource/exynos_mct.c >> >> +++ b/drivers/clocksource/exynos_mct.c >> >> @@ -466,15 +466,12 @@ static int exynos4_local_timer_setup(struct >> >> clock_event_device *evt) >> >> exynos4_mct_write(TICK_BASE_CNT, mevt->base + >> >> MCT_L_TCNTB_OFFSET); >> >> >> >> if (mct_int_type == MCT_INT_SPI) { >> >> - evt->irq = mct_irqs[MCT_L0_IRQ + cpu]; >> >> - if (request_irq(evt->irq, exynos4_mct_tick_isr, >> >> - IRQF_TIMER | IRQF_NOBALANCING, >> >> - evt->name, mevt)) { >> >> - pr_err("exynos-mct: cannot register IRQ %d\n", >> >> - evt->irq); >> >> + >> >> + if (evt->irq == -1) >> >> return -EIO; >> >> - } >> >> - irq_force_affinity(mct_irqs[MCT_L0_IRQ + cpu], >> >> cpumask_of(cpu)); >> >> + >> >> + irq_force_affinity(evt->irq, cpumask_of(cpu)); >> >> + enable_irq(evt->irq); >> >> } else { >> >> enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0); >> > >> > In here, why not use enable_percpu_irq(evt->irq) ? >> > >> >> } >> >> @@ -487,10 +484,12 @@ static int exynos4_local_timer_setup(struct >> >> clock_event_device *evt) static void exynos4_local_timer_stop(struct >> >> clock_event_device *evt) { >> >> evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt); >> >> - if (mct_int_type == MCT_INT_SPI) >> >> - free_irq(evt->irq, this_cpu_ptr(&percpu_mct_tick)); >> >> - else >> >> + if (mct_int_type == MCT_INT_SPI) { >> >> + if (evt->irq != -1) >> >> + disable_irq_nosync(evt->irq); >> >> + } else { >> >> disable_percpu_irq(mct_irqs[MCT_L0_IRQ]); >> > >> > In here, why not use disable_percpu_irq(evt->irq) ? >> >> You know this is just a semi-automatic stable backport and this was >> already merged to mainline? >> >> Best regards, >> Krzysztof > > Yes, I know. Do you know the reason why not enable other cpus irq ? > I want to confirm whether it is right after below change ? > enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0); -> enable_percpu_irq(evt->irq, 0); > disable_percpu_irq(mct_irqs[MCT_L0_IRQ]) -> disable_percpu_irq(evt->irq) This is a backport so are there any objections about this patch? Do you think the patch is invalid so it should not be backported to stable? Best regards, Krzysztof ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier 2015-07-16 9:52 ` Krzysztof Kozlowski @ 2015-07-17 1:29 ` Duan Andy 0 siblings, 0 replies; 6+ messages in thread From: Duan Andy @ 2015-07-17 1:29 UTC (permalink / raw) To: linux-arm-kernel From: Krzysztof Kozlowski <k.kozlowski@samsung.com> Sent: Thursday, July 16, 2015 5:52 PM > To: Duan Fugang-B38611 > Cc: Krzysztof Kozlowski; Kamal Mostafa; daniel.lezcano at linaro.org; linux- > kernel at vger.kernel.org; stable at vger.kernel.org; Damian Eppel; > kgene at kernel.org; kyungmin.park at samsung.com; Thomas Gleixner; > m.szyprowski at samsung.com; linux-arm-kernel at lists.infradead.org; kernel- > team at lists.ubuntu.com > Subject: Re: [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid > blocking calls in the cpu hotplug notifier > > 2015-07-16 17:14 GMT+09:00 Duan Andy <fugang.duan@freescale.com>: > > From: Krzysztof Kozlowski <k.kozlowski@samsung.com> Sent: Thursday, > > July 16, 2015 2:56 PM > >> To: Duan Fugang-B38611 > >> Cc: Kamal Mostafa; linux-kernel at vger.kernel.org; > >> stable at vger.kernel.org; kernel-team at lists.ubuntu.com; > >> daniel.lezcano at linaro.org; Damian Eppel; kyungmin.park at samsung.com; > >> kgene at kernel.org; Thomas Gleixner; linux-arm- > >> kernel at lists.infradead.org; m.szyprowski at samsung.com > >> Subject: Re: [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: > >> Avoid blocking calls in the cpu hotplug notifier > >> > >> 2015-07-16 15:37 GMT+09:00 Duan Andy <fugang.duan@freescale.com>: > >> > From: Kamal Mostafa <kamal@canonical.com> Sent: Thursday, July 16, > >> > 2015 9:08 AM > >> >> To: linux-kernel at vger.kernel.org; stable at vger.kernel.org; kernel- > >> >> team at lists.ubuntu.com > >> >> Cc: Kamal Mostafa; daniel.lezcano at linaro.org; > >> >> kyungmin.park at samsung.com; Damian Eppel; kgene at kernel.org; Thomas > >> >> Gleixner; linux-arm- kernel at lists.infradead.org; > >> >> m.szyprowski at samsung.com > >> >> Subject: [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid > >> >> blocking calls in the cpu hotplug notifier > >> >> > >> >> 3.19.8-ckt4 -stable review patch. If anyone has any objections, > >> >> please let me know. > >> >> > >> >> ------------------ > >> >> > >> >> From: Damian Eppel <d.eppel@samsung.com> > >> >> > >> >> commit 56a94f13919c0db5958611b388e1581b4852f3c9 upstream. > >> >> > >> >> Whilst testing cpu hotplug events on kernel configured with > >> >> DEBUG_PREEMPT and DEBUG_ATOMIC_SLEEP we get following BUG message, > >> >> caused by calling > >> >> request_irq() and free_irq() in the context of hotplug > >> >> notification (which is in this case atomic context). > >> >> > >> >> [ 40.785859] CPU1: Software reset > >> >> [ 40.786660] BUG: sleeping function called from invalid context > at > >> >> mm/slub.c:1241 > >> >> [ 40.786668] in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: > >> >> swapper/1 > >> >> [ 40.786678] Preemption disabled at:[< (null)>] (null) > >> >> [ 40.786681] > >> >> [ 40.786692] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.19.0- > rc4- > >> >> 00024-g7dca860 #36 > >> >> [ 40.786698] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) > >> >> [ 40.786728] [<c0014a00>] (unwind_backtrace) from [<c0011980>] > >> >> (show_stack+0x10/0x14) > >> >> [ 40.786747] [<c0011980>] (show_stack) from [<c0449ba0>] > >> >> (dump_stack+0x70/0xbc) > >> >> [ 40.786767] [<c0449ba0>] (dump_stack) from [<c00c6124>] > >> >> (kmem_cache_alloc+0xd8/0x170) > >> >> [ 40.786785] [<c00c6124>] (kmem_cache_alloc) from [<c005d6f8>] > >> >> (request_threaded_irq+0x64/0x128) > >> >> [ 40.786804] [<c005d6f8>] (request_threaded_irq) from [<c0350b8c>] > >> >> (exynos4_local_timer_setup+0xc0/0x13c) > >> >> [ 40.786820] [<c0350b8c>] (exynos4_local_timer_setup) from > >> [<c0350ca8>] > >> >> (exynos4_mct_cpu_notify+0x30/0xa8) > >> >> [ 40.786838] [<c0350ca8>] (exynos4_mct_cpu_notify) from > [<c003b330>] > >> >> (notifier_call_chain+0x44/0x84) > >> >> [ 40.786857] [<c003b330>] (notifier_call_chain) from [<c0022fd4>] > >> >> (__cpu_notify+0x28/0x44) > >> >> [ 40.786873] [<c0022fd4>] (__cpu_notify) from [<c0013714>] > >> >> (secondary_start_kernel+0xec/0x150) > >> >> [ 40.786886] [<c0013714>] (secondary_start_kernel) from > [<40008764>] > >> >> (0x40008764) > >> >> > >> >> Interrupts cannot be requested/freed in the CPU_STARTING/CPU_DYING > >> >> notifications which run on the hotplugged cpu with interrupts and > >> >> preemption disabled. > >> >> > >> >> To avoid the issue, request the interrupts for all possible cpus > >> >> in the boot code. The interrupts are marked NO_AUTOENABLE to avoid > >> >> a racy > >> >> request_irq/disable_irq() sequence. The flag prevents the > >> >> request_irq() code from enabling the interrupt immediately. > >> >> > >> >> The interrupt is then enabled in the CPU_STARTING notifier of the > >> >> hotplugged cpu and again disabled with disable_irq_nosync() in the > >> >> CPU_DYING notifier. > >> >> > >> >> [ tglx: Massaged changelog to match the patch ] > >> >> > >> >> Fixes: 7114cd749a12 ("clocksource: exynos_mct: use > >> >> (request/free)_irq calls for local timer registration") > >> >> Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> > >> >> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> > >> >> Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> > >> >> Tested-by: Marcin Jabrzyk <m.jabrzyk@samsung.com> > >> >> Signed-off-by: Damian Eppel <d.eppel@samsung.com> > >> >> Cc: m.szyprowski at samsung.com > >> >> Cc: kyungmin.park at samsung.com > >> >> Cc: daniel.lezcano at linaro.org > >> >> Cc: kgene at kernel.org > >> >> Cc: linux-arm-kernel at lists.infradead.org > >> >> Link: http://lkml.kernel.org/r/1435324984-7328-1-git-send-email- > >> >> d.eppel at samsung.com > >> >> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > >> >> Signed-off-by: Kamal Mostafa <kamal@canonical.com> > >> >> --- > >> >> drivers/clocksource/exynos_mct.c | 43 > >> >> ++++++++++++++++++++++++++++------ > >> >> ------ > >> >> 1 file changed, 30 insertions(+), 13 deletions(-) > >> >> > >> >> diff --git a/drivers/clocksource/exynos_mct.c > >> >> b/drivers/clocksource/exynos_mct.c > >> >> index 83564c9..c844616 100644 > >> >> --- a/drivers/clocksource/exynos_mct.c > >> >> +++ b/drivers/clocksource/exynos_mct.c > >> >> @@ -466,15 +466,12 @@ static int exynos4_local_timer_setup(struct > >> >> clock_event_device *evt) > >> >> exynos4_mct_write(TICK_BASE_CNT, mevt->base + > >> >> MCT_L_TCNTB_OFFSET); > >> >> > >> >> if (mct_int_type == MCT_INT_SPI) { > >> >> - evt->irq = mct_irqs[MCT_L0_IRQ + cpu]; > >> >> - if (request_irq(evt->irq, exynos4_mct_tick_isr, > >> >> - IRQF_TIMER | IRQF_NOBALANCING, > >> >> - evt->name, mevt)) { > >> >> - pr_err("exynos-mct: cannot register IRQ %d\n", > >> >> - evt->irq); > >> >> + > >> >> + if (evt->irq == -1) > >> >> return -EIO; > >> >> - } > >> >> - irq_force_affinity(mct_irqs[MCT_L0_IRQ + cpu], > >> >> cpumask_of(cpu)); > >> >> + > >> >> + irq_force_affinity(evt->irq, cpumask_of(cpu)); > >> >> + enable_irq(evt->irq); > >> >> } else { > >> >> enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0); > >> > > >> > In here, why not use enable_percpu_irq(evt->irq) ? > >> > > >> >> } > >> >> @@ -487,10 +484,12 @@ static int exynos4_local_timer_setup(struct > >> >> clock_event_device *evt) static void > >> >> exynos4_local_timer_stop(struct clock_event_device *evt) { > >> >> evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt); > >> >> - if (mct_int_type == MCT_INT_SPI) > >> >> - free_irq(evt->irq, this_cpu_ptr(&percpu_mct_tick)); > >> >> - else > >> >> + if (mct_int_type == MCT_INT_SPI) { > >> >> + if (evt->irq != -1) > >> >> + disable_irq_nosync(evt->irq); > >> >> + } else { > >> >> disable_percpu_irq(mct_irqs[MCT_L0_IRQ]); > >> > > >> > In here, why not use disable_percpu_irq(evt->irq) ? > >> > >> You know this is just a semi-automatic stable backport and this was > >> already merged to mainline? > >> > >> Best regards, > >> Krzysztof > > > > Yes, I know. Do you know the reason why not enable other cpus irq ? > > I want to confirm whether it is right after below change ? > > enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0); -> > > enable_percpu_irq(evt->irq, 0); > > disable_percpu_irq(mct_irqs[MCT_L0_IRQ]) -> > > disable_percpu_irq(evt->irq) > > This is a backport so are there any objections about this patch? Do you > think the patch is invalid so it should not be backported to stable? > No, I just have some questions about the original code design. Your patch has no problem. Regards, Andy ^ permalink raw reply [flat|nested] 6+ messages in thread
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[not found] <1437008972-9140-1-git-send-email-kamal@canonical.com>
2015-07-16 1:08 ` [PATCH 3.19.y-ckt 173/251] clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier Kamal Mostafa
2015-07-16 6:37 ` Duan Andy
2015-07-16 6:55 ` Krzysztof Kozlowski
2015-07-16 8:14 ` Duan Andy
2015-07-16 9:52 ` Krzysztof Kozlowski
2015-07-17 1:29 ` Duan Andy
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