| Message ID | 20200329142109.1501-1-cai@lca.pw (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | [v2] x86/acpi: fix a deadlock with cpu hotplug | expand |
On Sunday, March 29, 2020 4:21:09 PM CEST Qian Cai wrote: > Similar to the commit 0266d81e9bf5 ("acpi/processor: Prevent cpu hotplug > deadlock") except this is for acpi_processor_ffh_cstate_probe(): > > "The problem is that the work is scheduled on the current CPU from the > hotplug thread associated with that CPU. > > It's not required to invoke these functions via the workqueue because > the hotplug thread runs on the target CPU already. > > Check whether current is a per cpu thread pinned on the target CPU and > invoke the function directly to avoid the workqueue." > > Since CONFIG_ACPI_PROCESSOR (for cstate.c) selects > CONFIG_ACPI_CPU_FREQ_PSS (for processor_throttling.c) on x86, just > make call_on_cpu() a static inline function from processor_throttling.c > and use it in cstate.c. > > WARNING: possible circular locking dependency detected > ------------------------------------------------------ > cpuhp/1/15 is trying to acquire lock: > ffffc90003447a28 ((work_completion)(&wfc.work)){+.+.}-{0:0}, at: __flush_work+0x4c6/0x630 > > but task is already holding lock: > ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20 > > which lock already depends on the new lock. > > the existing dependency chain (in reverse order) is: > > -> #1 (cpu_hotplug_lock){++++}-{0:0}: > cpus_read_lock+0x3e/0xc0 > irq_calc_affinity_vectors+0x5f/0x91 > __pci_enable_msix_range+0x10f/0x9a0 > pci_alloc_irq_vectors_affinity+0x13e/0x1f0 > pci_alloc_irq_vectors_affinity at drivers/pci/msi.c:1208 > pqi_ctrl_init+0x72f/0x1618 [smartpqi] > pqi_pci_probe.cold.63+0x882/0x892 [smartpqi] > local_pci_probe+0x7a/0xc0 > work_for_cpu_fn+0x2e/0x50 > process_one_work+0x57e/0xb90 > worker_thread+0x363/0x5b0 > kthread+0x1f4/0x220 > ret_from_fork+0x27/0x50 > > -> #0 ((work_completion)(&wfc.work)){+.+.}-{0:0}: > __lock_acquire+0x2244/0x32a0 > lock_acquire+0x1a2/0x680 > __flush_work+0x4e6/0x630 > work_on_cpu+0x114/0x160 > acpi_processor_ffh_cstate_probe+0x129/0x250 > acpi_processor_evaluate_cst+0x4c8/0x580 > acpi_processor_get_power_info+0x86/0x740 > acpi_processor_hotplug+0xc3/0x140 > acpi_soft_cpu_online+0x102/0x1d0 > cpuhp_invoke_callback+0x197/0x1120 > cpuhp_thread_fun+0x252/0x2f0 > smpboot_thread_fn+0x255/0x440 > kthread+0x1f4/0x220 > ret_from_fork+0x27/0x50 > > other info that might help us debug this: > > Chain exists of: > (work_completion)(&wfc.work) --> cpuhp_state-up --> cpuidle_lock > > Possible unsafe locking scenario: > > CPU0 CPU1 > ---- ---- > lock(cpuidle_lock); > lock(cpuhp_state-up); > lock(cpuidle_lock); > lock((work_completion)(&wfc.work)); > > *** DEADLOCK *** > > 3 locks held by cpuhp/1/15: > #0: ffffffffaf51ab10 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0 > #1: ffffffffaf51ad40 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0 > #2: ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20 > > Call Trace: > dump_stack+0xa0/0xea > print_circular_bug.cold.52+0x147/0x14c > check_noncircular+0x295/0x2d0 > __lock_acquire+0x2244/0x32a0 > lock_acquire+0x1a2/0x680 > __flush_work+0x4e6/0x630 > work_on_cpu+0x114/0x160 > acpi_processor_ffh_cstate_probe+0x129/0x250 > acpi_processor_evaluate_cst+0x4c8/0x580 > acpi_processor_get_power_info+0x86/0x740 > acpi_processor_hotplug+0xc3/0x140 > acpi_soft_cpu_online+0x102/0x1d0 > cpuhp_invoke_callback+0x197/0x1120 > cpuhp_thread_fun+0x252/0x2f0 > smpboot_thread_fn+0x255/0x440 > kthread+0x1f4/0x220 > ret_from_fork+0x27/0x50 > > Signed-off-by: Qian Cai <cai@lca.pw> > --- > > v2: > Make call_on_cpu() a static inline function to avoid a compilation > error when ACPI_PROCESSOR=m thanks to lkp@intel.com. > > arch/x86/kernel/acpi/cstate.c | 3 ++- > drivers/acpi/processor_throttling.c | 7 ------- > include/acpi/processor.h | 10 ++++++++++ > 3 files changed, 12 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c > index caf2edccbad2..49ae4e1ac9cd 100644 > --- a/arch/x86/kernel/acpi/cstate.c > +++ b/arch/x86/kernel/acpi/cstate.c > @@ -161,7 +161,8 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu, > > /* Make sure we are running on right CPU */ > > - retval = work_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx); > + retval = call_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx, > + false); > if (retval == 0) { > /* Use the hint in CST */ > percpu_entry->states[cx->index].eax = cx->address; > diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c > index 532a1ae3595a..a0bd56ece3ff 100644 > --- a/drivers/acpi/processor_throttling.c > +++ b/drivers/acpi/processor_throttling.c > @@ -897,13 +897,6 @@ static long __acpi_processor_get_throttling(void *data) > return pr->throttling.acpi_processor_get_throttling(pr); > } > > -static int call_on_cpu(int cpu, long (*fn)(void *), void *arg, bool direct) > -{ > - if (direct || (is_percpu_thread() && cpu == smp_processor_id())) > - return fn(arg); > - return work_on_cpu(cpu, fn, arg); > -} > - > static int acpi_processor_get_throttling(struct acpi_processor *pr) > { > if (!pr) > diff --git a/include/acpi/processor.h b/include/acpi/processor.h > index 47805172e73d..770d226b22f2 100644 > --- a/include/acpi/processor.h > +++ b/include/acpi/processor.h > @@ -297,6 +297,16 @@ static inline void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx > } > #endif > > +#ifdef CONFIG_ACPI_CPU_FREQ_PSS Why does this depend on CONFIG_ACPI_CPU_FREQ_PSS? > +static inline int call_on_cpu(int cpu, long (*fn)(void *), void *arg, > + bool direct) > +{ > + if (direct || (is_percpu_thread() && cpu == smp_processor_id())) > + return fn(arg); > + return work_on_cpu(cpu, fn, arg); > +} > +#endif > + > /* in processor_perflib.c */ > > #ifdef CONFIG_CPU_FREQ >
> On Apr 3, 2020, at 5:29 AM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > > On Sunday, March 29, 2020 4:21:09 PM CEST Qian Cai wrote: >> Similar to the commit 0266d81e9bf5 ("acpi/processor: Prevent cpu hotplug >> deadlock") except this is for acpi_processor_ffh_cstate_probe(): >> >> "The problem is that the work is scheduled on the current CPU from the >> hotplug thread associated with that CPU. >> >> It's not required to invoke these functions via the workqueue because >> the hotplug thread runs on the target CPU already. >> >> Check whether current is a per cpu thread pinned on the target CPU and >> invoke the function directly to avoid the workqueue." >> >> Since CONFIG_ACPI_PROCESSOR (for cstate.c) selects >> CONFIG_ACPI_CPU_FREQ_PSS (for processor_throttling.c) on x86, just >> make call_on_cpu() a static inline function from processor_throttling.c >> and use it in cstate.c. >> >> WARNING: possible circular locking dependency detected >> ------------------------------------------------------ >> cpuhp/1/15 is trying to acquire lock: >> ffffc90003447a28 ((work_completion)(&wfc.work)){+.+.}-{0:0}, at: __flush_work+0x4c6/0x630 >> >> but task is already holding lock: >> ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20 >> >> which lock already depends on the new lock. >> >> the existing dependency chain (in reverse order) is: >> >> -> #1 (cpu_hotplug_lock){++++}-{0:0}: >> cpus_read_lock+0x3e/0xc0 >> irq_calc_affinity_vectors+0x5f/0x91 >> __pci_enable_msix_range+0x10f/0x9a0 >> pci_alloc_irq_vectors_affinity+0x13e/0x1f0 >> pci_alloc_irq_vectors_affinity at drivers/pci/msi.c:1208 >> pqi_ctrl_init+0x72f/0x1618 [smartpqi] >> pqi_pci_probe.cold.63+0x882/0x892 [smartpqi] >> local_pci_probe+0x7a/0xc0 >> work_for_cpu_fn+0x2e/0x50 >> process_one_work+0x57e/0xb90 >> worker_thread+0x363/0x5b0 >> kthread+0x1f4/0x220 >> ret_from_fork+0x27/0x50 >> >> -> #0 ((work_completion)(&wfc.work)){+.+.}-{0:0}: >> __lock_acquire+0x2244/0x32a0 >> lock_acquire+0x1a2/0x680 >> __flush_work+0x4e6/0x630 >> work_on_cpu+0x114/0x160 >> acpi_processor_ffh_cstate_probe+0x129/0x250 >> acpi_processor_evaluate_cst+0x4c8/0x580 >> acpi_processor_get_power_info+0x86/0x740 >> acpi_processor_hotplug+0xc3/0x140 >> acpi_soft_cpu_online+0x102/0x1d0 >> cpuhp_invoke_callback+0x197/0x1120 >> cpuhp_thread_fun+0x252/0x2f0 >> smpboot_thread_fn+0x255/0x440 >> kthread+0x1f4/0x220 >> ret_from_fork+0x27/0x50 >> >> other info that might help us debug this: >> >> Chain exists of: >> (work_completion)(&wfc.work) --> cpuhp_state-up --> cpuidle_lock >> >> Possible unsafe locking scenario: >> >> CPU0 CPU1 >> ---- ---- >> lock(cpuidle_lock); >> lock(cpuhp_state-up); >> lock(cpuidle_lock); >> lock((work_completion)(&wfc.work)); >> >> *** DEADLOCK *** >> >> 3 locks held by cpuhp/1/15: >> #0: ffffffffaf51ab10 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0 >> #1: ffffffffaf51ad40 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0 >> #2: ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20 >> >> Call Trace: >> dump_stack+0xa0/0xea >> print_circular_bug.cold.52+0x147/0x14c >> check_noncircular+0x295/0x2d0 >> __lock_acquire+0x2244/0x32a0 >> lock_acquire+0x1a2/0x680 >> __flush_work+0x4e6/0x630 >> work_on_cpu+0x114/0x160 >> acpi_processor_ffh_cstate_probe+0x129/0x250 >> acpi_processor_evaluate_cst+0x4c8/0x580 >> acpi_processor_get_power_info+0x86/0x740 >> acpi_processor_hotplug+0xc3/0x140 >> acpi_soft_cpu_online+0x102/0x1d0 >> cpuhp_invoke_callback+0x197/0x1120 >> cpuhp_thread_fun+0x252/0x2f0 >> smpboot_thread_fn+0x255/0x440 >> kthread+0x1f4/0x220 >> ret_from_fork+0x27/0x50 >> >> Signed-off-by: Qian Cai <cai@lca.pw> >> --- >> >> v2: >> Make call_on_cpu() a static inline function to avoid a compilation >> error when ACPI_PROCESSOR=m thanks to lkp@intel.com. >> >> arch/x86/kernel/acpi/cstate.c | 3 ++- >> drivers/acpi/processor_throttling.c | 7 ------- >> include/acpi/processor.h | 10 ++++++++++ >> 3 files changed, 12 insertions(+), 8 deletions(-) >> >> diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c >> index caf2edccbad2..49ae4e1ac9cd 100644 >> --- a/arch/x86/kernel/acpi/cstate.c >> +++ b/arch/x86/kernel/acpi/cstate.c >> @@ -161,7 +161,8 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu, >> >> /* Make sure we are running on right CPU */ >> >> - retval = work_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx); >> + retval = call_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx, >> + false); >> if (retval == 0) { >> /* Use the hint in CST */ >> percpu_entry->states[cx->index].eax = cx->address; >> diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c >> index 532a1ae3595a..a0bd56ece3ff 100644 >> --- a/drivers/acpi/processor_throttling.c >> +++ b/drivers/acpi/processor_throttling.c >> @@ -897,13 +897,6 @@ static long __acpi_processor_get_throttling(void *data) >> return pr->throttling.acpi_processor_get_throttling(pr); >> } >> >> -static int call_on_cpu(int cpu, long (*fn)(void *), void *arg, bool direct) >> -{ >> - if (direct || (is_percpu_thread() && cpu == smp_processor_id())) >> - return fn(arg); >> - return work_on_cpu(cpu, fn, arg); >> -} >> - >> static int acpi_processor_get_throttling(struct acpi_processor *pr) >> { >> if (!pr) >> diff --git a/include/acpi/processor.h b/include/acpi/processor.h >> index 47805172e73d..770d226b22f2 100644 >> --- a/include/acpi/processor.h >> +++ b/include/acpi/processor.h >> @@ -297,6 +297,16 @@ static inline void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx >> } >> #endif >> >> +#ifdef CONFIG_ACPI_CPU_FREQ_PSS > > Why does this depend on CONFIG_ACPI_CPU_FREQ_PSS? call_on_cpu() was only used in processor_throttling.c which has, processor-$(CONFIG_ACPI_CPU_FREQ_PSS) += processor_throttling.o after this patch, it will also be used in cstate.c which has, ifneq ($(CONFIG_ACPI_PROCESSOR),) obj-y += cstate.o endif i.e., config ACPI_PROCESSOR tristate "Processor" depends on X86 || IA64 || ARM64 select ACPI_PROCESSOR_IDLE select ACPI_CPU_FREQ_PSS if X86 || IA64 Therefore, call_on_cpu() is only used when CONFIG_ACPI_CPU_FREQ_PSS=y. The #ifdef is rather a safe net that in the future, if we decided to make call_on_cpu() a non-inline function, it will prevent triggering an compilation warning for unused function when CONFIG_ACPI_CPU_FREQ_PSS=n. It may also serve as a documentation purpose to indicate that function is only used with CONFIG_ACPI_CPU_FREQ_PSS=y. > >> +static inline int call_on_cpu(int cpu, long (*fn)(void *), void *arg, >> + bool direct) >> +{ >> + if (direct || (is_percpu_thread() && cpu == smp_processor_id())) >> + return fn(arg); >> + return work_on_cpu(cpu, fn, arg); >> +} >> +#endif >> + >> /* in processor_perflib.c */ >> >> #ifdef CONFIG_CPU_FREQ
On Friday, April 3, 2020 1:18:07 PM CEST Qian Cai wrote: > > > On Apr 3, 2020, at 5:29 AM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > > > > On Sunday, March 29, 2020 4:21:09 PM CEST Qian Cai wrote: > >> Similar to the commit 0266d81e9bf5 ("acpi/processor: Prevent cpu hotplug > >> deadlock") except this is for acpi_processor_ffh_cstate_probe(): > >> > >> "The problem is that the work is scheduled on the current CPU from the > >> hotplug thread associated with that CPU. > >> > >> It's not required to invoke these functions via the workqueue because > >> the hotplug thread runs on the target CPU already. > >> > >> Check whether current is a per cpu thread pinned on the target CPU and > >> invoke the function directly to avoid the workqueue." > >> > >> Since CONFIG_ACPI_PROCESSOR (for cstate.c) selects > >> CONFIG_ACPI_CPU_FREQ_PSS (for processor_throttling.c) on x86, just > >> make call_on_cpu() a static inline function from processor_throttling.c > >> and use it in cstate.c. > >> > >> WARNING: possible circular locking dependency detected > >> ------------------------------------------------------ > >> cpuhp/1/15 is trying to acquire lock: > >> ffffc90003447a28 ((work_completion)(&wfc.work)){+.+.}-{0:0}, at: __flush_work+0x4c6/0x630 > >> > >> but task is already holding lock: > >> ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20 > >> > >> which lock already depends on the new lock. > >> > >> the existing dependency chain (in reverse order) is: > >> > >> -> #1 (cpu_hotplug_lock){++++}-{0:0}: > >> cpus_read_lock+0x3e/0xc0 > >> irq_calc_affinity_vectors+0x5f/0x91 > >> __pci_enable_msix_range+0x10f/0x9a0 > >> pci_alloc_irq_vectors_affinity+0x13e/0x1f0 > >> pci_alloc_irq_vectors_affinity at drivers/pci/msi.c:1208 > >> pqi_ctrl_init+0x72f/0x1618 [smartpqi] > >> pqi_pci_probe.cold.63+0x882/0x892 [smartpqi] > >> local_pci_probe+0x7a/0xc0 > >> work_for_cpu_fn+0x2e/0x50 > >> process_one_work+0x57e/0xb90 > >> worker_thread+0x363/0x5b0 > >> kthread+0x1f4/0x220 > >> ret_from_fork+0x27/0x50 > >> > >> -> #0 ((work_completion)(&wfc.work)){+.+.}-{0:0}: > >> __lock_acquire+0x2244/0x32a0 > >> lock_acquire+0x1a2/0x680 > >> __flush_work+0x4e6/0x630 > >> work_on_cpu+0x114/0x160 > >> acpi_processor_ffh_cstate_probe+0x129/0x250 > >> acpi_processor_evaluate_cst+0x4c8/0x580 > >> acpi_processor_get_power_info+0x86/0x740 > >> acpi_processor_hotplug+0xc3/0x140 > >> acpi_soft_cpu_online+0x102/0x1d0 > >> cpuhp_invoke_callback+0x197/0x1120 > >> cpuhp_thread_fun+0x252/0x2f0 > >> smpboot_thread_fn+0x255/0x440 > >> kthread+0x1f4/0x220 > >> ret_from_fork+0x27/0x50 > >> > >> other info that might help us debug this: > >> > >> Chain exists of: > >> (work_completion)(&wfc.work) --> cpuhp_state-up --> cpuidle_lock > >> > >> Possible unsafe locking scenario: > >> > >> CPU0 CPU1 > >> ---- ---- > >> lock(cpuidle_lock); > >> lock(cpuhp_state-up); > >> lock(cpuidle_lock); > >> lock((work_completion)(&wfc.work)); > >> > >> *** DEADLOCK *** > >> > >> 3 locks held by cpuhp/1/15: > >> #0: ffffffffaf51ab10 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0 > >> #1: ffffffffaf51ad40 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0 > >> #2: ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20 > >> > >> Call Trace: > >> dump_stack+0xa0/0xea > >> print_circular_bug.cold.52+0x147/0x14c > >> check_noncircular+0x295/0x2d0 > >> __lock_acquire+0x2244/0x32a0 > >> lock_acquire+0x1a2/0x680 > >> __flush_work+0x4e6/0x630 > >> work_on_cpu+0x114/0x160 > >> acpi_processor_ffh_cstate_probe+0x129/0x250 > >> acpi_processor_evaluate_cst+0x4c8/0x580 > >> acpi_processor_get_power_info+0x86/0x740 > >> acpi_processor_hotplug+0xc3/0x140 > >> acpi_soft_cpu_online+0x102/0x1d0 > >> cpuhp_invoke_callback+0x197/0x1120 > >> cpuhp_thread_fun+0x252/0x2f0 > >> smpboot_thread_fn+0x255/0x440 > >> kthread+0x1f4/0x220 > >> ret_from_fork+0x27/0x50 > >> > >> Signed-off-by: Qian Cai <cai@lca.pw> > >> --- > >> > >> v2: > >> Make call_on_cpu() a static inline function to avoid a compilation > >> error when ACPI_PROCESSOR=m thanks to lkp@intel.com. > >> > >> arch/x86/kernel/acpi/cstate.c | 3 ++- > >> drivers/acpi/processor_throttling.c | 7 ------- > >> include/acpi/processor.h | 10 ++++++++++ > >> 3 files changed, 12 insertions(+), 8 deletions(-) > >> > >> diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c > >> index caf2edccbad2..49ae4e1ac9cd 100644 > >> --- a/arch/x86/kernel/acpi/cstate.c > >> +++ b/arch/x86/kernel/acpi/cstate.c > >> @@ -161,7 +161,8 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu, > >> > >> /* Make sure we are running on right CPU */ > >> > >> - retval = work_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx); > >> + retval = call_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx, > >> + false); > >> if (retval == 0) { > >> /* Use the hint in CST */ > >> percpu_entry->states[cx->index].eax = cx->address; > >> diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c > >> index 532a1ae3595a..a0bd56ece3ff 100644 > >> --- a/drivers/acpi/processor_throttling.c > >> +++ b/drivers/acpi/processor_throttling.c > >> @@ -897,13 +897,6 @@ static long __acpi_processor_get_throttling(void *data) > >> return pr->throttling.acpi_processor_get_throttling(pr); > >> } > >> > >> -static int call_on_cpu(int cpu, long (*fn)(void *), void *arg, bool direct) > >> -{ > >> - if (direct || (is_percpu_thread() && cpu == smp_processor_id())) > >> - return fn(arg); > >> - return work_on_cpu(cpu, fn, arg); > >> -} > >> - > >> static int acpi_processor_get_throttling(struct acpi_processor *pr) > >> { > >> if (!pr) > >> diff --git a/include/acpi/processor.h b/include/acpi/processor.h > >> index 47805172e73d..770d226b22f2 100644 > >> --- a/include/acpi/processor.h > >> +++ b/include/acpi/processor.h > >> @@ -297,6 +297,16 @@ static inline void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx > >> } > >> #endif > >> > >> +#ifdef CONFIG_ACPI_CPU_FREQ_PSS > > > > Why does this depend on CONFIG_ACPI_CPU_FREQ_PSS? > > call_on_cpu() was only used in processor_throttling.c which has, > > processor-$(CONFIG_ACPI_CPU_FREQ_PSS) += processor_throttling.o > > after this patch, it will also be used in cstate.c which has, > > ifneq ($(CONFIG_ACPI_PROCESSOR),) > obj-y += cstate.o > endif > > i.e., > > config ACPI_PROCESSOR > tristate "Processor" > depends on X86 || IA64 || ARM64 > select ACPI_PROCESSOR_IDLE > select ACPI_CPU_FREQ_PSS if X86 || IA64 > > Therefore, call_on_cpu() is only used when CONFIG_ACPI_CPU_FREQ_PSS=y. While technically kind of correct, this is also rather far from straightforward, because cstate.o and ACPI_CPU_FREQ_PSS are different things logically. > The #ifdef is rather a safe net that in the future, if we decided to make call_on_cpu() > a non-inline function, it will prevent triggering an compilation warning for unused > function when CONFIG_ACPI_CPU_FREQ_PSS=n. But as long as it is static inline, the #ifdef isn't necessary, is it? > It may also serve as a documentation purpose to indicate that function is only used > with CONFIG_ACPI_CPU_FREQ_PSS=y. Which is incidental and therefore misleading. > > > >> +static inline int call_on_cpu(int cpu, long (*fn)(void *), void *arg, > >> + bool direct) > >> +{ > >> + if (direct || (is_percpu_thread() && cpu == smp_processor_id())) > >> + return fn(arg); > >> + return work_on_cpu(cpu, fn, arg); > >> +} > >> +#endif > >> + > >> /* in processor_perflib.c */ > >> > >> #ifdef CONFIG_CPU_FREQ >
> On Apr 3, 2020, at 9:43 AM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > > On Friday, April 3, 2020 1:18:07 PM CEST Qian Cai wrote: >> >>> On Apr 3, 2020, at 5:29 AM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: >>> >>> On Sunday, March 29, 2020 4:21:09 PM CEST Qian Cai wrote: >>>> Similar to the commit 0266d81e9bf5 ("acpi/processor: Prevent cpu hotplug >>>> deadlock") except this is for acpi_processor_ffh_cstate_probe(): >>>> >>>> "The problem is that the work is scheduled on the current CPU from the >>>> hotplug thread associated with that CPU. >>>> >>>> It's not required to invoke these functions via the workqueue because >>>> the hotplug thread runs on the target CPU already. >>>> >>>> Check whether current is a per cpu thread pinned on the target CPU and >>>> invoke the function directly to avoid the workqueue." >>>> >>>> Since CONFIG_ACPI_PROCESSOR (for cstate.c) selects >>>> CONFIG_ACPI_CPU_FREQ_PSS (for processor_throttling.c) on x86, just >>>> make call_on_cpu() a static inline function from processor_throttling.c >>>> and use it in cstate.c. >>>> >>>> WARNING: possible circular locking dependency detected >>>> ------------------------------------------------------ >>>> cpuhp/1/15 is trying to acquire lock: >>>> ffffc90003447a28 ((work_completion)(&wfc.work)){+.+.}-{0:0}, at: __flush_work+0x4c6/0x630 >>>> >>>> but task is already holding lock: >>>> ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20 >>>> >>>> which lock already depends on the new lock. >>>> >>>> the existing dependency chain (in reverse order) is: >>>> >>>> -> #1 (cpu_hotplug_lock){++++}-{0:0}: >>>> cpus_read_lock+0x3e/0xc0 >>>> irq_calc_affinity_vectors+0x5f/0x91 >>>> __pci_enable_msix_range+0x10f/0x9a0 >>>> pci_alloc_irq_vectors_affinity+0x13e/0x1f0 >>>> pci_alloc_irq_vectors_affinity at drivers/pci/msi.c:1208 >>>> pqi_ctrl_init+0x72f/0x1618 [smartpqi] >>>> pqi_pci_probe.cold.63+0x882/0x892 [smartpqi] >>>> local_pci_probe+0x7a/0xc0 >>>> work_for_cpu_fn+0x2e/0x50 >>>> process_one_work+0x57e/0xb90 >>>> worker_thread+0x363/0x5b0 >>>> kthread+0x1f4/0x220 >>>> ret_from_fork+0x27/0x50 >>>> >>>> -> #0 ((work_completion)(&wfc.work)){+.+.}-{0:0}: >>>> __lock_acquire+0x2244/0x32a0 >>>> lock_acquire+0x1a2/0x680 >>>> __flush_work+0x4e6/0x630 >>>> work_on_cpu+0x114/0x160 >>>> acpi_processor_ffh_cstate_probe+0x129/0x250 >>>> acpi_processor_evaluate_cst+0x4c8/0x580 >>>> acpi_processor_get_power_info+0x86/0x740 >>>> acpi_processor_hotplug+0xc3/0x140 >>>> acpi_soft_cpu_online+0x102/0x1d0 >>>> cpuhp_invoke_callback+0x197/0x1120 >>>> cpuhp_thread_fun+0x252/0x2f0 >>>> smpboot_thread_fn+0x255/0x440 >>>> kthread+0x1f4/0x220 >>>> ret_from_fork+0x27/0x50 >>>> >>>> other info that might help us debug this: >>>> >>>> Chain exists of: >>>> (work_completion)(&wfc.work) --> cpuhp_state-up --> cpuidle_lock >>>> >>>> Possible unsafe locking scenario: >>>> >>>> CPU0 CPU1 >>>> ---- ---- >>>> lock(cpuidle_lock); >>>> lock(cpuhp_state-up); >>>> lock(cpuidle_lock); >>>> lock((work_completion)(&wfc.work)); >>>> >>>> *** DEADLOCK *** >>>> >>>> 3 locks held by cpuhp/1/15: >>>> #0: ffffffffaf51ab10 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0 >>>> #1: ffffffffaf51ad40 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0 >>>> #2: ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20 >>>> >>>> Call Trace: >>>> dump_stack+0xa0/0xea >>>> print_circular_bug.cold.52+0x147/0x14c >>>> check_noncircular+0x295/0x2d0 >>>> __lock_acquire+0x2244/0x32a0 >>>> lock_acquire+0x1a2/0x680 >>>> __flush_work+0x4e6/0x630 >>>> work_on_cpu+0x114/0x160 >>>> acpi_processor_ffh_cstate_probe+0x129/0x250 >>>> acpi_processor_evaluate_cst+0x4c8/0x580 >>>> acpi_processor_get_power_info+0x86/0x740 >>>> acpi_processor_hotplug+0xc3/0x140 >>>> acpi_soft_cpu_online+0x102/0x1d0 >>>> cpuhp_invoke_callback+0x197/0x1120 >>>> cpuhp_thread_fun+0x252/0x2f0 >>>> smpboot_thread_fn+0x255/0x440 >>>> kthread+0x1f4/0x220 >>>> ret_from_fork+0x27/0x50 >>>> >>>> Signed-off-by: Qian Cai <cai@lca.pw> >>>> --- >>>> >>>> v2: >>>> Make call_on_cpu() a static inline function to avoid a compilation >>>> error when ACPI_PROCESSOR=m thanks to lkp@intel.com. >>>> >>>> arch/x86/kernel/acpi/cstate.c | 3 ++- >>>> drivers/acpi/processor_throttling.c | 7 ------- >>>> include/acpi/processor.h | 10 ++++++++++ >>>> 3 files changed, 12 insertions(+), 8 deletions(-) >>>> >>>> diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c >>>> index caf2edccbad2..49ae4e1ac9cd 100644 >>>> --- a/arch/x86/kernel/acpi/cstate.c >>>> +++ b/arch/x86/kernel/acpi/cstate.c >>>> @@ -161,7 +161,8 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu, >>>> >>>> /* Make sure we are running on right CPU */ >>>> >>>> - retval = work_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx); >>>> + retval = call_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx, >>>> + false); >>>> if (retval == 0) { >>>> /* Use the hint in CST */ >>>> percpu_entry->states[cx->index].eax = cx->address; >>>> diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c >>>> index 532a1ae3595a..a0bd56ece3ff 100644 >>>> --- a/drivers/acpi/processor_throttling.c >>>> +++ b/drivers/acpi/processor_throttling.c >>>> @@ -897,13 +897,6 @@ static long __acpi_processor_get_throttling(void *data) >>>> return pr->throttling.acpi_processor_get_throttling(pr); >>>> } >>>> >>>> -static int call_on_cpu(int cpu, long (*fn)(void *), void *arg, bool direct) >>>> -{ >>>> - if (direct || (is_percpu_thread() && cpu == smp_processor_id())) >>>> - return fn(arg); >>>> - return work_on_cpu(cpu, fn, arg); >>>> -} >>>> - >>>> static int acpi_processor_get_throttling(struct acpi_processor *pr) >>>> { >>>> if (!pr) >>>> diff --git a/include/acpi/processor.h b/include/acpi/processor.h >>>> index 47805172e73d..770d226b22f2 100644 >>>> --- a/include/acpi/processor.h >>>> +++ b/include/acpi/processor.h >>>> @@ -297,6 +297,16 @@ static inline void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx >>>> } >>>> #endif >>>> >>>> +#ifdef CONFIG_ACPI_CPU_FREQ_PSS >>> >>> Why does this depend on CONFIG_ACPI_CPU_FREQ_PSS? >> >> call_on_cpu() was only used in processor_throttling.c which has, >> >> processor-$(CONFIG_ACPI_CPU_FREQ_PSS) += processor_throttling.o >> >> after this patch, it will also be used in cstate.c which has, >> >> ifneq ($(CONFIG_ACPI_PROCESSOR),) >> obj-y += cstate.o >> endif >> >> i.e., >> >> config ACPI_PROCESSOR >> tristate "Processor" >> depends on X86 || IA64 || ARM64 >> select ACPI_PROCESSOR_IDLE >> select ACPI_CPU_FREQ_PSS if X86 || IA64 >> >> Therefore, call_on_cpu() is only used when CONFIG_ACPI_CPU_FREQ_PSS=y. > > While technically kind of correct, this is also rather far from straightforward, because > cstate.o and ACPI_CPU_FREQ_PSS are different things logically. > >> The #ifdef is rather a safe net that in the future, if we decided to make call_on_cpu() >> a non-inline function, it will prevent triggering an compilation warning for unused >> function when CONFIG_ACPI_CPU_FREQ_PSS=n. > > But as long as it is static inline, the #ifdef isn't necessary, is it? Yes, the compiler yet to get an ability to warn about unused inline functions. I am not going to insist for this tiny detail here. If nobody likes this #ifdef, I’ll happily remove it in v3. > >> It may also serve as a documentation purpose to indicate that function is only used >> with CONFIG_ACPI_CPU_FREQ_PSS=y. > > Which is incidental and therefore misleading. > >>> >>>> +static inline int call_on_cpu(int cpu, long (*fn)(void *), void *arg, >>>> + bool direct) >>>> +{ >>>> + if (direct || (is_percpu_thread() && cpu == smp_processor_id())) >>>> + return fn(arg); >>>> + return work_on_cpu(cpu, fn, arg); >>>> +} >>>> +#endif >>>> + >>>> /* in processor_perflib.c */ >>>> >>>> #ifdef CONFIG_CPU_FREQ
On Friday, April 3, 2020 3:47:52 PM CEST Qian Cai wrote: > > > On Apr 3, 2020, at 9:43 AM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > > > > On Friday, April 3, 2020 1:18:07 PM CEST Qian Cai wrote: > >> > >>> On Apr 3, 2020, at 5:29 AM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > >>> > >>> On Sunday, March 29, 2020 4:21:09 PM CEST Qian Cai wrote: > >>>> Similar to the commit 0266d81e9bf5 ("acpi/processor: Prevent cpu hotplug > >>>> deadlock") except this is for acpi_processor_ffh_cstate_probe(): > >>>> > >>>> "The problem is that the work is scheduled on the current CPU from the > >>>> hotplug thread associated with that CPU. > >>>> > >>>> It's not required to invoke these functions via the workqueue because > >>>> the hotplug thread runs on the target CPU already. > >>>> > >>>> Check whether current is a per cpu thread pinned on the target CPU and > >>>> invoke the function directly to avoid the workqueue." > >>>> > >>>> Since CONFIG_ACPI_PROCESSOR (for cstate.c) selects > >>>> CONFIG_ACPI_CPU_FREQ_PSS (for processor_throttling.c) on x86, just > >>>> make call_on_cpu() a static inline function from processor_throttling.c > >>>> and use it in cstate.c. > >>>> > >>>> WARNING: possible circular locking dependency detected > >>>> ------------------------------------------------------ > >>>> cpuhp/1/15 is trying to acquire lock: > >>>> ffffc90003447a28 ((work_completion)(&wfc.work)){+.+.}-{0:0}, at: __flush_work+0x4c6/0x630 > >>>> > >>>> but task is already holding lock: > >>>> ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20 > >>>> > >>>> which lock already depends on the new lock. > >>>> > >>>> the existing dependency chain (in reverse order) is: > >>>> > >>>> -> #1 (cpu_hotplug_lock){++++}-{0:0}: > >>>> cpus_read_lock+0x3e/0xc0 > >>>> irq_calc_affinity_vectors+0x5f/0x91 > >>>> __pci_enable_msix_range+0x10f/0x9a0 > >>>> pci_alloc_irq_vectors_affinity+0x13e/0x1f0 > >>>> pci_alloc_irq_vectors_affinity at drivers/pci/msi.c:1208 > >>>> pqi_ctrl_init+0x72f/0x1618 [smartpqi] > >>>> pqi_pci_probe.cold.63+0x882/0x892 [smartpqi] > >>>> local_pci_probe+0x7a/0xc0 > >>>> work_for_cpu_fn+0x2e/0x50 > >>>> process_one_work+0x57e/0xb90 > >>>> worker_thread+0x363/0x5b0 > >>>> kthread+0x1f4/0x220 > >>>> ret_from_fork+0x27/0x50 > >>>> > >>>> -> #0 ((work_completion)(&wfc.work)){+.+.}-{0:0}: > >>>> __lock_acquire+0x2244/0x32a0 > >>>> lock_acquire+0x1a2/0x680 > >>>> __flush_work+0x4e6/0x630 > >>>> work_on_cpu+0x114/0x160 > >>>> acpi_processor_ffh_cstate_probe+0x129/0x250 > >>>> acpi_processor_evaluate_cst+0x4c8/0x580 > >>>> acpi_processor_get_power_info+0x86/0x740 > >>>> acpi_processor_hotplug+0xc3/0x140 > >>>> acpi_soft_cpu_online+0x102/0x1d0 > >>>> cpuhp_invoke_callback+0x197/0x1120 > >>>> cpuhp_thread_fun+0x252/0x2f0 > >>>> smpboot_thread_fn+0x255/0x440 > >>>> kthread+0x1f4/0x220 > >>>> ret_from_fork+0x27/0x50 > >>>> > >>>> other info that might help us debug this: > >>>> > >>>> Chain exists of: > >>>> (work_completion)(&wfc.work) --> cpuhp_state-up --> cpuidle_lock > >>>> > >>>> Possible unsafe locking scenario: > >>>> > >>>> CPU0 CPU1 > >>>> ---- ---- > >>>> lock(cpuidle_lock); > >>>> lock(cpuhp_state-up); > >>>> lock(cpuidle_lock); > >>>> lock((work_completion)(&wfc.work)); > >>>> > >>>> *** DEADLOCK *** > >>>> > >>>> 3 locks held by cpuhp/1/15: > >>>> #0: ffffffffaf51ab10 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0 > >>>> #1: ffffffffaf51ad40 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0 > >>>> #2: ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20 > >>>> > >>>> Call Trace: > >>>> dump_stack+0xa0/0xea > >>>> print_circular_bug.cold.52+0x147/0x14c > >>>> check_noncircular+0x295/0x2d0 > >>>> __lock_acquire+0x2244/0x32a0 > >>>> lock_acquire+0x1a2/0x680 > >>>> __flush_work+0x4e6/0x630 > >>>> work_on_cpu+0x114/0x160 > >>>> acpi_processor_ffh_cstate_probe+0x129/0x250 > >>>> acpi_processor_evaluate_cst+0x4c8/0x580 > >>>> acpi_processor_get_power_info+0x86/0x740 > >>>> acpi_processor_hotplug+0xc3/0x140 > >>>> acpi_soft_cpu_online+0x102/0x1d0 > >>>> cpuhp_invoke_callback+0x197/0x1120 > >>>> cpuhp_thread_fun+0x252/0x2f0 > >>>> smpboot_thread_fn+0x255/0x440 > >>>> kthread+0x1f4/0x220 > >>>> ret_from_fork+0x27/0x50 > >>>> > >>>> Signed-off-by: Qian Cai <cai@lca.pw> > >>>> --- > >>>> > >>>> v2: > >>>> Make call_on_cpu() a static inline function to avoid a compilation > >>>> error when ACPI_PROCESSOR=m thanks to lkp@intel.com. > >>>> > >>>> arch/x86/kernel/acpi/cstate.c | 3 ++- > >>>> drivers/acpi/processor_throttling.c | 7 ------- > >>>> include/acpi/processor.h | 10 ++++++++++ > >>>> 3 files changed, 12 insertions(+), 8 deletions(-) > >>>> > >>>> diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c > >>>> index caf2edccbad2..49ae4e1ac9cd 100644 > >>>> --- a/arch/x86/kernel/acpi/cstate.c > >>>> +++ b/arch/x86/kernel/acpi/cstate.c > >>>> @@ -161,7 +161,8 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu, > >>>> > >>>> /* Make sure we are running on right CPU */ > >>>> > >>>> - retval = work_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx); > >>>> + retval = call_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx, > >>>> + false); > >>>> if (retval == 0) { > >>>> /* Use the hint in CST */ > >>>> percpu_entry->states[cx->index].eax = cx->address; > >>>> diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c > >>>> index 532a1ae3595a..a0bd56ece3ff 100644 > >>>> --- a/drivers/acpi/processor_throttling.c > >>>> +++ b/drivers/acpi/processor_throttling.c > >>>> @@ -897,13 +897,6 @@ static long __acpi_processor_get_throttling(void *data) > >>>> return pr->throttling.acpi_processor_get_throttling(pr); > >>>> } > >>>> > >>>> -static int call_on_cpu(int cpu, long (*fn)(void *), void *arg, bool direct) > >>>> -{ > >>>> - if (direct || (is_percpu_thread() && cpu == smp_processor_id())) > >>>> - return fn(arg); > >>>> - return work_on_cpu(cpu, fn, arg); > >>>> -} > >>>> - > >>>> static int acpi_processor_get_throttling(struct acpi_processor *pr) > >>>> { > >>>> if (!pr) > >>>> diff --git a/include/acpi/processor.h b/include/acpi/processor.h > >>>> index 47805172e73d..770d226b22f2 100644 > >>>> --- a/include/acpi/processor.h > >>>> +++ b/include/acpi/processor.h > >>>> @@ -297,6 +297,16 @@ static inline void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx > >>>> } > >>>> #endif > >>>> > >>>> +#ifdef CONFIG_ACPI_CPU_FREQ_PSS > >>> > >>> Why does this depend on CONFIG_ACPI_CPU_FREQ_PSS? > >> > >> call_on_cpu() was only used in processor_throttling.c which has, > >> > >> processor-$(CONFIG_ACPI_CPU_FREQ_PSS) += processor_throttling.o > >> > >> after this patch, it will also be used in cstate.c which has, > >> > >> ifneq ($(CONFIG_ACPI_PROCESSOR),) > >> obj-y += cstate.o > >> endif > >> > >> i.e., > >> > >> config ACPI_PROCESSOR > >> tristate "Processor" > >> depends on X86 || IA64 || ARM64 > >> select ACPI_PROCESSOR_IDLE > >> select ACPI_CPU_FREQ_PSS if X86 || IA64 > >> > >> Therefore, call_on_cpu() is only used when CONFIG_ACPI_CPU_FREQ_PSS=y. > > > > While technically kind of correct, this is also rather far from straightforward, because > > cstate.o and ACPI_CPU_FREQ_PSS are different things logically. > > > >> The #ifdef is rather a safe net that in the future, if we decided to make call_on_cpu() > >> a non-inline function, it will prevent triggering an compilation warning for unused > >> function when CONFIG_ACPI_CPU_FREQ_PSS=n. > > > > But as long as it is static inline, the #ifdef isn't necessary, is it? > > Yes, the compiler yet to get an ability to warn about unused inline functions. I am not > going to insist for this tiny detail here. If nobody likes this #ifdef, I’ll happily remove it in v3. The point is that cstate.o should rather depend on ACPI_PROCESSOR_IDLE, but that change would be orthogonal to your patch. Thanks!
diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c index caf2edccbad2..49ae4e1ac9cd 100644 --- a/arch/x86/kernel/acpi/cstate.c +++ b/arch/x86/kernel/acpi/cstate.c @@ -161,7 +161,8 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu, /* Make sure we are running on right CPU */ - retval = work_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx); + retval = call_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx, + false); if (retval == 0) { /* Use the hint in CST */ percpu_entry->states[cx->index].eax = cx->address; diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c index 532a1ae3595a..a0bd56ece3ff 100644 --- a/drivers/acpi/processor_throttling.c +++ b/drivers/acpi/processor_throttling.c @@ -897,13 +897,6 @@ static long __acpi_processor_get_throttling(void *data) return pr->throttling.acpi_processor_get_throttling(pr); } -static int call_on_cpu(int cpu, long (*fn)(void *), void *arg, bool direct) -{ - if (direct || (is_percpu_thread() && cpu == smp_processor_id())) - return fn(arg); - return work_on_cpu(cpu, fn, arg); -} - static int acpi_processor_get_throttling(struct acpi_processor *pr) { if (!pr) diff --git a/include/acpi/processor.h b/include/acpi/processor.h index 47805172e73d..770d226b22f2 100644 --- a/include/acpi/processor.h +++ b/include/acpi/processor.h @@ -297,6 +297,16 @@ static inline void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx } #endif +#ifdef CONFIG_ACPI_CPU_FREQ_PSS +static inline int call_on_cpu(int cpu, long (*fn)(void *), void *arg, + bool direct) +{ + if (direct || (is_percpu_thread() && cpu == smp_processor_id())) + return fn(arg); + return work_on_cpu(cpu, fn, arg); +} +#endif + /* in processor_perflib.c */ #ifdef CONFIG_CPU_FREQ
Similar to the commit 0266d81e9bf5 ("acpi/processor: Prevent cpu hotplug deadlock") except this is for acpi_processor_ffh_cstate_probe(): "The problem is that the work is scheduled on the current CPU from the hotplug thread associated with that CPU. It's not required to invoke these functions via the workqueue because the hotplug thread runs on the target CPU already. Check whether current is a per cpu thread pinned on the target CPU and invoke the function directly to avoid the workqueue." Since CONFIG_ACPI_PROCESSOR (for cstate.c) selects CONFIG_ACPI_CPU_FREQ_PSS (for processor_throttling.c) on x86, just make call_on_cpu() a static inline function from processor_throttling.c and use it in cstate.c. WARNING: possible circular locking dependency detected ------------------------------------------------------ cpuhp/1/15 is trying to acquire lock: ffffc90003447a28 ((work_completion)(&wfc.work)){+.+.}-{0:0}, at: __flush_work+0x4c6/0x630 but task is already holding lock: ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (cpu_hotplug_lock){++++}-{0:0}: cpus_read_lock+0x3e/0xc0 irq_calc_affinity_vectors+0x5f/0x91 __pci_enable_msix_range+0x10f/0x9a0 pci_alloc_irq_vectors_affinity+0x13e/0x1f0 pci_alloc_irq_vectors_affinity at drivers/pci/msi.c:1208 pqi_ctrl_init+0x72f/0x1618 [smartpqi] pqi_pci_probe.cold.63+0x882/0x892 [smartpqi] local_pci_probe+0x7a/0xc0 work_for_cpu_fn+0x2e/0x50 process_one_work+0x57e/0xb90 worker_thread+0x363/0x5b0 kthread+0x1f4/0x220 ret_from_fork+0x27/0x50 -> #0 ((work_completion)(&wfc.work)){+.+.}-{0:0}: __lock_acquire+0x2244/0x32a0 lock_acquire+0x1a2/0x680 __flush_work+0x4e6/0x630 work_on_cpu+0x114/0x160 acpi_processor_ffh_cstate_probe+0x129/0x250 acpi_processor_evaluate_cst+0x4c8/0x580 acpi_processor_get_power_info+0x86/0x740 acpi_processor_hotplug+0xc3/0x140 acpi_soft_cpu_online+0x102/0x1d0 cpuhp_invoke_callback+0x197/0x1120 cpuhp_thread_fun+0x252/0x2f0 smpboot_thread_fn+0x255/0x440 kthread+0x1f4/0x220 ret_from_fork+0x27/0x50 other info that might help us debug this: Chain exists of: (work_completion)(&wfc.work) --> cpuhp_state-up --> cpuidle_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(cpuidle_lock); lock(cpuhp_state-up); lock(cpuidle_lock); lock((work_completion)(&wfc.work)); *** DEADLOCK *** 3 locks held by cpuhp/1/15: #0: ffffffffaf51ab10 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0 #1: ffffffffaf51ad40 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0 #2: ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20 Call Trace: dump_stack+0xa0/0xea print_circular_bug.cold.52+0x147/0x14c check_noncircular+0x295/0x2d0 __lock_acquire+0x2244/0x32a0 lock_acquire+0x1a2/0x680 __flush_work+0x4e6/0x630 work_on_cpu+0x114/0x160 acpi_processor_ffh_cstate_probe+0x129/0x250 acpi_processor_evaluate_cst+0x4c8/0x580 acpi_processor_get_power_info+0x86/0x740 acpi_processor_hotplug+0xc3/0x140 acpi_soft_cpu_online+0x102/0x1d0 cpuhp_invoke_callback+0x197/0x1120 cpuhp_thread_fun+0x252/0x2f0 smpboot_thread_fn+0x255/0x440 kthread+0x1f4/0x220 ret_from_fork+0x27/0x50 Signed-off-by: Qian Cai <cai@lca.pw> --- v2: Make call_on_cpu() a static inline function to avoid a compilation error when ACPI_PROCESSOR=m thanks to lkp@intel.com. arch/x86/kernel/acpi/cstate.c | 3 ++- drivers/acpi/processor_throttling.c | 7 ------- include/acpi/processor.h | 10 ++++++++++ 3 files changed, 12 insertions(+), 8 deletions(-)