When booting an arm64 debug kernel with ACPI, I see:
BUG: sleeping function called from invalid context at mm/slab.h:420
in_atomic(): 0, irqs_disabled(): 128, pid: 12, name: cpuhp/0
1 lock held by cpuhp/0/12:
#0: (cpuhp_state-up){+.+.}, at: [<0000000057aa0dae>] cpuhp_thread_fun+0x13c/0x258
irq event stamp: 28
hardirqs last enabled at (27): [<000000000b861658>] _raw_spin_unlock_irq+0x38/0x58
hardirqs last disabled at (28): [<000000006231cfb1>] cpuhp_thread_fun+0xd0/0x258
softirqs last enabled at (0): [<0000000054d9737a>] copy_process.isra.32.part.33+0x450/0x1480
softirqs last disabled at (0): [< (null)>] (null)
CPU: 0 PID: 12 Comm: cpuhp/0 Not tainted 4.15.0+ #18
Hardware name: AppliedMicro X-Gene Mustang Board/X-Gene Mustang Board, BIOS 3.06.25 Oct 17 2016
Call trace:
dump_backtrace+0x0/0x188
show_stack+0x24/0x2c
dump_stack+0xa4/0xe0
___might_sleep+0x208/0x234
__might_sleep+0x58/0x8c
kmem_cache_alloc_trace+0x248/0x3e0
armpmu_alloc+0x38/0x1a8
arm_pmu_acpi_cpu_starting+0x11c/0x15c
cpuhp_invoke_callback+0x120/0x100c
cpuhp_thread_fun+0xe8/0x258
smpboot_thread_fn+0x170/0x268
kthread+0x110/0x13c
ret_from_fork+0x10/0x18
With commit 7d88eb695a1f ("arm/perf: Convert to hotplug state machine"),
arm_pmu uses the cpuhotplug framework to initialize the PMU driver when
using ACPI. However, the arm_pmu_acpi_cpu_starting() callback comes
before CPUHP_AP_ONLINE is reached which means it runs with interrupts
diabled and tries to allocate memory with GFP_KERNEL alloc which may
sleep.
Move CPUHP_AP_PERF_ARM_ACPI_STARTING to come after CPUHP_AP_ONLINE so
that the arm_pmu initialization runs with interrupts enabled as it
does when booting with device tree.
Fixes: 7d88eb695a1f ("arm/perf: Convert to hotplug state machine")
Signed-off-by: Mark Salter <[email protected]>
---
include/linux/cpuhotplug.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 5172ad0..e07b2da 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -114,7 +114,6 @@ enum cpuhp_state {
CPUHP_AP_ARM_VFP_STARTING,
CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING,
CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING,
- CPUHP_AP_PERF_ARM_ACPI_STARTING,
CPUHP_AP_PERF_ARM_STARTING,
CPUHP_AP_ARM_L2X0_STARTING,
CPUHP_AP_ARM_ARCH_TIMER_STARTING,
@@ -146,6 +145,7 @@ enum cpuhp_state {
CPUHP_AP_SMPBOOT_THREADS,
CPUHP_AP_X86_VDSO_VMA_ONLINE,
CPUHP_AP_IRQ_AFFINITY_ONLINE,
+ CPUHP_AP_PERF_ARM_ACPI_STARTING,
CPUHP_AP_PERF_ONLINE,
CPUHP_AP_PERF_X86_ONLINE,
CPUHP_AP_PERF_X86_UNCORE_ONLINE,
--
1.8.3.1
Hi Mark,
On Thu, Feb 08, 2018 at 12:45:04PM -0500, Mark Salter wrote:
> When booting an arm64 debug kernel with ACPI, I see:
>
> BUG: sleeping function called from invalid context at mm/slab.h:420
> in_atomic(): 0, irqs_disabled(): 128, pid: 12, name: cpuhp/0
> 1 lock held by cpuhp/0/12:
> #0: (cpuhp_state-up){+.+.}, at: [<0000000057aa0dae>] cpuhp_thread_fun+0x13c/0x258
> irq event stamp: 28
> hardirqs last enabled at (27): [<000000000b861658>] _raw_spin_unlock_irq+0x38/0x58
> hardirqs last disabled at (28): [<000000006231cfb1>] cpuhp_thread_fun+0xd0/0x258
> softirqs last enabled at (0): [<0000000054d9737a>] copy_process.isra.32.part.33+0x450/0x1480
> softirqs last disabled at (0): [< (null)>] (null)
> CPU: 0 PID: 12 Comm: cpuhp/0 Not tainted 4.15.0+ #18
> Hardware name: AppliedMicro X-Gene Mustang Board/X-Gene Mustang Board, BIOS 3.06.25 Oct 17 2016
> Call trace:
> dump_backtrace+0x0/0x188
> show_stack+0x24/0x2c
> dump_stack+0xa4/0xe0
> ___might_sleep+0x208/0x234
> __might_sleep+0x58/0x8c
> kmem_cache_alloc_trace+0x248/0x3e0
> armpmu_alloc+0x38/0x1a8
> arm_pmu_acpi_cpu_starting+0x11c/0x15c
> cpuhp_invoke_callback+0x120/0x100c
> cpuhp_thread_fun+0xe8/0x258
> smpboot_thread_fn+0x170/0x268
> kthread+0x110/0x13c
> ret_from_fork+0x10/0x18
I have patches to address this:
http://lists.infradead.org/pipermail/linux-arm-kernel/2018-February/557838.html
https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/acpi-pmu-lockdep
> With commit 7d88eb695a1f ("arm/perf: Convert to hotplug state machine"),
> arm_pmu uses the cpuhotplug framework to initialize the PMU driver when
> using ACPI. However, the arm_pmu_acpi_cpu_starting() callback comes
> before CPUHP_AP_ONLINE is reached which means it runs with interrupts
> diabled and tries to allocate memory with GFP_KERNEL alloc which may
> sleep.
>
> Move CPUHP_AP_PERF_ARM_ACPI_STARTING to come after CPUHP_AP_ONLINE so
> that the arm_pmu initialization runs with interrupts enabled as it
> does when booting with device tree.
>
> Fixes: 7d88eb695a1f ("arm/perf: Convert to hotplug state machine")
> Signed-off-by: Mark Salter <[email protected]>
> ---
> include/linux/cpuhotplug.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> index 5172ad0..e07b2da 100644
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -114,7 +114,6 @@ enum cpuhp_state {
> CPUHP_AP_ARM_VFP_STARTING,
> CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING,
> CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING,
> - CPUHP_AP_PERF_ARM_ACPI_STARTING,
> CPUHP_AP_PERF_ARM_STARTING,
> CPUHP_AP_ARM_L2X0_STARTING,
> CPUHP_AP_ARM_ARCH_TIMER_STARTING,
> @@ -146,6 +145,7 @@ enum cpuhp_state {
> CPUHP_AP_SMPBOOT_THREADS,
> CPUHP_AP_X86_VDSO_VMA_ONLINE,
> CPUHP_AP_IRQ_AFFINITY_ONLINE,
> + CPUHP_AP_PERF_ARM_ACPI_STARTING,
We need CPUHP_AP_PERF_ARM_ACPI_STARTING to happen before
CPUHP_AP_PERF_ARM_STARTING, and I think this re-ordering prevents us
from correctly resetting the PMU and enabling percpu interrupts, at
least in heterogeneous configurations (e.g. big.LITTLE systems like
Juno).
I'm not sure whether we could safely move both callbacks this late.
Thanks,
Mark.
On Thu, 2018-02-08 at 17:54 +0000, Mark Rutland wrote:
> Hi Mark,
>
> On Thu, Feb 08, 2018 at 12:45:04PM -0500, Mark Salter wrote:
> > When booting an arm64 debug kernel with ACPI, I see:
> >
> > BUG: sleeping function called from invalid context at mm/slab.h:420
> > in_atomic(): 0, irqs_disabled(): 128, pid: 12, name: cpuhp/0
> > 1 lock held by cpuhp/0/12:
> > #0: (cpuhp_state-up){+.+.}, at: [<0000000057aa0dae>] cpuhp_thread_fun+0x13c/0x258
> > irq event stamp: 28
> > hardirqs last enabled at (27): [<000000000b861658>] _raw_spin_unlock_irq+0x38/0x58
> > hardirqs last disabled at (28): [<000000006231cfb1>] cpuhp_thread_fun+0xd0/0x258
> > softirqs last enabled at (0): [<0000000054d9737a>] copy_process.isra.32.part.33+0x450/0x1480
> > softirqs last disabled at (0): [< (null)>] (null)
> > CPU: 0 PID: 12 Comm: cpuhp/0 Not tainted 4.15.0+ #18
> > Hardware name: AppliedMicro X-Gene Mustang Board/X-Gene Mustang Board, BIOS 3.06.25 Oct 17 2016
> > Call trace:
> > dump_backtrace+0x0/0x188
> > show_stack+0x24/0x2c
> > dump_stack+0xa4/0xe0
> > ___might_sleep+0x208/0x234
> > __might_sleep+0x58/0x8c
> > kmem_cache_alloc_trace+0x248/0x3e0
> > armpmu_alloc+0x38/0x1a8
> > arm_pmu_acpi_cpu_starting+0x11c/0x15c
> > cpuhp_invoke_callback+0x120/0x100c
> > cpuhp_thread_fun+0xe8/0x258
> > smpboot_thread_fn+0x170/0x268
> > kthread+0x110/0x13c
> > ret_from_fork+0x10/0x18
>
> I have patches to address this:
>
> http://lists.infradead.org/pipermail/linux-arm-kernel/2018-February/557838.html
> https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/acpi-pmu-lockdep
Awesome, I completely missed that. Thanks.
>
> > With commit 7d88eb695a1f ("arm/perf: Convert to hotplug state machine"),
> > arm_pmu uses the cpuhotplug framework to initialize the PMU driver when
> > using ACPI. However, the arm_pmu_acpi_cpu_starting() callback comes
> > before CPUHP_AP_ONLINE is reached which means it runs with interrupts
> > diabled and tries to allocate memory with GFP_KERNEL alloc which may
> > sleep.
> >
> > Move CPUHP_AP_PERF_ARM_ACPI_STARTING to come after CPUHP_AP_ONLINE so
> > that the arm_pmu initialization runs with interrupts enabled as it
> > does when booting with device tree.
> >
> > Fixes: 7d88eb695a1f ("arm/perf: Convert to hotplug state machine")
> > Signed-off-by: Mark Salter <[email protected]>
> > ---
> > include/linux/cpuhotplug.h | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> > index 5172ad0..e07b2da 100644
> > --- a/include/linux/cpuhotplug.h
> > +++ b/include/linux/cpuhotplug.h
> > @@ -114,7 +114,6 @@ enum cpuhp_state {
> > CPUHP_AP_ARM_VFP_STARTING,
> > CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING,
> > CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING,
> > - CPUHP_AP_PERF_ARM_ACPI_STARTING,
> > CPUHP_AP_PERF_ARM_STARTING,
> > CPUHP_AP_ARM_L2X0_STARTING,
> > CPUHP_AP_ARM_ARCH_TIMER_STARTING,
> > @@ -146,6 +145,7 @@ enum cpuhp_state {
> > CPUHP_AP_SMPBOOT_THREADS,
> > CPUHP_AP_X86_VDSO_VMA_ONLINE,
> > CPUHP_AP_IRQ_AFFINITY_ONLINE,
> > + CPUHP_AP_PERF_ARM_ACPI_STARTING,
>
> We need CPUHP_AP_PERF_ARM_ACPI_STARTING to happen before
> CPUHP_AP_PERF_ARM_STARTING, and I think this re-ordering prevents us
> from correctly resetting the PMU and enabling percpu interrupts, at
> least in heterogeneous configurations (e.g. big.LITTLE systems like
> Juno).
>
> I'm not sure whether we could safely move both callbacks this late.
>
> Thanks,
> Mark.
On Thu, Feb 08, 2018 at 12:58:20PM -0500, Mark Salter wrote:
> On Thu, 2018-02-08 at 17:54 +0000, Mark Rutland wrote:
> > Hi Mark,
> >
> > On Thu, Feb 08, 2018 at 12:45:04PM -0500, Mark Salter wrote:
> > > When booting an arm64 debug kernel with ACPI, I see:
> > >
> > > BUG: sleeping function called from invalid context at mm/slab.h:420
> > > in_atomic(): 0, irqs_disabled(): 128, pid: 12, name: cpuhp/0
> > > 1 lock held by cpuhp/0/12:
> > > #0: (cpuhp_state-up){+.+.}, at: [<0000000057aa0dae>] cpuhp_thread_fun+0x13c/0x258
> > > irq event stamp: 28
> > > hardirqs last enabled at (27): [<000000000b861658>] _raw_spin_unlock_irq+0x38/0x58
> > > hardirqs last disabled at (28): [<000000006231cfb1>] cpuhp_thread_fun+0xd0/0x258
> > > softirqs last enabled at (0): [<0000000054d9737a>] copy_process.isra.32.part.33+0x450/0x1480
> > > softirqs last disabled at (0): [< (null)>] (null)
> > > CPU: 0 PID: 12 Comm: cpuhp/0 Not tainted 4.15.0+ #18
> > > Hardware name: AppliedMicro X-Gene Mustang Board/X-Gene Mustang Board, BIOS 3.06.25 Oct 17 2016
> > > Call trace:
> > > dump_backtrace+0x0/0x188
> > > show_stack+0x24/0x2c
> > > dump_stack+0xa4/0xe0
> > > ___might_sleep+0x208/0x234
> > > __might_sleep+0x58/0x8c
> > > kmem_cache_alloc_trace+0x248/0x3e0
> > > armpmu_alloc+0x38/0x1a8
> > > arm_pmu_acpi_cpu_starting+0x11c/0x15c
> > > cpuhp_invoke_callback+0x120/0x100c
> > > cpuhp_thread_fun+0xe8/0x258
> > > smpboot_thread_fn+0x170/0x268
> > > kthread+0x110/0x13c
> > > ret_from_fork+0x10/0x18
> >
> > I have patches to address this:
> >
> > http://lists.infradead.org/pipermail/linux-arm-kernel/2018-February/557838.html
> > https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/acpi-pmu-lockdep
>
> Awesome, I completely missed that. Thanks.
As a heads-up, these were merged in v4.16-rc3.
Mark.