Re: [PATCH RFC tip/core/rcu] Make SRCU be once again optional

From: Paul E. McKenney
Date: Wed Jan 17 2018 - 11:47:11 EST


On Wed, Jan 17, 2018 at 11:29:26AM +0100, Arnd Bergmann wrote:
> On Wed, Jan 17, 2018 at 12:57 AM, Paul E. McKenney
> <paulmck@xxxxxxxxxxxxxxxxxx> wrote:
> > On Wed, Jan 17, 2018 at 12:03:18AM +0100, Arnd Bergmann wrote:
> >> On Tue, Jan 16, 2018 at 11:55 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> >>
> >> >
> >> > That fixed the first warning for me, doing the same thing for all three
> >> > fixed the rest
> >>
> >> Now with my workaround applied and the original randconfig that triggered
> >> the failure, I get another problem:
> >>
> >> drivers/base/power/wakeup.c:68:1: error: data definition has no type
> >> or storage class [-Werror]
> >> DEFINE_STATIC_SRCU(wakeup_srcu);
> >>
> >> Evidently there is at least one driver that uses SRCU but doesn't 'select SRCU'
> >> in Kconfig. There are probably others that just haven't been found.
> >
> > Does adding "select SRCU" on "config PM_SLEEP" in kernel/power/Kconfig
> > fix this?
>
> I'm sure it does, but the point I was making is that we probably have a number
> of those, and would never find the other ones through the current build test
> setup.
>
> I've now tried disabling a ridiculous number of options to come up with a
> setup that never enables SRCU. Interestingly, that also means we don't
> get the drivers/base/power/wakeup.c problem in 'allmodconfig', though
> I did get a link-time error:
>
> kernel/locking/lockdep.o: In function `lockdep_rcu_suspicious':
> lockdep.c:(.text+0x2704): undefined reference to `rcu_scheduler_active'
> kernel/rcu/update.o: In function `debug_lockdep_rcu_enabled':
> update.c:(.text+0x40): undefined reference to `rcu_scheduler_active'
> kernel/rcu/update.o: In function `rcu_read_lock_bh_held':
> update.c:(.text+0xa8): undefined reference to `rcu_scheduler_active'
> kernel/rcu/update.o: In function `rcu_read_lock_sched_held':
> update.c:(.text+0xce0): undefined reference to `rcu_scheduler_active'
> kernel/rcu/update.o: In function `rcu_read_lock_held':
> update.c:(.text+0xd40): undefined reference to `rcu_scheduler_active'
> kernel/rcu/update.o:update.c:(.text+0x10ac): more undefined references
> to `rcu_scheduler_active' follow
> mm/kmemleak.o: In function `kmemleak_scan':
> kmemleak.c:(.text+0x1768): undefined reference to `__end_ro_after_init'
> kmemleak.c:(.text+0x176c): undefined reference to `__start_ro_after_init'
> Makefile:1029: recipe for target 'vmlinux' failed
>
> Turning off lockdep and kmemleak gives me a working allmodconfig build.
> I'm doing some more testing on ARM, but it looks like this is a dark corner
> of the randconfig state space that I'm not sure I want to explore more.
>
> Doing an hour of randconfig builds, I already found exactly two missing
> 'select SRCU':
>
> ERROR: "__srcu_read_unlock" [drivers/infiniband/core/ib_uverbs.ko] undefined!
> drivers/base/power/wakeup.c:68:1: error: type defaults to 'int' in
> declaration of 'DEFINE_STATIC_SRCU' [-Werror=implicit-int]
>
> See below for my test patch. Without COMMON_CLK, PM_SLEEP
> and BLOCK, the number useful configurations is very limited.

Yow!!!

Not sure what to say about strange combinations of Kconfig parameters.
We could get into just as much trouble having lots of Kconfig-language
restrictions preventing these things as we could having people sometimes
randomly running into them.

Thanx, Paul

> Arnd
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 9ba8c3df9ff6..d1b0ac3c9f4d 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -91,6 +91,7 @@ config STATIC_KEYS_SELFTEST
> config OPTPROBES
> def_bool y
> depends on KPROBES && HAVE_OPTPROBES
> + depends on BROKEN || !PREEMPT
> select TASKS_RCU if PREEMPT
>
> config KPROBES_ON_FTRACE
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 3d349b4f709e..ba397fc7e9d5 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -330,7 +330,7 @@ choice
>
> config ARCH_MULTIPLATFORM
> bool "Allow multiple platforms to be selected"
> - depends on MMU
> + depends on MMU && BROKEN
> select ARM_HAS_SG_CHAIN
> select ARM_PATCH_PHYS_VIRT
> select AUTO_ZRELADDR
> @@ -345,7 +345,7 @@ config ARCH_MULTIPLATFORM
>
> config ARM_SINGLE_ARMV7M
> bool "ARMv7-M based platforms (Cortex-M0/M3/M4)"
> - depends on !MMU
> + depends on !MMU && BROKEN
> select ARM_NVIC
> select AUTO_ZRELADDR
> select TIMER_OF
> @@ -463,6 +463,7 @@ config ARCH_IXP4XX
>
> config ARCH_DOVE
> bool "Marvell Dove"
> + depends on BROKEN
> select CPU_PJ4
> select GENERIC_CLOCKEVENTS
> select GPIOLIB
> @@ -506,6 +507,7 @@ config ARCH_W90X900
>
> config ARCH_LPC32XX
> bool "NXP LPC32XX"
> + depends on BROKEN
> select ARM_AMBA
> select CLKDEV_LOOKUP
> select CLKSRC_LPC32XX
> @@ -522,6 +524,7 @@ config ARCH_LPC32XX
> config ARCH_PXA
> bool "PXA2xx/PXA3xx-based"
> depends on MMU
> + depends on BROKEN
> select ARCH_MTD_XIP
> select ARM_CPU_SUSPEND if PM
> select AUTO_ZRELADDR
> @@ -563,6 +566,7 @@ config ARCH_RPC
>
> config ARCH_SA1100
> bool "SA1100-based"
> + depends on BROKEN
> select ARCH_MTD_XIP
> select ARCH_SPARSEMEM_ENABLE
> select CLKDEV_LOOKUP
> @@ -584,6 +588,7 @@ config ARCH_SA1100
>
> config ARCH_S3C24XX
> bool "Samsung S3C24XX SoCs"
> + depends on BROKEN
> select ATAGS
> select CLKDEV_LOOKUP
> select CLKSRC_SAMSUNG_PWM
> diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
> index e2bd35b6780c..b29a10a80d97 100644
> --- a/arch/arm/kvm/Kconfig
> +++ b/arch/arm/kvm/Kconfig
> @@ -20,7 +20,7 @@ if VIRTUALIZATION
>
> config KVM
> bool "Kernel-based Virtual Machine (KVM) support"
> - depends on MMU && OF
> + depends on MMU && OF && BROKEN
> select PREEMPT_NOTIFIERS
> select ANON_INODES
> select ARM_GIC
> diff --git a/block/Kconfig b/block/Kconfig
> index 28ec55752b68..c3d807fa91b6 100644
> --- a/block/Kconfig
> +++ b/block/Kconfig
> @@ -4,6 +4,7 @@
> #
> menuconfig BLOCK
> bool "Enable the block layer" if EXPERT
> + depends on BROKEN
> default y
> select SBITMAP
> select SRCU
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> index 98ce9fc6e6c0..07fdc293134d 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -8,6 +8,7 @@ config HAVE_CLK_PREPARE
>
> config COMMON_CLK
> bool
> + depends on BROKEN
> select HAVE_CLK_PREPARE
> select CLKDEV_LOOKUP
> select SRCU
> diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
> index d8addbce40bc..244b4c241811 100644
> --- a/drivers/cpufreq/Kconfig
> +++ b/drivers/cpufreq/Kconfig
> @@ -2,6 +2,7 @@ menu "CPU Frequency scaling"
>
> config CPU_FREQ
> bool "CPU Frequency scaling"
> + depends on BROKEN
> select SRCU
> help
> CPU Frequency scaling allows you to change the clock speed of
> diff --git a/drivers/dax/Kconfig b/drivers/dax/Kconfig
> index b79aa8f7a497..efd94826c020 100644
> --- a/drivers/dax/Kconfig
> +++ b/drivers/dax/Kconfig
> @@ -1,5 +1,6 @@
> menuconfig DAX
> tristate "DAX: direct access to differentiated memory"
> + depends on BROKEN
> select SRCU
> default m if NVDIMM_DAX
>
> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
> index 6a172d338f6d..cd67f2ac8803 100644
> --- a/drivers/devfreq/Kconfig
> +++ b/drivers/devfreq/Kconfig
> @@ -1,5 +1,6 @@
> menuconfig PM_DEVFREQ
> bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support"
> + depends on BROKEN
> select SRCU
> select PM_OPP
> help
> diff --git a/drivers/gpu/drm/amd/amdgpu/Kconfig
> b/drivers/gpu/drm/amd/amdgpu/Kconfig
> index e8af1f5e8a79..20d3bcd5a638 100644
> --- a/drivers/gpu/drm/amd/amdgpu/Kconfig
> +++ b/drivers/gpu/drm/amd/amdgpu/Kconfig
> @@ -25,7 +25,7 @@ config DRM_AMDGPU_CIK
>
> config DRM_AMDGPU_USERPTR
> bool "Always enable userptr write support"
> - depends on DRM_AMDGPU
> + depends on DRM_AMDGPU && BROKEN
> select MMU_NOTIFIER
> help
> This option selects CONFIG_MMU_NOTIFIER if it isn't already
> diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
> index dfd95889f4b7..a8db7a547aab 100644
> --- a/drivers/gpu/drm/i915/Kconfig
> +++ b/drivers/gpu/drm/i915/Kconfig
> @@ -84,7 +84,7 @@ config DRM_I915_COMPRESS_ERROR
>
> config DRM_I915_USERPTR
> bool "Always enable userptr support"
> - depends on DRM_I915
> + depends on DRM_I915 && BROKEN
> select MMU_NOTIFIER
> default y
> help
> diff --git a/drivers/gpu/drm/radeon/Kconfig b/drivers/gpu/drm/radeon/Kconfig
> index 9909f5c68d76..34e1aaa60abd 100644
> --- a/drivers/gpu/drm/radeon/Kconfig
> +++ b/drivers/gpu/drm/radeon/Kconfig
> @@ -1,6 +1,6 @@
> config DRM_RADEON_USERPTR
> bool "Always enable userptr support"
> - depends on DRM_RADEON
> + depends on DRM_RADEON && BROKEN
> select MMU_NOTIFIER
> help
> This option selects CONFIG_MMU_NOTIFIER if it isn't already
> diff --git a/drivers/hwtracing/coresight/Kconfig
> b/drivers/hwtracing/coresight/Kconfig
> index ef9cb3c164e1..ea6da47c136a 100644
> --- a/drivers/hwtracing/coresight/Kconfig
> +++ b/drivers/hwtracing/coresight/Kconfig
> @@ -3,6 +3,7 @@
> #
> menuconfig CORESIGHT
> bool "CoreSight Tracing Support"
> + depends on BROKEN
> select ARM_AMBA
> select PERF_EVENTS
> help
> diff --git a/drivers/hwtracing/stm/Kconfig b/drivers/hwtracing/stm/Kconfig
> index 723e2d90083d..0e0080d28ad5 100644
> --- a/drivers/hwtracing/stm/Kconfig
> +++ b/drivers/hwtracing/stm/Kconfig
> @@ -1,5 +1,6 @@
> config STM
> tristate "System Trace Module devices"
> + depends on BROKEN
> select CONFIGFS_FS
> select SRCU
> help
> diff --git a/drivers/infiniband/Kconfig b/drivers/infiniband/Kconfig
> index 5cd700421695..f64fe02a5858 100644
> --- a/drivers/infiniband/Kconfig
> +++ b/drivers/infiniband/Kconfig
> @@ -51,7 +51,7 @@ config INFINIBAND_USER_MEM
>
> config INFINIBAND_ON_DEMAND_PAGING
> bool "InfiniBand on-demand paging support"
> - depends on INFINIBAND_USER_MEM
> + depends on INFINIBAND_USER_MEM && BROKEN
> select MMU_NOTIFIER
> default y
> ---help---
> diff --git a/drivers/infiniband/hw/hfi1/Kconfig
> b/drivers/infiniband/hw/hfi1/Kconfig
> index 7b146b67a80f..b41fd3506be9 100644
> --- a/drivers/infiniband/hw/hfi1/Kconfig
> +++ b/drivers/infiniband/hw/hfi1/Kconfig
> @@ -1,6 +1,6 @@
> config INFINIBAND_HFI1
> tristate "Intel OPA Gen1 support"
> - depends on X86_64 && INFINIBAND_RDMAVT && I2C
> + depends on X86_64 && INFINIBAND_RDMAVT && I2C && BROKEN
> select MMU_NOTIFIER
> select CRC32
> select I2C_ALGOBIT
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index f3a21343e636..48c4d5a321da 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -128,7 +128,7 @@ config AMD_IOMMU
>
> config AMD_IOMMU_V2
> tristate "AMD IOMMU Version 2 driver"
> - depends on AMD_IOMMU
> + depends on AMD_IOMMU && BROKEN
> select MMU_NOTIFIER
> ---help---
> This option enables support for the AMD IOMMUv2 features of the IOMMU
> @@ -154,7 +154,7 @@ config INTEL_IOMMU
>
> config INTEL_IOMMU_SVM
> bool "Support for Shared Virtual Memory with Intel IOMMU"
> - depends on INTEL_IOMMU && X86
> + depends on INTEL_IOMMU && X86 && BROKEN
> select PCI_PASID
> select MMU_NOTIFIER
> help
> diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
> index 2c8ac3688815..8b0ae082872a 100644
> --- a/drivers/md/Kconfig
> +++ b/drivers/md/Kconfig
> @@ -4,7 +4,7 @@
>
> menuconfig MD
> bool "Multiple devices driver support (RAID and LVM)"
> - depends on BLOCK
> + depends on BLOCK && BROKEN
> select SRCU
> help
> Support multiple physical spindles through a single logical device.
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index 7c0fa24f9067..eea5f553860a 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -284,7 +284,7 @@ config QCOM_COINCELL
>
> config SGI_GRU
> tristate "SGI GRU driver"
> - depends on X86_UV && SMP
> + depends on X86_UV && SMP && BROKEN
> default n
> select MMU_NOTIFIER
> ---help---
> diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
> index 944ec3c9282c..bba60a8fd482 100644
> --- a/drivers/net/Kconfig
> +++ b/drivers/net/Kconfig
> @@ -238,6 +238,7 @@ config MACSEC
>
> config NETCONSOLE
> tristate "Network console logging support"
> + depends on BROKEN
> ---help---
> If you want to log kernel messages over the network, enable this.
> See <file:Documentation/networking/netconsole.txt> for details.
> @@ -254,6 +255,7 @@ config NETCONSOLE_DYNAMIC
>
> config NETPOLL
> def_bool NETCONSOLE
> + depends on BROKEN
> select SRCU
>
> config NET_POLL_CONTROLLER
> diff --git a/drivers/opp/Kconfig b/drivers/opp/Kconfig
> index a7fbb93f302c..06894a6fa24c 100644
> --- a/drivers/opp/Kconfig
> +++ b/drivers/opp/Kconfig
> @@ -1,5 +1,6 @@
> config PM_OPP
> bool
> + depends on BROKEN
> select SRCU
> ---help---
> SOCs have a standard set of tuples consisting of frequency and
> diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
> index e5d0c28372ea..9761331e0505 100644
> --- a/drivers/xen/Kconfig
> +++ b/drivers/xen/Kconfig
> @@ -146,7 +146,7 @@ config XEN_XENBUS_FRONTEND
>
> config XEN_GNTDEV
> tristate "userspace grant access device driver"
> - depends on XEN
> + depends on XEN && BROKEN
> default m
> select MMU_NOTIFIER
> help
> diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig
> index 273351ee4c46..66a0d7688630 100644
> --- a/fs/btrfs/Kconfig
> +++ b/fs/btrfs/Kconfig
> @@ -1,5 +1,6 @@
> config BTRFS_FS
> tristate "Btrfs filesystem support"
> + depends on BROKEN
> select CRYPTO
> select CRYPTO_CRC32C
> select ZLIB_INFLATE
> diff --git a/fs/notify/Kconfig b/fs/notify/Kconfig
> index 2a24249b30af..598ceab78b62 100644
> --- a/fs/notify/Kconfig
> +++ b/fs/notify/Kconfig
> @@ -1,5 +1,6 @@
> config FSNOTIFY
> def_bool n
> + depends on BROKEN
> select SRCU
>
> source "fs/notify/dnotify/Kconfig"
> diff --git a/fs/notify/dnotify/Kconfig b/fs/notify/dnotify/Kconfig
> index f9c1ca139d8f..f6964a9a5eb9 100644
> --- a/fs/notify/dnotify/Kconfig
> +++ b/fs/notify/dnotify/Kconfig
> @@ -1,5 +1,6 @@
> config DNOTIFY
> bool "Dnotify support"
> + depends on BROKEN
> select FSNOTIFY
> default y
> help
> diff --git a/fs/notify/fanotify/Kconfig b/fs/notify/fanotify/Kconfig
> index 41355ce74ac0..fcb2edd643d4 100644
> --- a/fs/notify/fanotify/Kconfig
> +++ b/fs/notify/fanotify/Kconfig
> @@ -1,5 +1,6 @@
> config FANOTIFY
> bool "Filesystem wide access notification"
> + depends on BROKEN
> select FSNOTIFY
> select ANON_INODES
> default n
> diff --git a/fs/notify/inotify/Kconfig b/fs/notify/inotify/Kconfig
> index b981fc0c8379..916cbd5569fa 100644
> --- a/fs/notify/inotify/Kconfig
> +++ b/fs/notify/inotify/Kconfig
> @@ -1,5 +1,6 @@
> config INOTIFY_USER
> bool "Inotify support for userspace"
> + depends on BROKEN
> select ANON_INODES
> select FSNOTIFY
> default y
> diff --git a/fs/quota/Kconfig b/fs/quota/Kconfig
> index 4a09975aac90..dbf3f3cdcbd8 100644
> --- a/fs/quota/Kconfig
> +++ b/fs/quota/Kconfig
> @@ -4,6 +4,7 @@
>
> config QUOTA
> bool "Quota support"
> + depends on BROKEN
> select QUOTACTL
> select SRCU
> help
> diff --git a/include/linux/srcu.h b/include/linux/srcu.h
> index 62be8966e837..587128fcec05 100644
> --- a/include/linux/srcu.h
> +++ b/include/linux/srcu.h
> @@ -94,9 +94,11 @@ void synchronize_srcu(struct srcu_struct *sp);
> */
> static inline int srcu_read_lock_held(struct srcu_struct *sp)
> {
> - if (!debug_lockdep_rcu_enabled())
> - return 1;
> +#ifdef CONFIG_SRCU
> return lock_is_held(&sp->dep_map);
> +#else /* #ifdef CONFIG_PROVE_RCU */
> + return 1;
> +#endif /* #else #ifdef CONFIG_PROVE_RCU */
> }
>
> #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
> @@ -157,7 +159,9 @@ static inline int srcu_read_lock(struct
> srcu_struct *sp) __acquires(sp)
> int retval;
>
> retval = __srcu_read_lock(sp);
> +#ifdef CONFIG_SRCU
> rcu_lock_acquire(&(sp)->dep_map);
> +#endif
> return retval;
> }
>
> @@ -171,7 +175,9 @@ static inline int srcu_read_lock(struct
> srcu_struct *sp) __acquires(sp)
> static inline void srcu_read_unlock(struct srcu_struct *sp, int idx)
> __releases(sp)
> {
> +#ifdef CONFIG_SRCU
> rcu_lock_release(&(sp)->dep_map);
> +#endif
> __srcu_read_unlock(sp, idx);
> }
>
> diff --git a/init/Kconfig b/init/Kconfig
> index a9a2e2c86671..b68adf1b1373 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -311,12 +311,12 @@ config AUDITSYSCALL
>
> config AUDIT_WATCH
> def_bool y
> - depends on AUDITSYSCALL
> + depends on AUDITSYSCALL && BROKEN
> select FSNOTIFY
>
> config AUDIT_TREE
> def_bool y
> - depends on AUDITSYSCALL
> + depends on AUDITSYSCALL && BROKEN
> select FSNOTIFY
>
> source "kernel/irq/Kconfig"
> @@ -1443,6 +1443,7 @@ menu "Kernel Performance Events And Counters"
> config PERF_EVENTS
> bool "Kernel performance events and counters"
> default y if PROFILING
> + depends on BROKEN
> depends on HAVE_PERF_EVENTS
> select ANON_INODES
> select IRQ_WORK
> diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
> index 9210379c0353..4df64e8ca66a 100644
> --- a/kernel/rcu/Kconfig
> +++ b/kernel/rcu/Kconfig
> @@ -51,6 +51,7 @@ config RCU_EXPERT
>
> config SRCU
> bool
> + depends on BROKEN
> help
> This option selects the sleepable version of RCU. This version
> permits arbitrary sleeping or blocking within RCU read-side critical
> @@ -70,6 +71,7 @@ config TREE_SRCU
>
> config TASKS_RCU
> def_bool PREEMPT
> + depends on BROKEN
> select SRCU
> help
> This option enables a task-based RCU implementation that uses
> diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug
> index 0ec7d1d33a14..a66eb614ae39 100644
> --- a/kernel/rcu/Kconfig.debug
> +++ b/kernel/rcu/Kconfig.debug
> @@ -13,7 +13,7 @@ config TORTURE_TEST
>
> config RCU_PERF_TEST
> tristate "performance tests for RCU"
> - depends on DEBUG_KERNEL
> + depends on DEBUG_KERNEL && BROKEN
> select TORTURE_TEST
> select SRCU
> select TASKS_RCU
> @@ -30,7 +30,7 @@ config RCU_PERF_TEST
>
> config RCU_TORTURE_TEST
> tristate "torture tests for RCU"
> - depends on DEBUG_KERNEL
> + depends on DEBUG_KERNEL && BROKEN
> select TORTURE_TEST
> select SRCU
> select TASKS_RCU
> diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> index 7114c885a78a..b52390595727 100644
> --- a/kernel/trace/Kconfig
> +++ b/kernel/trace/Kconfig
> @@ -131,6 +131,7 @@ if FTRACE
> config FUNCTION_TRACER
> bool "Kernel Function Tracer"
> depends on HAVE_FUNCTION_TRACER
> + depends on BROKEN || !PREEMPT
> select KALLSYMS
> select GENERIC_TRACER
> select CONTEXT_SWITCH_TRACER
> @@ -395,7 +396,7 @@ config BRANCH_TRACER
>
> config STACK_TRACER
> bool "Trace max stack"
> - depends on HAVE_FUNCTION_TRACER
> + depends on HAVE_FUNCTION_TRACER && BROKEN
> select FUNCTION_TRACER
> select STACKTRACE
> select KALLSYMS
> diff --git a/mm/Kconfig b/mm/Kconfig
> index c782e8fb7235..17c9e82935da 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -300,6 +300,7 @@ config VIRT_TO_BUS
>
> config MMU_NOTIFIER
> bool
> + depends on BROKEN
> select SRCU
>
> config KSM
> @@ -706,7 +707,7 @@ config HMM
>
> config HMM_MIRROR
> bool "HMM mirror CPU page table into a device page table"
> - depends on ARCH_HAS_HMM
> + depends on ARCH_HAS_HMM && BROKEN
> select MMU_NOTIFIER
> select HMM
> help
> diff --git a/security/tomoyo/Kconfig b/security/tomoyo/Kconfig
> index 404dce66952a..3a664764fb19 100644
> --- a/security/tomoyo/Kconfig
> +++ b/security/tomoyo/Kconfig
> @@ -1,5 +1,6 @@
> config SECURITY_TOMOYO
> - bool "TOMOYO Linux Support"
> + bool "TOMOYO Linux Support"
> + depends on BROKEN
> depends on SECURITY
> depends on NET
> select SECURITYFS
>