From: Ingo Molnar <[email protected]>
offer the following lock validation options:
CONFIG_PROVE_SPIN_LOCKING
CONFIG_PROVE_RW_LOCKING
CONFIG_PROVE_MUTEX_LOCKING
CONFIG_PROVE_RWSEM_LOCKING
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Arjan van de Ven <[email protected]>
---
lib/Kconfig.debug | 167 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 167 insertions(+)
Index: linux/lib/Kconfig.debug
===================================================================
--- linux.orig/lib/Kconfig.debug
+++ linux/lib/Kconfig.debug
@@ -184,6 +184,173 @@ config DEBUG_SPINLOCK
best used in conjunction with the NMI watchdog so that spinlock
deadlocks are also debuggable.
+config PROVE_SPIN_LOCKING
+ bool "Prove spin-locking correctness"
+ default y
+ help
+ This feature enables the kernel to prove that all spinlock
+ locking that occurs in the kernel runtime is mathematically
+ correct: that under no circumstance could an arbitrary (and
+ not yet triggered) combination of observed spinlock locking
+ sequences (on an arbitrary number of CPUs, running an
+ arbitrary number of tasks and interrupt contexts) cause a
+ deadlock.
+
+ In short, this feature enables the kernel to report spinlock
+ deadlocks before they actually occur.
+
+ The proof does not depend on how hard and complex a
+ deadlock scenario would be to trigger: how many
+ participant CPUs, tasks and irq-contexts would be needed
+ for it to trigger. The proof also does not depend on
+ timing: if a race and a resulting deadlock is possible
+ theoretically (no matter how unlikely the race scenario
+ is), it will be proven so and will immediately be
+ reported by the kernel (once the event is observed that
+ makes the deadlock theoretically possible).
+
+ If a deadlock is impossible (i.e. the locking rules, as
+ observed by the kernel, are mathematically correct), the
+ kernel reports nothing.
+
+ NOTE: this feature can also be enabled for rwlocks, mutexes
+ and rwsems - in which case all dependencies between these
+ different locking variants are observed and mapped too, and
+ the proof of observed correctness is also maintained for an
+ arbitrary combination of these separate locking variants.
+
+ For more details, see Documentation/locking-correctness.txt.
+
+config PROVE_RW_LOCKING
+ bool "Prove rw-locking correctness"
+ default y
+ help
+ This feature enables the kernel to prove that all rwlock
+ locking that occurs in the kernel runtime is mathematically
+ correct: that under no circumstance could an arbitrary (and
+ not yet triggered) combination of observed rwlock locking
+ sequences (on an arbitrary number of CPUs, running an
+ arbitrary number of tasks and interrupt contexts) cause a
+ deadlock.
+
+ In short, this feature enables the kernel to report rwlock
+ deadlocks before they actually occur.
+
+ The proof does not depend on how hard and complex a
+ deadlock scenario would be to trigger: how many
+ participant CPUs, tasks and irq-contexts would be needed
+ for it to trigger. The proof also does not depend on
+ timing: if a race and a resulting deadlock is possible
+ theoretically (no matter how unlikely the race scenario
+ is), it will be proven so and will immediately be
+ reported by the kernel (once the event is observed that
+ makes the deadlock theoretically possible).
+
+ If a deadlock is impossible (i.e. the locking rules, as
+ observed by the kernel, are mathematically correct), the
+ kernel reports nothing.
+
+ NOTE: this feature can also be enabled for spinlocks, mutexes
+ and rwsems - in which case all dependencies between these
+ different locking variants are observed and mapped too, and
+ the proof of observed correctness is also maintained for an
+ arbitrary combination of these separate locking variants.
+
+ For more details, see Documentation/locking-correctness.txt.
+
+config PROVE_MUTEX_LOCKING
+ bool "Prove mutex-locking correctness"
+ default y
+ help
+ This feature enables the kernel to prove that all mutexlock
+ locking that occurs in the kernel runtime is mathematically
+ correct: that under no circumstance could an arbitrary (and
+ not yet triggered) combination of observed mutexlock locking
+ sequences (on an arbitrary number of CPUs, running an
+ arbitrary number of tasks and interrupt contexts) cause a
+ deadlock.
+
+ In short, this feature enables the kernel to report mutexlock
+ deadlocks before they actually occur.
+
+ The proof does not depend on how hard and complex a
+ deadlock scenario would be to trigger: how many
+ participant CPUs, tasks and irq-contexts would be needed
+ for it to trigger. The proof also does not depend on
+ timing: if a race and a resulting deadlock is possible
+ theoretically (no matter how unlikely the race scenario
+ is), it will be proven so and will immediately be
+ reported by the kernel (once the event is observed that
+ makes the deadlock theoretically possible).
+
+ If a deadlock is impossible (i.e. the locking rules, as
+ observed by the kernel, are mathematically correct), the
+ kernel reports nothing.
+
+ NOTE: this feature can also be enabled for spinlock, rwlocks
+ and rwsems - in which case all dependencies between these
+ different locking variants are observed and mapped too, and
+ the proof of observed correctness is also maintained for an
+ arbitrary combination of these separate locking variants.
+
+ For more details, see Documentation/locking-correctness.txt.
+
+config PROVE_RWSEM_LOCKING
+ bool "Prove rwsem-locking correctness"
+ default y
+ help
+ This feature enables the kernel to prove that all rwsemlock
+ locking that occurs in the kernel runtime is mathematically
+ correct: that under no circumstance could an arbitrary (and
+ not yet triggered) combination of observed rwsemlock locking
+ sequences (on an arbitrary number of CPUs, running an
+ arbitrary number of tasks and interrupt contexts) cause a
+ deadlock.
+
+ In short, this feature enables the kernel to report rwsemlock
+ deadlocks before they actually occur.
+
+ The proof does not depend on how hard and complex a
+ deadlock scenario would be to trigger: how many
+ participant CPUs, tasks and irq-contexts would be needed
+ for it to trigger. The proof also does not depend on
+ timing: if a race and a resulting deadlock is possible
+ theoretically (no matter how unlikely the race scenario
+ is), it will be proven so and will immediately be
+ reported by the kernel (once the event is observed that
+ makes the deadlock theoretically possible).
+
+ If a deadlock is impossible (i.e. the locking rules, as
+ observed by the kernel, are mathematically correct), the
+ kernel reports nothing.
+
+ NOTE: this feature can also be enabled for spinlocks, rwlocks
+ and mutexes - in which case all dependencies between these
+ different locking variants are observed and mapped too, and
+ the proof of observed correctness is also maintained for an
+ arbitrary combination of these separate locking variants.
+
+ For more details, see Documentation/locking-correctness.txt.
+
+config LOCKDEP
+ bool
+ default y
+ depends on PROVE_SPIN_LOCKING || PROVE_RW_LOCKING || PROVE_MUTEX_LOCKING || PROVE_RWSEM_LOCKING
+
+config DEBUG_LOCKDEP
+ bool "Lock dependency engine debugging"
+ depends on LOCKDEP
+ default y
+ help
+ If you say Y here, the lock dependency engine will do
+ additional runtime checks to debug itself, at the price
+ of more runtime overhead.
+
+config TRACE_IRQFLAGS
+ bool
+ default y
+ depends on PROVE_SPIN_LOCKING || PROVE_RW_LOCKING
+
config DEBUG_SPINLOCK_SLEEP
bool "Sleep-inside-spinlock checking"
depends on DEBUG_KERNEL
-
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