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rcu: Add lockdep_assert_in_rcu_read_lock() and friends

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There is no direct RCU counterpart to lockdep_assert_irqs_disabled()
and friends.  Although it is possible to construct them, it would
be more convenient to have the following lockdep assertions:

lockdep_assert_in_rcu_read_lock()
lockdep_assert_in_rcu_read_lock_bh()
lockdep_assert_in_rcu_read_lock_sched()
lockdep_assert_in_rcu_reader()

This commit therefore creates them.

Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Paul E. McKenney 2024-03-16 00:10:15 -07:00
parent 1613e604df
commit 32d99593bd
1 changed files with 60 additions and 0 deletions
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60
include/linux/rcupdate.h
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@ -421,11 +421,71 @@ static inline void rcu_preempt_sleep_check(void) { }
"Illegal context switch in RCU-sched read-side critical section"); \
} while (0)
// See RCU_LOCKDEP_WARN() for an explanation of the double call to
// debug_lockdep_rcu_enabled().
static inline bool lockdep_assert_rcu_helper(bool c)
{
return debug_lockdep_rcu_enabled() &&
(c || !rcu_is_watching() || !rcu_lockdep_current_cpu_online()) &&
debug_lockdep_rcu_enabled();
}
/**
* lockdep_assert_in_rcu_read_lock - WARN if not protected by rcu_read_lock()
*
* Splats if lockdep is enabled and there is no rcu_read_lock() in effect.
*/
#define lockdep_assert_in_rcu_read_lock() \
WARN_ON_ONCE(lockdep_assert_rcu_helper(!lock_is_held(&rcu_lock_map)))
/**
* lockdep_assert_in_rcu_read_lock_bh - WARN if not protected by rcu_read_lock_bh()
*
* Splats if lockdep is enabled and there is no rcu_read_lock_bh() in effect.
* Note that local_bh_disable() and friends do not suffice here, instead an
* actual rcu_read_lock_bh() is required.
*/
#define lockdep_assert_in_rcu_read_lock_bh() \
WARN_ON_ONCE(lockdep_assert_rcu_helper(!lock_is_held(&rcu_bh_lock_map)))
/**
* lockdep_assert_in_rcu_read_lock_sched - WARN if not protected by rcu_read_lock_sched()
*
* Splats if lockdep is enabled and there is no rcu_read_lock_sched()
* in effect. Note that preempt_disable() and friends do not suffice here,
* instead an actual rcu_read_lock_sched() is required.
*/
#define lockdep_assert_in_rcu_read_lock_sched() \
WARN_ON_ONCE(lockdep_assert_rcu_helper(!lock_is_held(&rcu_sched_lock_map)))
/**
* lockdep_assert_in_rcu_reader - WARN if not within some type of RCU reader
*
* Splats if lockdep is enabled and there is no RCU reader of any
* type in effect. Note that regions of code protected by things like
* preempt_disable, local_bh_disable(), and local_irq_disable() all qualify
* as RCU readers.
*
* Note that this will never trigger in PREEMPT_NONE or PREEMPT_VOLUNTARY
* kernels that are not also built with PREEMPT_COUNT. But if you have
* lockdep enabled, you might as well also enable PREEMPT_COUNT.
*/
#define lockdep_assert_in_rcu_reader() \
WARN_ON_ONCE(lockdep_assert_rcu_helper(!lock_is_held(&rcu_lock_map) && \
!lock_is_held(&rcu_bh_lock_map) && \
!lock_is_held(&rcu_sched_lock_map) && \
preemptible()))
#else /* #ifdef CONFIG_PROVE_RCU */
#define RCU_LOCKDEP_WARN(c, s) do { } while (0 && (c))
#define rcu_sleep_check() do { } while (0)
#define lockdep_assert_in_rcu_read_lock() do { } while (0)
#define lockdep_assert_in_rcu_read_lock_bh() do { } while (0)
#define lockdep_assert_in_rcu_read_lock_sched() do { } while (0)
#define lockdep_assert_in_rcu_reader() do { } while (0)
#endif /* #else #ifdef CONFIG_PROVE_RCU */
/*