This demonstrates a larger conversion to use Clang's context analysis. The benefit is additional static checking of locking rules, along with better documentation.
Notably, kernel/sched contains sufficiently complex synchronization patterns, and application to core.c & fair.c demonstrates that the latest Clang version has become powerful enough to start applying this to more complex subsystems (with some modest annotations and changes). Signed-off-by: Marco Elver <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Ingo Molnar <[email protected]> --- v5: * Rename "context guard" -> "context lock". * Use new cleanup.h helpers to properly support scoped lock guards. v4: * Rename capability -> context analysis. v3: * New patch. --- include/linux/sched.h | 6 +- include/linux/sched/signal.h | 4 +- include/linux/sched/task.h | 6 +- include/linux/sched/wake_q.h | 3 + kernel/sched/Makefile | 3 + kernel/sched/core.c | 89 +++++++++++----- kernel/sched/fair.c | 7 +- kernel/sched/sched.h | 126 ++++++++++++++++------- scripts/context-analysis-suppression.txt | 1 + 9 files changed, 177 insertions(+), 68 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index d395f2810fac..c4022647282e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2094,9 +2094,9 @@ static inline int _cond_resched(void) _cond_resched(); \ }) -extern int __cond_resched_lock(spinlock_t *lock); -extern int __cond_resched_rwlock_read(rwlock_t *lock); -extern int __cond_resched_rwlock_write(rwlock_t *lock); +extern int __cond_resched_lock(spinlock_t *lock) __must_hold(lock); +extern int __cond_resched_rwlock_read(rwlock_t *lock) __must_hold_shared(lock); +extern int __cond_resched_rwlock_write(rwlock_t *lock) __must_hold(lock); #define MIGHT_RESCHED_RCU_SHIFT 8 #define MIGHT_RESCHED_PREEMPT_MASK ((1U << MIGHT_RESCHED_RCU_SHIFT) - 1) diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h index a63f65aa5bdd..a22248aebcf9 100644 --- a/include/linux/sched/signal.h +++ b/include/linux/sched/signal.h @@ -738,10 +738,12 @@ static inline int thread_group_empty(struct task_struct *p) (thread_group_leader(p) && !thread_group_empty(p)) extern struct sighand_struct *lock_task_sighand(struct task_struct *task, - unsigned long *flags); + unsigned long *flags) + __acquires(&task->sighand->siglock); static inline void unlock_task_sighand(struct task_struct *task, unsigned long *flags) + __releases(&task->sighand->siglock) { spin_unlock_irqrestore(&task->sighand->siglock, *flags); } diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h index 525aa2a632b2..41ed884cffc9 100644 --- a/include/linux/sched/task.h +++ b/include/linux/sched/task.h @@ -214,15 +214,19 @@ static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) * write_lock_irq(&tasklist_lock), neither inside nor outside. */ static inline void task_lock(struct task_struct *p) + __acquires(&p->alloc_lock) { spin_lock(&p->alloc_lock); } static inline void task_unlock(struct task_struct *p) + __releases(&p->alloc_lock) { spin_unlock(&p->alloc_lock); } -DEFINE_GUARD(task_lock, struct task_struct *, task_lock(_T), task_unlock(_T)) +DEFINE_LOCK_GUARD_1(task_lock, struct task_struct, task_lock(_T->lock), task_unlock(_T->lock)) +DECLARE_LOCK_GUARD_1_ATTRS(task_lock, __acquires(&_T->alloc_lock), __releases(&(*(struct task_struct **)_T)->alloc_lock)) +#define class_task_lock_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(task_lock, _T) #endif /* _LINUX_SCHED_TASK_H */ diff --git a/include/linux/sched/wake_q.h b/include/linux/sched/wake_q.h index 0f28b4623ad4..765bbc3d54be 100644 --- a/include/linux/sched/wake_q.h +++ b/include/linux/sched/wake_q.h @@ -66,6 +66,7 @@ extern void wake_up_q(struct wake_q_head *head); /* Spin unlock helpers to unlock and call wake_up_q with preempt disabled */ static inline void raw_spin_unlock_wake(raw_spinlock_t *lock, struct wake_q_head *wake_q) + __releases(lock) { guard(preempt)(); raw_spin_unlock(lock); @@ -77,6 +78,7 @@ void raw_spin_unlock_wake(raw_spinlock_t *lock, struct wake_q_head *wake_q) static inline void raw_spin_unlock_irq_wake(raw_spinlock_t *lock, struct wake_q_head *wake_q) + __releases(lock) { guard(preempt)(); raw_spin_unlock_irq(lock); @@ -89,6 +91,7 @@ void raw_spin_unlock_irq_wake(raw_spinlock_t *lock, struct wake_q_head *wake_q) static inline void raw_spin_unlock_irqrestore_wake(raw_spinlock_t *lock, unsigned long flags, struct wake_q_head *wake_q) + __releases(lock) { guard(preempt)(); raw_spin_unlock_irqrestore(lock, flags); diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile index 8ae86371ddcd..b1f1a367034f 100644 --- a/kernel/sched/Makefile +++ b/kernel/sched/Makefile @@ -1,5 +1,8 @@ # SPDX-License-Identifier: GPL-2.0 +CONTEXT_ANALYSIS_core.o := y +CONTEXT_ANALYSIS_fair.o := y + # The compilers are complaining about unused variables inside an if(0) scope # block. This is daft, shut them up. ccflags-y += $(call cc-disable-warning, unused-but-set-variable) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 41ba0be16911..ae543ee91272 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -396,6 +396,8 @@ static atomic_t sched_core_count; static struct cpumask sched_core_mask; static void sched_core_lock(int cpu, unsigned long *flags) + __context_unsafe(/* acquires multiple */) + __acquires(&runqueues.__lock) /* overapproximation */ { const struct cpumask *smt_mask = cpu_smt_mask(cpu); int t, i = 0; @@ -406,6 +408,8 @@ static void sched_core_lock(int cpu, unsigned long *flags) } static void sched_core_unlock(int cpu, unsigned long *flags) + __context_unsafe(/* releases multiple */) + __releases(&runqueues.__lock) /* overapproximation */ { const struct cpumask *smt_mask = cpu_smt_mask(cpu); int t; @@ -630,6 +634,7 @@ EXPORT_SYMBOL(__trace_set_current_state); */ void raw_spin_rq_lock_nested(struct rq *rq, int subclass) + __context_unsafe() { raw_spinlock_t *lock; @@ -655,6 +660,7 @@ void raw_spin_rq_lock_nested(struct rq *rq, int subclass) } bool raw_spin_rq_trylock(struct rq *rq) + __context_unsafe() { raw_spinlock_t *lock; bool ret; @@ -696,15 +702,16 @@ void double_rq_lock(struct rq *rq1, struct rq *rq2) raw_spin_rq_lock(rq1); if (__rq_lockp(rq1) != __rq_lockp(rq2)) raw_spin_rq_lock_nested(rq2, SINGLE_DEPTH_NESTING); + else + __acquire_ctx_lock(__rq_lockp(rq2)); /* fake acquire */ double_rq_clock_clear_update(rq1, rq2); } /* - * __task_rq_lock - lock the rq @p resides on. + * ___task_rq_lock - lock the rq @p resides on. */ -struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf) - __acquires(rq->lock) +struct rq *___task_rq_lock(struct task_struct *p, struct rq_flags *rf) { struct rq *rq; @@ -727,9 +734,7 @@ struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf) /* * task_rq_lock - lock p->pi_lock and lock the rq @p resides on. */ -struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf) - __acquires(p->pi_lock) - __acquires(rq->lock) +struct rq *_task_rq_lock(struct task_struct *p, struct rq_flags *rf) { struct rq *rq; @@ -2431,6 +2436,7 @@ static inline bool is_cpu_allowed(struct task_struct *p, int cpu) */ static struct rq *move_queued_task(struct rq *rq, struct rq_flags *rf, struct task_struct *p, int new_cpu) + __must_hold(__rq_lockp(rq)) { lockdep_assert_rq_held(rq); @@ -2477,6 +2483,7 @@ struct set_affinity_pending { */ static struct rq *__migrate_task(struct rq *rq, struct rq_flags *rf, struct task_struct *p, int dest_cpu) + __must_hold(__rq_lockp(rq)) { /* Affinity changed (again). */ if (!is_cpu_allowed(p, dest_cpu)) @@ -2513,6 +2520,12 @@ static int migration_cpu_stop(void *data) */ flush_smp_call_function_queue(); + /* + * We may change the underlying rq, but the locks held will + * appropriately be "transferred" when switching. + */ + context_unsafe_alias(rq); + raw_spin_lock(&p->pi_lock); rq_lock(rq, &rf); @@ -2624,6 +2637,8 @@ int push_cpu_stop(void *arg) if (!lowest_rq) goto out_unlock; + lockdep_assert_rq_held(lowest_rq); + // XXX validate p is still the highest prio task if (task_rq(p) == rq) { move_queued_task_locked(rq, lowest_rq, p); @@ -2834,8 +2849,7 @@ void release_user_cpus_ptr(struct task_struct *p) */ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flags *rf, int dest_cpu, unsigned int flags) - __releases(rq->lock) - __releases(p->pi_lock) + __releases(__rq_lockp(rq), &p->pi_lock) { struct set_affinity_pending my_pending = { }, *pending = NULL; bool stop_pending, complete = false; @@ -2990,8 +3004,7 @@ static int __set_cpus_allowed_ptr_locked(struct task_struct *p, struct affinity_context *ctx, struct rq *rq, struct rq_flags *rf) - __releases(rq->lock) - __releases(p->pi_lock) + __releases(__rq_lockp(rq), &p->pi_lock) { const struct cpumask *cpu_allowed_mask = task_cpu_possible_mask(p); const struct cpumask *cpu_valid_mask = cpu_active_mask; @@ -4273,29 +4286,30 @@ static bool __task_needs_rq_lock(struct task_struct *p) */ int task_call_func(struct task_struct *p, task_call_f func, void *arg) { - struct rq *rq = NULL; struct rq_flags rf; int ret; raw_spin_lock_irqsave(&p->pi_lock, rf.flags); - if (__task_needs_rq_lock(p)) - rq = __task_rq_lock(p, &rf); + if (__task_needs_rq_lock(p)) { + struct rq *rq = __task_rq_lock(p, &rf); - /* - * At this point the task is pinned; either: - * - blocked and we're holding off wakeups (pi->lock) - * - woken, and we're holding off enqueue (rq->lock) - * - queued, and we're holding off schedule (rq->lock) - * - running, and we're holding off de-schedule (rq->lock) - * - * The called function (@func) can use: task_curr(), p->on_rq and - * p->__state to differentiate between these states. - */ - ret = func(p, arg); + /* + * At this point the task is pinned; either: + * - blocked and we're holding off wakeups (pi->lock) + * - woken, and we're holding off enqueue (rq->lock) + * - queued, and we're holding off schedule (rq->lock) + * - running, and we're holding off de-schedule (rq->lock) + * + * The called function (@func) can use: task_curr(), p->on_rq and + * p->__state to differentiate between these states. + */ + ret = func(p, arg); - if (rq) __task_rq_unlock(rq, p, &rf); + } else { + ret = func(p, arg); + } raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags); return ret; @@ -4968,6 +4982,8 @@ void balance_callbacks(struct rq *rq, struct balance_callback *head) static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next, struct rq_flags *rf) + __releases(__rq_lockp(rq)) + __acquires(__rq_lockp(this_rq())) { /* * Since the runqueue lock will be released by the next @@ -4981,9 +4997,15 @@ prepare_lock_switch(struct rq *rq, struct task_struct *next, struct rq_flags *rf /* this is a valid case when another task releases the spinlock */ rq_lockp(rq)->owner = next; #endif + /* + * Model the rq reference switcheroo. + */ + __release(__rq_lockp(rq)); + __acquire(__rq_lockp(this_rq())); } static inline void finish_lock_switch(struct rq *rq) + __releases(__rq_lockp(rq)) { /* * If we are tracking spinlock dependencies then we have to @@ -5039,6 +5061,7 @@ static inline void kmap_local_sched_in(void) static inline void prepare_task_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next) + __must_hold(__rq_lockp(rq)) { kcov_prepare_switch(prev); sched_info_switch(rq, prev, next); @@ -5069,7 +5092,7 @@ prepare_task_switch(struct rq *rq, struct task_struct *prev, * because prev may have moved to another CPU. */ static struct rq *finish_task_switch(struct task_struct *prev) - __releases(rq->lock) + __releases(__rq_lockp(this_rq())) { struct rq *rq = this_rq(); struct mm_struct *mm = rq->prev_mm; @@ -5165,7 +5188,7 @@ static struct rq *finish_task_switch(struct task_struct *prev) * @prev: the thread we just switched away from. */ asmlinkage __visible void schedule_tail(struct task_struct *prev) - __releases(rq->lock) + __releases(__rq_lockp(this_rq())) { /* * New tasks start with FORK_PREEMPT_COUNT, see there and @@ -5197,6 +5220,7 @@ asmlinkage __visible void schedule_tail(struct task_struct *prev) static __always_inline struct rq * context_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next, struct rq_flags *rf) + __releases(__rq_lockp(rq)) { prepare_task_switch(rq, prev, next); @@ -5865,6 +5889,7 @@ static void prev_balance(struct rq *rq, struct task_struct *prev, */ static inline struct task_struct * __pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) + __must_hold(__rq_lockp(rq)) { const struct sched_class *class; struct task_struct *p; @@ -5965,6 +5990,7 @@ static void queue_core_balance(struct rq *rq); static struct task_struct * pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) + __must_hold(__rq_lockp(rq)) { struct task_struct *next, *p, *max; const struct cpumask *smt_mask; @@ -6273,6 +6299,7 @@ static bool steal_cookie_task(int cpu, struct sched_domain *sd) } static void sched_core_balance(struct rq *rq) + __must_hold(__rq_lockp(rq)) { struct sched_domain *sd; int cpu = cpu_of(rq); @@ -6418,6 +6445,7 @@ static inline void sched_core_cpu_dying(unsigned int cpu) {} static struct task_struct * pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) + __must_hold(__rq_lockp(rq)) { return __pick_next_task(rq, prev, rf); } @@ -8043,6 +8071,12 @@ static int __balance_push_cpu_stop(void *arg) int cpu; scoped_guard (raw_spinlock_irq, &p->pi_lock) { + /* + * We may change the underlying rq, but the locks held will + * appropriately be "transferred" when switching. + */ + context_unsafe_alias(rq); + cpu = select_fallback_rq(rq->cpu, p); rq_lock(rq, &rf); @@ -8066,6 +8100,7 @@ static DEFINE_PER_CPU(struct cpu_stop_work, push_work); * effective when the hotplug motion is down. */ static void balance_push(struct rq *rq) + __must_hold(__rq_lockp(rq)) { struct task_struct *push_task = rq->curr; diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index da46c3164537..d0c929ecdb6a 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2860,6 +2860,7 @@ static int preferred_group_nid(struct task_struct *p, int nid) } static void task_numa_placement(struct task_struct *p) + __context_unsafe(/* conditional locking */) { int seq, nid, max_nid = NUMA_NO_NODE; unsigned long max_faults = 0; @@ -4781,7 +4782,8 @@ static inline unsigned long cfs_rq_load_avg(struct cfs_rq *cfs_rq) return cfs_rq->avg.load_avg; } -static int sched_balance_newidle(struct rq *this_rq, struct rq_flags *rf); +static int sched_balance_newidle(struct rq *this_rq, struct rq_flags *rf) + __must_hold(__rq_lockp(this_rq)); static inline unsigned long task_util(struct task_struct *p) { @@ -6188,6 +6190,7 @@ static bool distribute_cfs_runtime(struct cfs_bandwidth *cfs_b) * used to track this state. */ static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun, unsigned long flags) + __must_hold(&cfs_b->lock) { int throttled; @@ -8919,6 +8922,7 @@ static void set_next_task_fair(struct rq *rq, struct task_struct *p, bool first) struct task_struct * pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) + __must_hold(__rq_lockp(rq)) { struct sched_entity *se; struct task_struct *p; @@ -12858,6 +12862,7 @@ static inline void nohz_newidle_balance(struct rq *this_rq) { } * > 0 - success, new (fair) tasks present */ static int sched_balance_newidle(struct rq *this_rq, struct rq_flags *rf) + __must_hold(__rq_lockp(this_rq)) { unsigned long next_balance = jiffies + HZ; int this_cpu = this_rq->cpu; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index d30cca6870f5..25d2ff265227 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1358,8 +1358,13 @@ static inline u32 sched_rng(void) return prandom_u32_state(this_cpu_ptr(&sched_rnd_state)); } +static __always_inline struct rq *__this_rq(void) +{ + return this_cpu_ptr(&runqueues); +} + #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) -#define this_rq() this_cpu_ptr(&runqueues) +#define this_rq() __this_rq() #define task_rq(p) cpu_rq(task_cpu(p)) #define cpu_curr(cpu) (cpu_rq(cpu)->curr) #define raw_rq() raw_cpu_ptr(&runqueues) @@ -1404,6 +1409,7 @@ static inline raw_spinlock_t *rq_lockp(struct rq *rq) } static inline raw_spinlock_t *__rq_lockp(struct rq *rq) + __returns_ctx_lock(rq_lockp(rq)) /* alias them */ { if (rq->core_enabled) return &rq->core->__lock; @@ -1503,6 +1509,7 @@ static inline raw_spinlock_t *rq_lockp(struct rq *rq) } static inline raw_spinlock_t *__rq_lockp(struct rq *rq) + __returns_ctx_lock(rq_lockp(rq)) /* alias them */ { return &rq->__lock; } @@ -1545,32 +1552,42 @@ static inline bool rt_group_sched_enabled(void) #endif /* !CONFIG_RT_GROUP_SCHED */ static inline void lockdep_assert_rq_held(struct rq *rq) + __assumes_ctx_lock(__rq_lockp(rq)) { lockdep_assert_held(__rq_lockp(rq)); } -extern void raw_spin_rq_lock_nested(struct rq *rq, int subclass); -extern bool raw_spin_rq_trylock(struct rq *rq); -extern void raw_spin_rq_unlock(struct rq *rq); +extern void raw_spin_rq_lock_nested(struct rq *rq, int subclass) + __acquires(__rq_lockp(rq)); + +extern bool raw_spin_rq_trylock(struct rq *rq) + __cond_acquires(true, __rq_lockp(rq)); + +extern void raw_spin_rq_unlock(struct rq *rq) + __releases(__rq_lockp(rq)); static inline void raw_spin_rq_lock(struct rq *rq) + __acquires(__rq_lockp(rq)) { raw_spin_rq_lock_nested(rq, 0); } static inline void raw_spin_rq_lock_irq(struct rq *rq) + __acquires(__rq_lockp(rq)) { local_irq_disable(); raw_spin_rq_lock(rq); } static inline void raw_spin_rq_unlock_irq(struct rq *rq) + __releases(__rq_lockp(rq)) { raw_spin_rq_unlock(rq); local_irq_enable(); } static inline unsigned long _raw_spin_rq_lock_irqsave(struct rq *rq) + __acquires(__rq_lockp(rq)) { unsigned long flags; @@ -1581,6 +1598,7 @@ static inline unsigned long _raw_spin_rq_lock_irqsave(struct rq *rq) } static inline void raw_spin_rq_unlock_irqrestore(struct rq *rq, unsigned long flags) + __releases(__rq_lockp(rq)) { raw_spin_rq_unlock(rq); local_irq_restore(flags); @@ -1829,18 +1847,16 @@ static inline void rq_repin_lock(struct rq *rq, struct rq_flags *rf) rq->clock_update_flags |= rf->clock_update_flags; } -extern -struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf) - __acquires(rq->lock); +#define __task_rq_lock(...) __acquire_ret(___task_rq_lock(__VA_ARGS__), __rq_lockp(__ret)) +extern struct rq *___task_rq_lock(struct task_struct *p, struct rq_flags *rf) __acquires_ret; -extern -struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf) - __acquires(p->pi_lock) - __acquires(rq->lock); +#define task_rq_lock(...) __acquire_ret(_task_rq_lock(__VA_ARGS__), __rq_lockp(__ret)) +extern struct rq *_task_rq_lock(struct task_struct *p, struct rq_flags *rf) + __acquires(&p->pi_lock) __acquires_ret; static inline void __task_rq_unlock(struct rq *rq, struct task_struct *p, struct rq_flags *rf) - __releases(rq->lock) + __releases(__rq_lockp(rq)) { rq_unpin_lock(rq, rf); raw_spin_rq_unlock(rq); @@ -1848,8 +1864,7 @@ __task_rq_unlock(struct rq *rq, struct task_struct *p, struct rq_flags *rf) static inline void task_rq_unlock(struct rq *rq, struct task_struct *p, struct rq_flags *rf) - __releases(rq->lock) - __releases(p->pi_lock) + __releases(__rq_lockp(rq), &p->pi_lock) { __task_rq_unlock(rq, p, rf); raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags); @@ -1859,6 +1874,8 @@ DEFINE_LOCK_GUARD_1(task_rq_lock, struct task_struct, _T->rq = task_rq_lock(_T->lock, &_T->rf), task_rq_unlock(_T->rq, _T->lock, &_T->rf), struct rq *rq; struct rq_flags rf) +DECLARE_LOCK_GUARD_1_ATTRS(task_rq_lock, __acquires(_T->pi_lock), __releases((*(struct task_struct **)_T)->pi_lock)) +#define class_task_rq_lock_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(task_rq_lock, _T) DEFINE_LOCK_GUARD_1(__task_rq_lock, struct task_struct, _T->rq = __task_rq_lock(_T->lock, &_T->rf), @@ -1866,42 +1883,42 @@ DEFINE_LOCK_GUARD_1(__task_rq_lock, struct task_struct, struct rq *rq; struct rq_flags rf) static inline void rq_lock_irqsave(struct rq *rq, struct rq_flags *rf) - __acquires(rq->lock) + __acquires(__rq_lockp(rq)) { raw_spin_rq_lock_irqsave(rq, rf->flags); rq_pin_lock(rq, rf); } static inline void rq_lock_irq(struct rq *rq, struct rq_flags *rf) - __acquires(rq->lock) + __acquires(__rq_lockp(rq)) { raw_spin_rq_lock_irq(rq); rq_pin_lock(rq, rf); } static inline void rq_lock(struct rq *rq, struct rq_flags *rf) - __acquires(rq->lock) + __acquires(__rq_lockp(rq)) { raw_spin_rq_lock(rq); rq_pin_lock(rq, rf); } static inline void rq_unlock_irqrestore(struct rq *rq, struct rq_flags *rf) - __releases(rq->lock) + __releases(__rq_lockp(rq)) { rq_unpin_lock(rq, rf); raw_spin_rq_unlock_irqrestore(rq, rf->flags); } static inline void rq_unlock_irq(struct rq *rq, struct rq_flags *rf) - __releases(rq->lock) + __releases(__rq_lockp(rq)) { rq_unpin_lock(rq, rf); raw_spin_rq_unlock_irq(rq); } static inline void rq_unlock(struct rq *rq, struct rq_flags *rf) - __releases(rq->lock) + __releases(__rq_lockp(rq)) { rq_unpin_lock(rq, rf); raw_spin_rq_unlock(rq); @@ -1912,18 +1929,27 @@ DEFINE_LOCK_GUARD_1(rq_lock, struct rq, rq_unlock(_T->lock, &_T->rf), struct rq_flags rf) +DECLARE_LOCK_GUARD_1_ATTRS(rq_lock, __acquires(__rq_lockp(_T)), __releases(__rq_lockp(*(struct rq **)_T))); +#define class_rq_lock_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rq_lock, _T) + DEFINE_LOCK_GUARD_1(rq_lock_irq, struct rq, rq_lock_irq(_T->lock, &_T->rf), rq_unlock_irq(_T->lock, &_T->rf), struct rq_flags rf) +DECLARE_LOCK_GUARD_1_ATTRS(rq_lock_irq, __acquires(__rq_lockp(_T)), __releases(__rq_lockp(*(struct rq **)_T))); +#define class_rq_lock_irq_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rq_lock_irq, _T) + DEFINE_LOCK_GUARD_1(rq_lock_irqsave, struct rq, rq_lock_irqsave(_T->lock, &_T->rf), rq_unlock_irqrestore(_T->lock, &_T->rf), struct rq_flags rf) -static inline struct rq *this_rq_lock_irq(struct rq_flags *rf) - __acquires(rq->lock) +DECLARE_LOCK_GUARD_1_ATTRS(rq_lock_irqsave, __acquires(__rq_lockp(_T)), __releases(__rq_lockp(*(struct rq **)_T))); +#define class_rq_lock_irqsave_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rq_lock_irqsave, _T) + +#define this_rq_lock_irq(...) __acquire_ret(_this_rq_lock_irq(__VA_ARGS__), __rq_lockp(__ret)) +static inline struct rq *_this_rq_lock_irq(struct rq_flags *rf) __acquires_ret { struct rq *rq; @@ -3050,8 +3076,20 @@ static inline void double_rq_clock_clear_update(struct rq *rq1, struct rq *rq2) #define DEFINE_LOCK_GUARD_2(name, type, _lock, _unlock, ...) \ __DEFINE_UNLOCK_GUARD(name, type, _unlock, type *lock2; __VA_ARGS__) \ static inline class_##name##_t class_##name##_constructor(type *lock, type *lock2) \ + __no_context_analysis \ { class_##name##_t _t = { .lock = lock, .lock2 = lock2 }, *_T = &_t; \ _lock; return _t; } +#define DECLARE_LOCK_GUARD_2_ATTRS(_name, _lock, _unlock1, _unlock2) \ +static inline class_##_name##_t class_##_name##_constructor(lock_##_name##_t *_T1, \ + lock_##_name##_t *_T2) _lock; \ +static __always_inline void __class_##_name##_cleanup_ctx1(class_##_name##_t **_T1) \ + __no_context_analysis _unlock1 { } \ +static __always_inline void __class_##_name##_cleanup_ctx2(class_##_name##_t **_T2) \ + __no_context_analysis _unlock2 { } +#define WITH_LOCK_GUARD_2_ATTRS(_name, _T1, _T2) \ + class_##_name##_constructor(_T1, _T2), \ + *__UNIQUE_ID(unlock1) __cleanup(__class_##_name##_cleanup_ctx1) = (void *)(_T1),\ + *__UNIQUE_ID(unlock2) __cleanup(__class_##_name##_cleanup_ctx2) = (void *)(_T2) static inline bool rq_order_less(struct rq *rq1, struct rq *rq2) { @@ -3079,7 +3117,8 @@ static inline bool rq_order_less(struct rq *rq1, struct rq *rq2) return rq1->cpu < rq2->cpu; } -extern void double_rq_lock(struct rq *rq1, struct rq *rq2); +extern void double_rq_lock(struct rq *rq1, struct rq *rq2) + __acquires(__rq_lockp(rq1), __rq_lockp(rq2)); #ifdef CONFIG_PREEMPTION @@ -3092,9 +3131,8 @@ extern void double_rq_lock(struct rq *rq1, struct rq *rq2); * also adds more overhead and therefore may reduce throughput. */ static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest) - __releases(this_rq->lock) - __acquires(busiest->lock) - __acquires(this_rq->lock) + __must_hold(__rq_lockp(this_rq)) + __acquires(__rq_lockp(busiest)) { raw_spin_rq_unlock(this_rq); double_rq_lock(this_rq, busiest); @@ -3111,12 +3149,16 @@ static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest) * regardless of entry order into the function. */ static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest) - __releases(this_rq->lock) - __acquires(busiest->lock) - __acquires(this_rq->lock) + __must_hold(__rq_lockp(this_rq)) + __acquires(__rq_lockp(busiest)) { - if (__rq_lockp(this_rq) == __rq_lockp(busiest) || - likely(raw_spin_rq_trylock(busiest))) { + if (__rq_lockp(this_rq) == __rq_lockp(busiest)) { + __acquire(__rq_lockp(busiest)); /* already held */ + double_rq_clock_clear_update(this_rq, busiest); + return 0; + } + + if (likely(raw_spin_rq_trylock(busiest))) { double_rq_clock_clear_update(this_rq, busiest); return 0; } @@ -3139,6 +3181,8 @@ static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest) * double_lock_balance - lock the busiest runqueue, this_rq is locked already. */ static inline int double_lock_balance(struct rq *this_rq, struct rq *busiest) + __must_hold(__rq_lockp(this_rq)) + __acquires(__rq_lockp(busiest)) { lockdep_assert_irqs_disabled(); @@ -3146,14 +3190,17 @@ static inline int double_lock_balance(struct rq *this_rq, struct rq *busiest) } static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest) - __releases(busiest->lock) + __releases(__rq_lockp(busiest)) { if (__rq_lockp(this_rq) != __rq_lockp(busiest)) raw_spin_rq_unlock(busiest); + else + __release(__rq_lockp(busiest)); /* fake release */ lock_set_subclass(&__rq_lockp(this_rq)->dep_map, 0, _RET_IP_); } static inline void double_lock(spinlock_t *l1, spinlock_t *l2) + __acquires(l1, l2) { if (l1 > l2) swap(l1, l2); @@ -3163,6 +3210,7 @@ static inline void double_lock(spinlock_t *l1, spinlock_t *l2) } static inline void double_lock_irq(spinlock_t *l1, spinlock_t *l2) + __acquires(l1, l2) { if (l1 > l2) swap(l1, l2); @@ -3172,6 +3220,7 @@ static inline void double_lock_irq(spinlock_t *l1, spinlock_t *l2) } static inline void double_raw_lock(raw_spinlock_t *l1, raw_spinlock_t *l2) + __acquires(l1, l2) { if (l1 > l2) swap(l1, l2); @@ -3181,6 +3230,7 @@ static inline void double_raw_lock(raw_spinlock_t *l1, raw_spinlock_t *l2) } static inline void double_raw_unlock(raw_spinlock_t *l1, raw_spinlock_t *l2) + __releases(l1, l2) { raw_spin_unlock(l1); raw_spin_unlock(l2); @@ -3190,6 +3240,13 @@ DEFINE_LOCK_GUARD_2(double_raw_spinlock, raw_spinlock_t, double_raw_lock(_T->lock, _T->lock2), double_raw_unlock(_T->lock, _T->lock2)) +DECLARE_LOCK_GUARD_2_ATTRS(double_raw_spinlock, + __acquires(_T1, _T2), + __releases(*(raw_spinlock_t **)_T1), + __releases(*(raw_spinlock_t **)_T2)); +#define class_double_raw_spinlock_constructor(_T1, _T2) \ + WITH_LOCK_GUARD_2_ATTRS(double_raw_spinlock, _T1, _T2) + /* * double_rq_unlock - safely unlock two runqueues * @@ -3197,13 +3254,12 @@ DEFINE_LOCK_GUARD_2(double_raw_spinlock, raw_spinlock_t, * you need to do so manually after calling. */ static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2) - __releases(rq1->lock) - __releases(rq2->lock) + __releases(__rq_lockp(rq1), __rq_lockp(rq2)) { if (__rq_lockp(rq1) != __rq_lockp(rq2)) raw_spin_rq_unlock(rq2); else - __release(rq2->lock); + __release(__rq_lockp(rq2)); /* fake release */ raw_spin_rq_unlock(rq1); } diff --git a/scripts/context-analysis-suppression.txt b/scripts/context-analysis-suppression.txt index df25c3d07a5b..fd8951d06706 100644 --- a/scripts/context-analysis-suppression.txt +++ b/scripts/context-analysis-suppression.txt @@ -26,6 +26,7 @@ src:*include/linux/refcount.h=emit src:*include/linux/rhashtable.h=emit src:*include/linux/rwlock*.h=emit src:*include/linux/rwsem.h=emit +src:*include/linux/sched*=emit src:*include/linux/seqlock*.h=emit src:*include/linux/spinlock*.h=emit src:*include/linux/srcu*.h=emit -- 2.52.0.322.g1dd061c0dc-goog
