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Commit ec484608 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
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locking, kprobes: Annotate the hash locks and kretprobe.lock as raw 



The kprobe locks can be taken in atomic context and therefore
cannot be preempted on -rt - annotate it.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 76bf6877

include/linux/kprobes.h

+1 −1
Original line number Diff line number Diff line
@@ -181,7 +181,7 @@ struct kretprobe { 
	int nmissed;

	size_t data_size;

	struct hlist_head free_instances;

	spinlock_t lock;

	raw_spinlock_t lock;

};



struct kretprobe_instance {

kernel/kprobes.c

+17 −17
Original line number Diff line number Diff line
@@ -78,10 +78,10 @@ static bool kprobes_all_disarmed; 
static DEFINE_MUTEX(kprobe_mutex);

static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;

static struct {

	spinlock_t lock ____cacheline_aligned_in_smp;

	raw_spinlock_t lock ____cacheline_aligned_in_smp;

} kretprobe_table_locks[KPROBE_TABLE_SIZE];



static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)

static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)

{

	return &(kretprobe_table_locks[hash].lock);

}
@@ -1013,9 +1013,9 @@ void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, 
	hlist_del(&ri->hlist);

	INIT_HLIST_NODE(&ri->hlist);

	if (likely(rp)) {

		spin_lock(&rp->lock);

		raw_spin_lock(&rp->lock);

		hlist_add_head(&ri->hlist, &rp->free_instances);

		spin_unlock(&rp->lock);

		raw_spin_unlock(&rp->lock);

	} else

		/* Unregistering */

		hlist_add_head(&ri->hlist, head);
@@ -1026,19 +1026,19 @@ void __kprobes kretprobe_hash_lock(struct task_struct *tsk, 
__acquires(hlist_lock)

{

	unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);

	spinlock_t *hlist_lock;

	raw_spinlock_t *hlist_lock;



	*head = &kretprobe_inst_table[hash];

	hlist_lock = kretprobe_table_lock_ptr(hash);

	spin_lock_irqsave(hlist_lock, *flags);

	raw_spin_lock_irqsave(hlist_lock, *flags);

}



static void __kprobes kretprobe_table_lock(unsigned long hash,

	unsigned long *flags)

__acquires(hlist_lock)

{

	spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);

	spin_lock_irqsave(hlist_lock, *flags);

	raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);

	raw_spin_lock_irqsave(hlist_lock, *flags);

}



void __kprobes kretprobe_hash_unlock(struct task_struct *tsk,
@@ -1046,18 +1046,18 @@ void __kprobes kretprobe_hash_unlock(struct task_struct *tsk, 
__releases(hlist_lock)

{

	unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);

	spinlock_t *hlist_lock;

	raw_spinlock_t *hlist_lock;



	hlist_lock = kretprobe_table_lock_ptr(hash);

	spin_unlock_irqrestore(hlist_lock, *flags);

	raw_spin_unlock_irqrestore(hlist_lock, *flags);

}



static void __kprobes kretprobe_table_unlock(unsigned long hash,

       unsigned long *flags)

__releases(hlist_lock)

{

	spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);

	spin_unlock_irqrestore(hlist_lock, *flags);

	raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);

	raw_spin_unlock_irqrestore(hlist_lock, *flags);

}



/*
@@ -1663,12 +1663,12 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p, 


	/*TODO: consider to only swap the RA after the last pre_handler fired */

	hash = hash_ptr(current, KPROBE_HASH_BITS);

	spin_lock_irqsave(&rp->lock, flags);

	raw_spin_lock_irqsave(&rp->lock, flags);

	if (!hlist_empty(&rp->free_instances)) {

		ri = hlist_entry(rp->free_instances.first,

				struct kretprobe_instance, hlist);

		hlist_del(&ri->hlist);

		spin_unlock_irqrestore(&rp->lock, flags);

		raw_spin_unlock_irqrestore(&rp->lock, flags);



		ri->rp = rp;

		ri->task = current;
@@ -1685,7 +1685,7 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p, 
		kretprobe_table_unlock(hash, &flags);

	} else {

		rp->nmissed++;

		spin_unlock_irqrestore(&rp->lock, flags);

		raw_spin_unlock_irqrestore(&rp->lock, flags);

	}

	return 0;

}
@@ -1721,7 +1721,7 @@ int __kprobes register_kretprobe(struct kretprobe *rp) 
		rp->maxactive = num_possible_cpus();

#endif

	}

	spin_lock_init(&rp->lock);

	raw_spin_lock_init(&rp->lock);

	INIT_HLIST_HEAD(&rp->free_instances);

	for (i = 0; i < rp->maxactive; i++) {

		inst = kmalloc(sizeof(struct kretprobe_instance) +
@@ -1959,7 +1959,7 @@ static int __init init_kprobes(void) 
	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {

		INIT_HLIST_HEAD(&kprobe_table[i]);

		INIT_HLIST_HEAD(&kretprobe_inst_table[i]);

		spin_lock_init(&(kretprobe_table_locks[i].lock));

		raw_spin_lock_init(&(kretprobe_table_locks[i].lock));

	}



	/*