diff options
Diffstat (limited to 'kernel/kprobes.c')
| -rw-r--r-- | kernel/kprobes.c | 58 |
1 files changed, 49 insertions, 9 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 1fbf466a29a..64aab081153 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -47,11 +47,17 @@ static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; +static atomic_t kprobe_count; DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */ static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; +static struct notifier_block kprobe_page_fault_nb = { + .notifier_call = kprobe_exceptions_notify, + .priority = 0x7fffffff /* we need to notified first */ +}; + #ifdef __ARCH_WANT_KPROBES_INSN_SLOT /* * kprobe->ainsn.insn points to the copy of the instruction to be @@ -368,16 +374,15 @@ static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) */ static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p) { - struct kprobe *kp; - if (p->break_handler) { - list_for_each_entry_rcu(kp, &old_p->list, list) { - if (kp->break_handler) - return -EEXIST; - } + if (old_p->break_handler) + return -EEXIST; list_add_tail_rcu(&p->list, &old_p->list); + old_p->break_handler = aggr_break_handler; } else list_add_rcu(&p->list, &old_p->list); + if (p->post_handler && !old_p->post_handler) + old_p->post_handler = aggr_post_handler; return 0; } @@ -390,9 +395,11 @@ static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p) copy_kprobe(p, ap); ap->addr = p->addr; ap->pre_handler = aggr_pre_handler; - ap->post_handler = aggr_post_handler; ap->fault_handler = aggr_fault_handler; - ap->break_handler = aggr_break_handler; + if (p->post_handler) + ap->post_handler = aggr_post_handler; + if (p->break_handler) + ap->break_handler = aggr_break_handler; INIT_LIST_HEAD(&ap->list); list_add_rcu(&p->list, &ap->list); @@ -464,6 +471,8 @@ static int __kprobes __register_kprobe(struct kprobe *p, old_p = get_kprobe(p->addr); if (old_p) { ret = register_aggr_kprobe(old_p, p); + if (!ret) + atomic_inc(&kprobe_count); goto out; } @@ -474,6 +483,10 @@ static int __kprobes __register_kprobe(struct kprobe *p, hlist_add_head_rcu(&p->hlist, &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); + if (atomic_add_return(1, &kprobe_count) == \ + (ARCH_INACTIVE_KPROBE_COUNT + 1)) + register_page_fault_notifier(&kprobe_page_fault_nb); + arch_arm_kprobe(p); out: @@ -536,14 +549,40 @@ valid_p: kfree(old_p); } arch_remove_kprobe(p); + } else { + mutex_lock(&kprobe_mutex); + if (p->break_handler) + old_p->break_handler = NULL; + if (p->post_handler){ + list_for_each_entry_rcu(list_p, &old_p->list, list){ + if (list_p->post_handler){ + cleanup_p = 2; + break; + } + } + if (cleanup_p == 0) + old_p->post_handler = NULL; + } + mutex_unlock(&kprobe_mutex); } + + /* Call unregister_page_fault_notifier() + * if no probes are active + */ + mutex_lock(&kprobe_mutex); + if (atomic_add_return(-1, &kprobe_count) == \ + ARCH_INACTIVE_KPROBE_COUNT) + unregister_page_fault_notifier(&kprobe_page_fault_nb); + mutex_unlock(&kprobe_mutex); + return; } static struct notifier_block kprobe_exceptions_nb = { .notifier_call = kprobe_exceptions_notify, - .priority = 0x7fffffff /* we need to notified first */ + .priority = 0x7fffffff /* we need to be notified first */ }; + int __kprobes register_jprobe(struct jprobe *jp) { /* Todo: Verify probepoint is a function entry point */ @@ -652,6 +691,7 @@ static int __init init_kprobes(void) INIT_HLIST_HEAD(&kprobe_table[i]); INIT_HLIST_HEAD(&kretprobe_inst_table[i]); } + atomic_set(&kprobe_count, 0); err = arch_init_kprobes(); if (!err) |