/* NOTE: change this value only with kprobe_mutex held */
static bool kprobes_all_disarmed;
-static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
+/* This protects kprobe_table and optimizing_list */
+static DEFINE_MUTEX(kprobe_mutex);
static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
static struct {
spinlock_t lock ____cacheline_aligned_in_smp;
/* We have preemption disabled.. so it is safe to use __ versions */
static inline void set_kprobe_instance(struct kprobe *kp)
{
- __get_cpu_var(kprobe_instance) = kp;
+ __this_cpu_write(kprobe_instance, kp);
}
static inline void reset_kprobe_instance(void)
{
- __get_cpu_var(kprobe_instance) = NULL;
+ __this_cpu_write(kprobe_instance, NULL);
}
/*
return p->pre_handler == aggr_pre_handler;
}
+/* Return true(!0) if the kprobe is unused */
+static inline int kprobe_unused(struct kprobe *p)
+{
+ return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
+ list_empty(&p->list);
+}
+
/*
* Keep all fields in the kprobe consistent
*/
-static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
+static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
{
- memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
- memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
+ memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
+ memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
}
#ifdef CONFIG_OPTPROBES
}
}
+/* Free optimized instructions and optimized_kprobe */
+static __kprobes void free_aggr_kprobe(struct kprobe *p)
+{
+ struct optimized_kprobe *op;
+
+ op = container_of(p, struct optimized_kprobe, kp);
+ arch_remove_optimized_kprobe(op);
+ arch_remove_kprobe(p);
+ kfree(op);
+}
+
/* Return true(!0) if the kprobe is ready for optimization. */
static inline int kprobe_optready(struct kprobe *p)
{
return 0;
}
+/* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */
+static inline int kprobe_disarmed(struct kprobe *p)
+{
+ struct optimized_kprobe *op;
+
+ /* If kprobe is not aggr/opt probe, just return kprobe is disabled */
+ if (!kprobe_aggrprobe(p))
+ return kprobe_disabled(p);
+
+ op = container_of(p, struct optimized_kprobe, kp);
+
+ return kprobe_disabled(p) && list_empty(&op->list);
+}
+
+/* Return true(!0) if the probe is queued on (un)optimizing lists */
+static int __kprobes kprobe_queued(struct kprobe *p)
+{
+ struct optimized_kprobe *op;
+
+ if (kprobe_aggrprobe(p)) {
+ op = container_of(p, struct optimized_kprobe, kp);
+ if (!list_empty(&op->list))
+ return 1;
+ }
+ return 0;
+}
+
/*
* Return an optimized kprobe whose optimizing code replaces
* instructions including addr (exclude breakpoint).
/* Optimization staging list, protected by kprobe_mutex */
static LIST_HEAD(optimizing_list);
+static LIST_HEAD(unoptimizing_list);
static void kprobe_optimizer(struct work_struct *work);
static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
+static DECLARE_COMPLETION(optimizer_comp);
#define OPTIMIZE_DELAY 5
-/* Kprobe jump optimizer */
-static __kprobes void kprobe_optimizer(struct work_struct *work)
+/*
+ * Optimize (replace a breakpoint with a jump) kprobes listed on
+ * optimizing_list.
+ */
+static __kprobes void do_optimize_kprobes(void)
{
- struct optimized_kprobe *op, *tmp;
-
- /* Lock modules while optimizing kprobes */
- mutex_lock(&module_mutex);
- mutex_lock(&kprobe_mutex);
- if (kprobes_all_disarmed || !kprobes_allow_optimization)
- goto end;
-
- /*
- * Wait for quiesence period to ensure all running interrupts
- * are done. Because optprobe may modify multiple instructions
- * there is a chance that Nth instruction is interrupted. In that
- * case, running interrupt can return to 2nd-Nth byte of jump
- * instruction. This wait is for avoiding it.
- */
- synchronize_sched();
+ /* Optimization never be done when disarmed */
+ if (kprobes_all_disarmed || !kprobes_allow_optimization ||
+ list_empty(&optimizing_list))
+ return;
/*
* The optimization/unoptimization refers online_cpus via
*/
get_online_cpus();
mutex_lock(&text_mutex);
- list_for_each_entry_safe(op, tmp, &optimizing_list, list) {
- WARN_ON(kprobe_disabled(&op->kp));
- if (arch_optimize_kprobe(op) < 0)
- op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
- list_del_init(&op->list);
+ arch_optimize_kprobes(&optimizing_list);
+ mutex_unlock(&text_mutex);
+ put_online_cpus();
+}
+
+/*
+ * Unoptimize (replace a jump with a breakpoint and remove the breakpoint
+ * if need) kprobes listed on unoptimizing_list.
+ */
+static __kprobes void do_unoptimize_kprobes(struct list_head *free_list)
+{
+ struct optimized_kprobe *op, *tmp;
+
+ /* Unoptimization must be done anytime */
+ if (list_empty(&unoptimizing_list))
+ return;
+
+ /* Ditto to do_optimize_kprobes */
+ get_online_cpus();
+ mutex_lock(&text_mutex);
+ arch_unoptimize_kprobes(&unoptimizing_list, free_list);
+ /* Loop free_list for disarming */
+ list_for_each_entry_safe(op, tmp, free_list, list) {
+ /* Disarm probes if marked disabled */
+ if (kprobe_disabled(&op->kp))
+ arch_disarm_kprobe(&op->kp);
+ if (kprobe_unused(&op->kp)) {
+ /*
+ * Remove unused probes from hash list. After waiting
+ * for synchronization, these probes are reclaimed.
+ * (reclaiming is done by do_free_cleaned_kprobes.)
+ */
+ hlist_del_rcu(&op->kp.hlist);
+ } else
+ list_del_init(&op->list);
}
mutex_unlock(&text_mutex);
put_online_cpus();
-end:
+}
+
+/* Reclaim all kprobes on the free_list */
+static __kprobes void do_free_cleaned_kprobes(struct list_head *free_list)
+{
+ struct optimized_kprobe *op, *tmp;
+
+ list_for_each_entry_safe(op, tmp, free_list, list) {
+ BUG_ON(!kprobe_unused(&op->kp));
+ list_del_init(&op->list);
+ free_aggr_kprobe(&op->kp);
+ }
+}
+
+/* Start optimizer after OPTIMIZE_DELAY passed */
+static __kprobes void kick_kprobe_optimizer(void)
+{
+ if (!delayed_work_pending(&optimizing_work))
+ schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
+}
+
+/* Kprobe jump optimizer */
+static __kprobes void kprobe_optimizer(struct work_struct *work)
+{
+ LIST_HEAD(free_list);
+
+ /* Lock modules while optimizing kprobes */
+ mutex_lock(&module_mutex);
+ mutex_lock(&kprobe_mutex);
+
+ /*
+ * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
+ * kprobes before waiting for quiesence period.
+ */
+ do_unoptimize_kprobes(&free_list);
+
+ /*
+ * Step 2: Wait for quiesence period to ensure all running interrupts
+ * are done. Because optprobe may modify multiple instructions
+ * there is a chance that Nth instruction is interrupted. In that
+ * case, running interrupt can return to 2nd-Nth byte of jump
+ * instruction. This wait is for avoiding it.
+ */
+ synchronize_sched();
+
+ /* Step 3: Optimize kprobes after quiesence period */
+ do_optimize_kprobes();
+
+ /* Step 4: Free cleaned kprobes after quiesence period */
+ do_free_cleaned_kprobes(&free_list);
+
mutex_unlock(&kprobe_mutex);
mutex_unlock(&module_mutex);
+
+ /* Step 5: Kick optimizer again if needed */
+ if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
+ kick_kprobe_optimizer();
+ else
+ /* Wake up all waiters */
+ complete_all(&optimizer_comp);
+}
+
+/* Wait for completing optimization and unoptimization */
+static __kprobes void wait_for_kprobe_optimizer(void)
+{
+ if (delayed_work_pending(&optimizing_work))
+ wait_for_completion(&optimizer_comp);
}
/* Optimize kprobe if p is ready to be optimized */
/* Check if it is already optimized. */
if (op->kp.flags & KPROBE_FLAG_OPTIMIZED)
return;
-
op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
- list_add(&op->list, &optimizing_list);
- if (!delayed_work_pending(&optimizing_work))
- schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
+
+ if (!list_empty(&op->list))
+ /* This is under unoptimizing. Just dequeue the probe */
+ list_del_init(&op->list);
+ else {
+ list_add(&op->list, &optimizing_list);
+ kick_kprobe_optimizer();
+ }
+}
+
+/* Short cut to direct unoptimizing */
+static __kprobes void force_unoptimize_kprobe(struct optimized_kprobe *op)
+{
+ get_online_cpus();
+ arch_unoptimize_kprobe(op);
+ put_online_cpus();
+ if (kprobe_disabled(&op->kp))
+ arch_disarm_kprobe(&op->kp);
}
/* Unoptimize a kprobe if p is optimized */
-static __kprobes void unoptimize_kprobe(struct kprobe *p)
+static __kprobes void unoptimize_kprobe(struct kprobe *p, bool force)
{
struct optimized_kprobe *op;
- if ((p->flags & KPROBE_FLAG_OPTIMIZED) && kprobe_aggrprobe(p)) {
- op = container_of(p, struct optimized_kprobe, kp);
- if (!list_empty(&op->list))
- /* Dequeue from the optimization queue */
+ if (!kprobe_aggrprobe(p) || kprobe_disarmed(p))
+ return; /* This is not an optprobe nor optimized */
+
+ op = container_of(p, struct optimized_kprobe, kp);
+ if (!kprobe_optimized(p)) {
+ /* Unoptimized or unoptimizing case */
+ if (force && !list_empty(&op->list)) {
+ /*
+ * Only if this is unoptimizing kprobe and forced,
+ * forcibly unoptimize it. (No need to unoptimize
+ * unoptimized kprobe again :)
+ */
list_del_init(&op->list);
- else
- /* Replace jump with break */
- arch_unoptimize_kprobe(op);
- op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
+ force_unoptimize_kprobe(op);
+ }
+ return;
+ }
+
+ op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
+ if (!list_empty(&op->list)) {
+ /* Dequeue from the optimization queue */
+ list_del_init(&op->list);
+ return;
+ }
+ /* Optimized kprobe case */
+ if (force)
+ /* Forcibly update the code: this is a special case */
+ force_unoptimize_kprobe(op);
+ else {
+ list_add(&op->list, &unoptimizing_list);
+ kick_kprobe_optimizer();
}
}
+/* Cancel unoptimizing for reusing */
+static void reuse_unused_kprobe(struct kprobe *ap)
+{
+ struct optimized_kprobe *op;
+
+ BUG_ON(!kprobe_unused(ap));
+ /*
+ * Unused kprobe MUST be on the way of delayed unoptimizing (means
+ * there is still a relative jump) and disabled.
+ */
+ op = container_of(ap, struct optimized_kprobe, kp);
+ if (unlikely(list_empty(&op->list)))
+ printk(KERN_WARNING "Warning: found a stray unused "
+ "aggrprobe@%p\n", ap->addr);
+ /* Enable the probe again */
+ ap->flags &= ~KPROBE_FLAG_DISABLED;
+ /* Optimize it again (remove from op->list) */
+ BUG_ON(!kprobe_optready(ap));
+ optimize_kprobe(ap);
+}
+
/* Remove optimized instructions */
static void __kprobes kill_optimized_kprobe(struct kprobe *p)
{
struct optimized_kprobe *op;
op = container_of(p, struct optimized_kprobe, kp);
- if (!list_empty(&op->list)) {
- /* Dequeue from the optimization queue */
+ if (!list_empty(&op->list))
+ /* Dequeue from the (un)optimization queue */
list_del_init(&op->list);
- op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
- }
- /* Don't unoptimize, because the target code will be freed. */
+
+ op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
+ /* Don't touch the code, because it is already freed. */
arch_remove_optimized_kprobe(op);
}
arch_prepare_optimized_kprobe(op);
}
-/* Free optimized instructions and optimized_kprobe */
-static __kprobes void free_aggr_kprobe(struct kprobe *p)
-{
- struct optimized_kprobe *op;
-
- op = container_of(p, struct optimized_kprobe, kp);
- arch_remove_optimized_kprobe(op);
- kfree(op);
-}
-
/* Allocate new optimized_kprobe and try to prepare optimized instructions */
static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
{
op = container_of(ap, struct optimized_kprobe, kp);
if (!arch_prepared_optinsn(&op->optinsn)) {
/* If failed to setup optimizing, fallback to kprobe */
- free_aggr_kprobe(ap);
+ arch_remove_optimized_kprobe(op);
+ kfree(op);
return;
}
}
#ifdef CONFIG_SYSCTL
+/* This should be called with kprobe_mutex locked */
static void __kprobes optimize_all_kprobes(void)
{
struct hlist_head *head;
return;
kprobes_allow_optimization = true;
- mutex_lock(&text_mutex);
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry_rcu(p, node, head, hlist)
if (!kprobe_disabled(p))
optimize_kprobe(p);
}
- mutex_unlock(&text_mutex);
printk(KERN_INFO "Kprobes globally optimized\n");
}
+/* This should be called with kprobe_mutex locked */
static void __kprobes unoptimize_all_kprobes(void)
{
struct hlist_head *head;
return;
kprobes_allow_optimization = false;
- printk(KERN_INFO "Kprobes globally unoptimized\n");
- get_online_cpus(); /* For avoiding text_mutex deadlock */
- mutex_lock(&text_mutex);
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry_rcu(p, node, head, hlist) {
if (!kprobe_disabled(p))
- unoptimize_kprobe(p);
+ unoptimize_kprobe(p, false);
}
}
-
- mutex_unlock(&text_mutex);
- put_online_cpus();
- /* Allow all currently running kprobes to complete */
- synchronize_sched();
+ /* Wait for unoptimizing completion */
+ wait_for_kprobe_optimizer();
+ printk(KERN_INFO "Kprobes globally unoptimized\n");
}
int sysctl_kprobes_optimization;
}
#endif /* CONFIG_SYSCTL */
+/* Put a breakpoint for a probe. Must be called with text_mutex locked */
static void __kprobes __arm_kprobe(struct kprobe *p)
{
- struct kprobe *old_p;
+ struct kprobe *_p;
/* Check collision with other optimized kprobes */
- old_p = get_optimized_kprobe((unsigned long)p->addr);
- if (unlikely(old_p))
- unoptimize_kprobe(old_p); /* Fallback to unoptimized kprobe */
+ _p = get_optimized_kprobe((unsigned long)p->addr);
+ if (unlikely(_p))
+ /* Fallback to unoptimized kprobe */
+ unoptimize_kprobe(_p, true);
arch_arm_kprobe(p);
optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
}
-static void __kprobes __disarm_kprobe(struct kprobe *p)
+/* Remove the breakpoint of a probe. Must be called with text_mutex locked */
+static void __kprobes __disarm_kprobe(struct kprobe *p, bool reopt)
{
- struct kprobe *old_p;
+ struct kprobe *_p;
- unoptimize_kprobe(p); /* Try to unoptimize */
- arch_disarm_kprobe(p);
+ unoptimize_kprobe(p, false); /* Try to unoptimize */
- /* If another kprobe was blocked, optimize it. */
- old_p = get_optimized_kprobe((unsigned long)p->addr);
- if (unlikely(old_p))
- optimize_kprobe(old_p);
+ if (!kprobe_queued(p)) {
+ arch_disarm_kprobe(p);
+ /* If another kprobe was blocked, optimize it. */
+ _p = get_optimized_kprobe((unsigned long)p->addr);
+ if (unlikely(_p) && reopt)
+ optimize_kprobe(_p);
+ }
+ /* TODO: reoptimize others after unoptimized this probe */
}
#else /* !CONFIG_OPTPROBES */
#define optimize_kprobe(p) do {} while (0)
-#define unoptimize_kprobe(p) do {} while (0)
+#define unoptimize_kprobe(p, f) do {} while (0)
#define kill_optimized_kprobe(p) do {} while (0)
#define prepare_optimized_kprobe(p) do {} while (0)
#define try_to_optimize_kprobe(p) do {} while (0)
#define __arm_kprobe(p) arch_arm_kprobe(p)
-#define __disarm_kprobe(p) arch_disarm_kprobe(p)
+#define __disarm_kprobe(p, o) arch_disarm_kprobe(p)
+#define kprobe_disarmed(p) kprobe_disabled(p)
+#define wait_for_kprobe_optimizer() do {} while (0)
+
+/* There should be no unused kprobes can be reused without optimization */
+static void reuse_unused_kprobe(struct kprobe *ap)
+{
+ printk(KERN_ERR "Error: There should be no unused kprobe here.\n");
+ BUG_ON(kprobe_unused(ap));
+}
static __kprobes void free_aggr_kprobe(struct kprobe *p)
{
+ arch_remove_kprobe(p);
kfree(p);
}
/* Disarm a kprobe with text_mutex */
static void __kprobes disarm_kprobe(struct kprobe *kp)
{
- get_online_cpus(); /* For avoiding text_mutex deadlock */
+ /* Ditto */
mutex_lock(&text_mutex);
- __disarm_kprobe(kp);
+ __disarm_kprobe(kp, true);
mutex_unlock(&text_mutex);
- put_online_cpus();
}
/*
static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
int trapnr)
{
- struct kprobe *cur = __get_cpu_var(kprobe_instance);
+ struct kprobe *cur = __this_cpu_read(kprobe_instance);
/*
* if we faulted "during" the execution of a user specified
static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
{
- struct kprobe *cur = __get_cpu_var(kprobe_instance);
+ struct kprobe *cur = __this_cpu_read(kprobe_instance);
int ret = 0;
if (cur && cur->break_handler) {
BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
if (p->break_handler || p->post_handler)
- unoptimize_kprobe(ap); /* Fall back to normal kprobe */
+ unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */
if (p->break_handler) {
if (ap->break_handler)
* This is the second or subsequent kprobe at the address - handle
* the intricacies
*/
-static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
+static int __kprobes register_aggr_kprobe(struct kprobe *orig_p,
struct kprobe *p)
{
int ret = 0;
- struct kprobe *ap = old_p;
+ struct kprobe *ap = orig_p;
- if (!kprobe_aggrprobe(old_p)) {
- /* If old_p is not an aggr_kprobe, create new aggr_kprobe. */
- ap = alloc_aggr_kprobe(old_p);
+ if (!kprobe_aggrprobe(orig_p)) {
+ /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
+ ap = alloc_aggr_kprobe(orig_p);
if (!ap)
return -ENOMEM;
- init_aggr_kprobe(ap, old_p);
- }
+ init_aggr_kprobe(ap, orig_p);
+ } else if (kprobe_unused(ap))
+ /* This probe is going to die. Rescue it */
+ reuse_unused_kprobe(ap);
if (kprobe_gone(ap)) {
/*
return add_new_kprobe(ap, p);
}
-/* Try to disable aggr_kprobe, and return 1 if succeeded.*/
-static int __kprobes try_to_disable_aggr_kprobe(struct kprobe *p)
-{
- struct kprobe *kp;
-
- list_for_each_entry_rcu(kp, &p->list, list) {
- if (!kprobe_disabled(kp))
- /*
- * There is an active probe on the list.
- * We can't disable aggr_kprobe.
- */
- return 0;
- }
- p->flags |= KPROBE_FLAG_DISABLED;
- return 1;
-}
-
static int __kprobes in_kprobes_functions(unsigned long addr)
{
struct kprobe_blackpoint *kb;
/*
* If we have a symbol_name argument, look it up and add the offset field
* to it. This way, we can specify a relative address to a symbol.
+ * This returns encoded errors if it fails to look up symbol or invalid
+ * combination of parameters.
*/
static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
{
kprobe_opcode_t *addr = p->addr;
+
+ if ((p->symbol_name && p->addr) ||
+ (!p->symbol_name && !p->addr))
+ goto invalid;
+
if (p->symbol_name) {
- if (addr)
- return NULL;
kprobe_lookup_name(p->symbol_name, addr);
+ if (!addr)
+ return ERR_PTR(-ENOENT);
}
- if (!addr)
- return NULL;
- return (kprobe_opcode_t *)(((char *)addr) + p->offset);
+ addr = (kprobe_opcode_t *)(((char *)addr) + p->offset);
+ if (addr)
+ return addr;
+
+invalid:
+ return ERR_PTR(-EINVAL);
}
/* Check passed kprobe is valid and return kprobe in kprobe_table. */
static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p)
{
- struct kprobe *old_p, *list_p;
+ struct kprobe *ap, *list_p;
- old_p = get_kprobe(p->addr);
- if (unlikely(!old_p))
+ ap = get_kprobe(p->addr);
+ if (unlikely(!ap))
return NULL;
- if (p != old_p) {
- list_for_each_entry_rcu(list_p, &old_p->list, list)
+ if (p != ap) {
+ list_for_each_entry_rcu(list_p, &ap->list, list)
if (list_p == p)
/* kprobe p is a valid probe */
goto valid;
return NULL;
}
valid:
- return old_p;
+ return ap;
}
/* Return error if the kprobe is being re-registered */
static inline int check_kprobe_rereg(struct kprobe *p)
{
int ret = 0;
- struct kprobe *old_p;
mutex_lock(&kprobe_mutex);
- old_p = __get_valid_kprobe(p);
- if (old_p)
+ if (__get_valid_kprobe(p))
ret = -EINVAL;
mutex_unlock(&kprobe_mutex);
+
return ret;
}
kprobe_opcode_t *addr;
addr = kprobe_addr(p);
- if (!addr)
- return -EINVAL;
+ if (IS_ERR(addr))
+ return PTR_ERR(addr);
p->addr = addr;
ret = check_kprobe_rereg(p);
if (ret)
return ret;
+ jump_label_lock();
preempt_disable();
if (!kernel_text_address((unsigned long) p->addr) ||
in_kprobes_functions((unsigned long) p->addr) ||
ftrace_text_reserved(p->addr, p->addr) ||
- jump_label_text_reserved(p->addr, p->addr)) {
- preempt_enable();
- return -EINVAL;
- }
+ jump_label_text_reserved(p->addr, p->addr))
+ goto fail_with_jump_label;
/* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
p->flags &= KPROBE_FLAG_DISABLED;
*/
probed_mod = __module_text_address((unsigned long) p->addr);
if (probed_mod) {
+ /* Return -ENOENT if fail. */
+ ret = -ENOENT;
/*
* We must hold a refcount of the probed module while updating
* its code to prohibit unexpected unloading.
*/
- if (unlikely(!try_module_get(probed_mod))) {
- preempt_enable();
- return -EINVAL;
- }
+ if (unlikely(!try_module_get(probed_mod)))
+ goto fail_with_jump_label;
+
/*
* If the module freed .init.text, we couldn't insert
* kprobes in there.
if (within_module_init((unsigned long)p->addr, probed_mod) &&
probed_mod->state != MODULE_STATE_COMING) {
module_put(probed_mod);
- preempt_enable();
- return -EINVAL;
+ goto fail_with_jump_label;
}
+ /* ret will be updated by following code */
}
preempt_enable();
+ jump_label_unlock();
p->nmissed = 0;
INIT_LIST_HEAD(&p->list);
mutex_lock(&kprobe_mutex);
+ jump_label_lock(); /* needed to call jump_label_text_reserved() */
+
get_online_cpus(); /* For avoiding text_mutex deadlock. */
mutex_lock(&text_mutex);
out:
mutex_unlock(&text_mutex);
put_online_cpus();
+ jump_label_unlock();
mutex_unlock(&kprobe_mutex);
if (probed_mod)
module_put(probed_mod);
return ret;
+
+fail_with_jump_label:
+ preempt_enable();
+ jump_label_unlock();
+ return ret;
}
EXPORT_SYMBOL_GPL(register_kprobe);
+/* Check if all probes on the aggrprobe are disabled */
+static int __kprobes aggr_kprobe_disabled(struct kprobe *ap)
+{
+ struct kprobe *kp;
+
+ list_for_each_entry_rcu(kp, &ap->list, list)
+ if (!kprobe_disabled(kp))
+ /*
+ * There is an active probe on the list.
+ * We can't disable this ap.
+ */
+ return 0;
+
+ return 1;
+}
+
+/* Disable one kprobe: Make sure called under kprobe_mutex is locked */
+static struct kprobe *__kprobes __disable_kprobe(struct kprobe *p)
+{
+ struct kprobe *orig_p;
+
+ /* Get an original kprobe for return */
+ orig_p = __get_valid_kprobe(p);
+ if (unlikely(orig_p == NULL))
+ return NULL;
+
+ if (!kprobe_disabled(p)) {
+ /* Disable probe if it is a child probe */
+ if (p != orig_p)
+ p->flags |= KPROBE_FLAG_DISABLED;
+
+ /* Try to disarm and disable this/parent probe */
+ if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
+ disarm_kprobe(orig_p);
+ orig_p->flags |= KPROBE_FLAG_DISABLED;
+ }
+ }
+
+ return orig_p;
+}
+
/*
* Unregister a kprobe without a scheduler synchronization.
*/
static int __kprobes __unregister_kprobe_top(struct kprobe *p)
{
- struct kprobe *old_p, *list_p;
+ struct kprobe *ap, *list_p;
- old_p = __get_valid_kprobe(p);
- if (old_p == NULL)
+ /* Disable kprobe. This will disarm it if needed. */
+ ap = __disable_kprobe(p);
+ if (ap == NULL)
return -EINVAL;
- if (old_p == p ||
- (kprobe_aggrprobe(old_p) &&
- list_is_singular(&old_p->list))) {
+ if (ap == p)
/*
- * Only probe on the hash list. Disarm only if kprobes are
- * enabled and not gone - otherwise, the breakpoint would
- * already have been removed. We save on flushing icache.
+ * This probe is an independent(and non-optimized) kprobe
+ * (not an aggrprobe). Remove from the hash list.
*/
- if (!kprobes_all_disarmed && !kprobe_disabled(old_p))
- disarm_kprobe(old_p);
- hlist_del_rcu(&old_p->hlist);
- } else {
+ goto disarmed;
+
+ /* Following process expects this probe is an aggrprobe */
+ WARN_ON(!kprobe_aggrprobe(ap));
+
+ if (list_is_singular(&ap->list) && kprobe_disarmed(ap))
+ /*
+ * !disarmed could be happen if the probe is under delayed
+ * unoptimizing.
+ */
+ goto disarmed;
+ else {
+ /* If disabling probe has special handlers, update aggrprobe */
if (p->break_handler && !kprobe_gone(p))
- old_p->break_handler = NULL;
+ ap->break_handler = NULL;
if (p->post_handler && !kprobe_gone(p)) {
- list_for_each_entry_rcu(list_p, &old_p->list, list) {
+ list_for_each_entry_rcu(list_p, &ap->list, list) {
if ((list_p != p) && (list_p->post_handler))
goto noclean;
}
- old_p->post_handler = NULL;
+ ap->post_handler = NULL;
}
noclean:
+ /*
+ * Remove from the aggrprobe: this path will do nothing in
+ * __unregister_kprobe_bottom().
+ */
list_del_rcu(&p->list);
- if (!kprobe_disabled(old_p)) {
- try_to_disable_aggr_kprobe(old_p);
- if (!kprobes_all_disarmed) {
- if (kprobe_disabled(old_p))
- disarm_kprobe(old_p);
- else
- /* Try to optimize this probe again */
- optimize_kprobe(old_p);
- }
- }
+ if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
+ /*
+ * Try to optimize this probe again, because post
+ * handler may have been changed.
+ */
+ optimize_kprobe(ap);
}
return 0;
+
+disarmed:
+ BUG_ON(!kprobe_disarmed(ap));
+ hlist_del_rcu(&ap->hlist);
+ return 0;
}
static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
{
- struct kprobe *old_p;
+ struct kprobe *ap;
if (list_empty(&p->list))
+ /* This is an independent kprobe */
arch_remove_kprobe(p);
else if (list_is_singular(&p->list)) {
- /* "p" is the last child of an aggr_kprobe */
- old_p = list_entry(p->list.next, struct kprobe, list);
+ /* This is the last child of an aggrprobe */
+ ap = list_entry(p->list.next, struct kprobe, list);
list_del(&p->list);
- arch_remove_kprobe(old_p);
- free_aggr_kprobe(old_p);
+ free_aggr_kprobe(ap);
}
+ /* Otherwise, do nothing. */
}
int __kprobes register_kprobes(struct kprobe **kps, int num)
if (kretprobe_blacklist_size) {
addr = kprobe_addr(&rp->kp);
- if (!addr)
- return -EINVAL;
+ if (IS_ERR(addr))
+ return PTR_ERR(addr);
for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
if (kretprobe_blacklist[i].addr == addr)
int __kprobes disable_kprobe(struct kprobe *kp)
{
int ret = 0;
- struct kprobe *p;
mutex_lock(&kprobe_mutex);
- /* Check whether specified probe is valid. */
- p = __get_valid_kprobe(kp);
- if (unlikely(p == NULL)) {
+ /* Disable this kprobe */
+ if (__disable_kprobe(kp) == NULL)
ret = -EINVAL;
- goto out;
- }
- /* If the probe is already disabled (or gone), just return */
- if (kprobe_disabled(kp))
- goto out;
-
- kp->flags |= KPROBE_FLAG_DISABLED;
- if (p != kp)
- /* When kp != p, p is always enabled. */
- try_to_disable_aggr_kprobe(p);
-
- if (!kprobes_all_disarmed && kprobe_disabled(p))
- disarm_kprobe(p);
-out:
mutex_unlock(&kprobe_mutex);
return ret;
}
mutex_lock(&kprobe_mutex);
/* If kprobes are already disarmed, just return */
- if (kprobes_all_disarmed)
- goto already_disabled;
+ if (kprobes_all_disarmed) {
+ mutex_unlock(&kprobe_mutex);
+ return;
+ }
kprobes_all_disarmed = true;
printk(KERN_INFO "Kprobes globally disabled\n");
- /*
- * Here we call get_online_cpus() for avoiding text_mutex deadlock,
- * because disarming may also unoptimize kprobes.
- */
- get_online_cpus();
mutex_lock(&text_mutex);
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry_rcu(p, node, head, hlist) {
if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
- __disarm_kprobe(p);
+ __disarm_kprobe(p, false);
}
}
-
mutex_unlock(&text_mutex);
- put_online_cpus();
mutex_unlock(&kprobe_mutex);
- /* Allow all currently running kprobes to complete */
- synchronize_sched();
- return;
-already_disabled:
- mutex_unlock(&kprobe_mutex);
- return;
+ /* Wait for disarming all kprobes by optimizer */
+ wait_for_kprobe_optimizer();
}
/*
Code Review / linux-2.6.git / blobdiff