{
LIST_HEAD(free_list);
+ mutex_lock(&kprobe_mutex);
/* Lock modules while optimizing kprobes */
mutex_lock(&module_mutex);
- mutex_lock(&kprobe_mutex);
/*
* Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
/* Step 4: Free cleaned kprobes after quiesence period */
do_free_cleaned_kprobes(&free_list);
- mutex_unlock(&kprobe_mutex);
mutex_unlock(&module_mutex);
+ mutex_unlock(&kprobe_mutex);
/* Step 5: Kick optimizer again if needed */
if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
struct kprobe *ap;
struct optimized_kprobe *op;
+ /* Impossible to optimize ftrace-based kprobe */
+ if (kprobe_ftrace(p))
+ return;
+
+ /* For preparing optimization, jump_label_text_reserved() is called */
+ jump_label_lock();
+ mutex_lock(&text_mutex);
+
ap = alloc_aggr_kprobe(p);
if (!ap)
- return;
+ goto out;
op = container_of(ap, struct optimized_kprobe, kp);
if (!arch_prepared_optinsn(&op->optinsn)) {
/* If failed to setup optimizing, fallback to kprobe */
arch_remove_optimized_kprobe(op);
kfree(op);
- return;
+ goto out;
}
init_aggr_kprobe(ap, p);
- optimize_kprobe(ap);
+ optimize_kprobe(ap); /* This just kicks optimizer thread */
+
+out:
+ mutex_unlock(&text_mutex);
+ jump_label_unlock();
}
#ifdef CONFIG_SYSCTL
}
#endif /* CONFIG_OPTPROBES */
+#ifdef KPROBES_CAN_USE_FTRACE
+static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
+ .func = kprobe_ftrace_handler,
+ .flags = FTRACE_OPS_FL_SAVE_REGS,
+};
+static int kprobe_ftrace_enabled;
+
+/* Must ensure p->addr is really on ftrace */
+static int __kprobes prepare_kprobe(struct kprobe *p)
+{
+ if (!kprobe_ftrace(p))
+ return arch_prepare_kprobe(p);
+
+ return arch_prepare_kprobe_ftrace(p);
+}
+
+/* Caller must lock kprobe_mutex */
+static void __kprobes arm_kprobe_ftrace(struct kprobe *p)
+{
+ int ret;
+
+ ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
+ (unsigned long)p->addr, 0, 0);
+ WARN(ret < 0, "Failed to arm kprobe-ftrace at %p (%d)\n", p->addr, ret);
+ kprobe_ftrace_enabled++;
+ if (kprobe_ftrace_enabled == 1) {
+ ret = register_ftrace_function(&kprobe_ftrace_ops);
+ WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret);
+ }
+}
+
+/* Caller must lock kprobe_mutex */
+static void __kprobes disarm_kprobe_ftrace(struct kprobe *p)
+{
+ int ret;
+
+ kprobe_ftrace_enabled--;
+ if (kprobe_ftrace_enabled == 0) {
+ ret = unregister_ftrace_function(&kprobe_ftrace_ops);
+ WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret);
+ }
+ ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
+ (unsigned long)p->addr, 1, 0);
+ WARN(ret < 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p->addr, ret);
+}
+#else /* !KPROBES_CAN_USE_FTRACE */
+#define prepare_kprobe(p) arch_prepare_kprobe(p)
+#define arm_kprobe_ftrace(p) do {} while (0)
+#define disarm_kprobe_ftrace(p) do {} while (0)
+#endif
+
/* Arm a kprobe with text_mutex */
static void __kprobes arm_kprobe(struct kprobe *kp)
{
+ if (unlikely(kprobe_ftrace(kp))) {
+ arm_kprobe_ftrace(kp);
+ return;
+ }
/*
* Here, since __arm_kprobe() doesn't use stop_machine(),
* this doesn't cause deadlock on text_mutex. So, we don't
}
/* Disarm a kprobe with text_mutex */
-static void __kprobes disarm_kprobe(struct kprobe *kp)
+static void __kprobes disarm_kprobe(struct kprobe *kp, bool reopt)
{
+ if (unlikely(kprobe_ftrace(kp))) {
+ disarm_kprobe_ftrace(kp);
+ return;
+ }
/* Ditto */
mutex_lock(&text_mutex);
- __disarm_kprobe(kp, true);
+ __disarm_kprobe(kp, reopt);
mutex_unlock(&text_mutex);
}
if (p->post_handler && !ap->post_handler)
ap->post_handler = aggr_post_handler;
- if (kprobe_disabled(ap) && !kprobe_disabled(p)) {
- ap->flags &= ~KPROBE_FLAG_DISABLED;
- if (!kprobes_all_disarmed)
- /* Arm the breakpoint again. */
- __arm_kprobe(ap);
- }
return 0;
}
int ret = 0;
struct kprobe *ap = orig_p;
+ /* For preparing optimization, jump_label_text_reserved() is called */
+ jump_label_lock();
+ /*
+ * Get online CPUs to avoid text_mutex deadlock.with stop machine,
+ * which is invoked by unoptimize_kprobe() in add_new_kprobe()
+ */
+ get_online_cpus();
+ mutex_lock(&text_mutex);
+
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;
+ if (!ap) {
+ ret = -ENOMEM;
+ goto out;
+ }
init_aggr_kprobe(ap, orig_p);
} else if (kprobe_unused(ap))
/* This probe is going to die. Rescue it */
* free aggr_probe. It will be used next time, or
* freed by unregister_kprobe.
*/
- return ret;
+ goto out;
/* Prepare optimized instructions if possible. */
prepare_optimized_kprobe(ap);
/* Copy ap's insn slot to p */
copy_kprobe(ap, p);
- return add_new_kprobe(ap, p);
+ ret = add_new_kprobe(ap, p);
+
+out:
+ mutex_unlock(&text_mutex);
+ put_online_cpus();
+ jump_label_unlock();
+
+ if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) {
+ ap->flags &= ~KPROBE_FLAG_DISABLED;
+ if (!kprobes_all_disarmed)
+ /* Arm the breakpoint again. */
+ arm_kprobe(ap);
+ }
+ return ret;
}
static int __kprobes in_kprobes_functions(unsigned long addr)
return ret;
}
-int __kprobes register_kprobe(struct kprobe *p)
+static __kprobes int check_kprobe_address_safe(struct kprobe *p,
+ struct module **probed_mod)
{
int ret = 0;
- struct kprobe *old_p;
- struct module *probed_mod;
- kprobe_opcode_t *addr;
-
- addr = kprobe_addr(p);
- if (IS_ERR(addr))
- return PTR_ERR(addr);
- p->addr = addr;
+ unsigned long ftrace_addr;
- ret = check_kprobe_rereg(p);
- if (ret)
- return ret;
+ /*
+ * If the address is located on a ftrace nop, set the
+ * breakpoint to the following instruction.
+ */
+ ftrace_addr = ftrace_location((unsigned long)p->addr);
+ if (ftrace_addr) {
+#ifdef KPROBES_CAN_USE_FTRACE
+ /* Given address is not on the instruction boundary */
+ if ((unsigned long)p->addr != ftrace_addr)
+ return -EILSEQ;
+ p->flags |= KPROBE_FLAG_FTRACE;
+#else /* !KPROBES_CAN_USE_FTRACE */
+ return -EINVAL;
+#endif
+ }
jump_label_lock();
preempt_disable();
+
+ /* Ensure it is not in reserved area nor out of text */
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)) {
ret = -EINVAL;
- goto cannot_probe;
+ goto out;
}
- /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
- p->flags &= KPROBE_FLAG_DISABLED;
-
- /*
- * Check if are we probing a module.
- */
- probed_mod = __module_text_address((unsigned long) p->addr);
- if (probed_mod) {
- /* Return -ENOENT if fail. */
- ret = -ENOENT;
+ /* Check if are we probing a module */
+ *probed_mod = __module_text_address((unsigned long) p->addr);
+ if (*probed_mod) {
/*
* We must hold a refcount of the probed module while updating
* its code to prohibit unexpected unloading.
*/
- if (unlikely(!try_module_get(probed_mod)))
- goto cannot_probe;
+ if (unlikely(!try_module_get(*probed_mod))) {
+ ret = -ENOENT;
+ goto out;
+ }
/*
* 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);
- goto cannot_probe;
+ if (within_module_init((unsigned long)p->addr, *probed_mod) &&
+ (*probed_mod)->state != MODULE_STATE_COMING) {
+ module_put(*probed_mod);
+ *probed_mod = NULL;
+ ret = -ENOENT;
}
- /* ret will be updated by following code */
}
+out:
preempt_enable();
jump_label_unlock();
+ return ret;
+}
+
+int __kprobes register_kprobe(struct kprobe *p)
+{
+ int ret;
+ struct kprobe *old_p;
+ struct module *probed_mod;
+ kprobe_opcode_t *addr;
+
+ /* Adjust probe address from symbol */
+ addr = kprobe_addr(p);
+ if (IS_ERR(addr))
+ return PTR_ERR(addr);
+ p->addr = addr;
+
+ ret = check_kprobe_rereg(p);
+ if (ret)
+ return ret;
+
+ /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
+ p->flags &= KPROBE_FLAG_DISABLED;
p->nmissed = 0;
INIT_LIST_HEAD(&p->list);
- mutex_lock(&kprobe_mutex);
- jump_label_lock(); /* needed to call jump_label_text_reserved() */
+ ret = check_kprobe_address_safe(p, &probed_mod);
+ if (ret)
+ return ret;
- get_online_cpus(); /* For avoiding text_mutex deadlock. */
- mutex_lock(&text_mutex);
+ mutex_lock(&kprobe_mutex);
old_p = get_kprobe(p->addr);
if (old_p) {
goto out;
}
- ret = arch_prepare_kprobe(p);
+ mutex_lock(&text_mutex); /* Avoiding text modification */
+ ret = prepare_kprobe(p);
+ mutex_unlock(&text_mutex);
if (ret)
goto out;
&kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
if (!kprobes_all_disarmed && !kprobe_disabled(p))
- __arm_kprobe(p);
+ arm_kprobe(p);
/* Try to optimize kprobe */
try_to_optimize_kprobe(p);
out:
- mutex_unlock(&text_mutex);
- put_online_cpus();
- jump_label_unlock();
mutex_unlock(&kprobe_mutex);
if (probed_mod)
module_put(probed_mod);
return ret;
-
-cannot_probe:
- preempt_enable();
- jump_label_unlock();
- return ret;
}
EXPORT_SYMBOL_GPL(register_kprobe);
/* Try to disarm and disable this/parent probe */
if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
- disarm_kprobe(orig_p);
+ disarm_kprobe(orig_p, true);
orig_p->flags |= KPROBE_FLAG_DISABLED;
}
}
if (!pp)
pp = p;
- seq_printf(pi, "%s%s%s\n",
+ seq_printf(pi, "%s%s%s%s\n",
(kprobe_gone(p) ? "[GONE]" : ""),
((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
- (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""));
+ (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""),
+ (kprobe_ftrace(pp) ? "[FTRACE]" : ""));
}
static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
goto already_enabled;
/* Arming kprobes doesn't optimize kprobe itself */
- 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))
- __arm_kprobe(p);
+ arm_kprobe(p);
}
- mutex_unlock(&text_mutex);
kprobes_all_disarmed = false;
printk(KERN_INFO "Kprobes globally enabled\n");
kprobes_all_disarmed = true;
printk(KERN_INFO "Kprobes globally disabled\n");
- 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, false);
+ disarm_kprobe(p, false);
}
}
- mutex_unlock(&text_mutex);
mutex_unlock(&kprobe_mutex);
/* Wait for disarming all kprobes by optimizer */
projects / cascardo / linux.git / blobdiff