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-rw-r--r--kernel/kprobes.c178
1 files changed, 128 insertions, 50 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index da2ccf142358..102160ff5c66 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -978,67 +978,90 @@ static int prepare_kprobe(struct kprobe *p)
}
/* Caller must lock kprobe_mutex */
-static void arm_kprobe_ftrace(struct kprobe *p)
+static int arm_kprobe_ftrace(struct kprobe *p)
{
- int ret;
+ int ret = 0;
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) {
+ if (ret) {
+ pr_debug("Failed to arm kprobe-ftrace at %p (%d)\n", p->addr, ret);
+ return ret;
+ }
+
+ if (kprobe_ftrace_enabled == 0) {
ret = register_ftrace_function(&kprobe_ftrace_ops);
- WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret);
+ if (ret) {
+ pr_debug("Failed to init kprobe-ftrace (%d)\n", ret);
+ goto err_ftrace;
+ }
}
+
+ kprobe_ftrace_enabled++;
+ return ret;
+
+err_ftrace:
+ /*
+ * Note: Since kprobe_ftrace_ops has IPMODIFY set, and ftrace requires a
+ * non-empty filter_hash for IPMODIFY ops, we're safe from an accidental
+ * empty filter_hash which would undesirably trace all functions.
+ */
+ ftrace_set_filter_ip(&kprobe_ftrace_ops, (unsigned long)p->addr, 1, 0);
+ return ret;
}
/* Caller must lock kprobe_mutex */
-static void disarm_kprobe_ftrace(struct kprobe *p)
+static int disarm_kprobe_ftrace(struct kprobe *p)
{
- int ret;
+ int ret = 0;
- kprobe_ftrace_enabled--;
- if (kprobe_ftrace_enabled == 0) {
+ if (kprobe_ftrace_enabled == 1) {
ret = unregister_ftrace_function(&kprobe_ftrace_ops);
- WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret);
+ if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (%d)\n", ret))
+ return ret;
}
+
+ kprobe_ftrace_enabled--;
+
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);
+ return ret;
}
#else /* !CONFIG_KPROBES_ON_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)
+#define arm_kprobe_ftrace(p) (-ENODEV)
+#define disarm_kprobe_ftrace(p) (-ENODEV)
#endif
/* Arm a kprobe with text_mutex */
-static void arm_kprobe(struct kprobe *kp)
+static int arm_kprobe(struct kprobe *kp)
{
- if (unlikely(kprobe_ftrace(kp))) {
- arm_kprobe_ftrace(kp);
- return;
- }
+ if (unlikely(kprobe_ftrace(kp)))
+ return arm_kprobe_ftrace(kp);
+
cpus_read_lock();
mutex_lock(&text_mutex);
__arm_kprobe(kp);
mutex_unlock(&text_mutex);
cpus_read_unlock();
+
+ return 0;
}
/* Disarm a kprobe with text_mutex */
-static void disarm_kprobe(struct kprobe *kp, bool reopt)
+static int disarm_kprobe(struct kprobe *kp, bool reopt)
{
- if (unlikely(kprobe_ftrace(kp))) {
- disarm_kprobe_ftrace(kp);
- return;
- }
+ if (unlikely(kprobe_ftrace(kp)))
+ return disarm_kprobe_ftrace(kp);
cpus_read_lock();
mutex_lock(&text_mutex);
__disarm_kprobe(kp, reopt);
mutex_unlock(&text_mutex);
cpus_read_unlock();
+
+ return 0;
}
/*
@@ -1362,9 +1385,15 @@ out:
if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) {
ap->flags &= ~KPROBE_FLAG_DISABLED;
- if (!kprobes_all_disarmed)
+ if (!kprobes_all_disarmed) {
/* Arm the breakpoint again. */
- arm_kprobe(ap);
+ ret = arm_kprobe(ap);
+ if (ret) {
+ ap->flags |= KPROBE_FLAG_DISABLED;
+ list_del_rcu(&p->list);
+ synchronize_sched();
+ }
+ }
}
return ret;
}
@@ -1573,8 +1602,14 @@ int register_kprobe(struct kprobe *p)
hlist_add_head_rcu(&p->hlist,
&kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
- if (!kprobes_all_disarmed && !kprobe_disabled(p))
- arm_kprobe(p);
+ if (!kprobes_all_disarmed && !kprobe_disabled(p)) {
+ ret = arm_kprobe(p);
+ if (ret) {
+ hlist_del_rcu(&p->hlist);
+ synchronize_sched();
+ goto out;
+ }
+ }
/* Try to optimize kprobe */
try_to_optimize_kprobe(p);
@@ -1608,11 +1643,12 @@ static int aggr_kprobe_disabled(struct kprobe *ap)
static struct kprobe *__disable_kprobe(struct kprobe *p)
{
struct kprobe *orig_p;
+ int ret;
/* Get an original kprobe for return */
orig_p = __get_valid_kprobe(p);
if (unlikely(orig_p == NULL))
- return NULL;
+ return ERR_PTR(-EINVAL);
if (!kprobe_disabled(p)) {
/* Disable probe if it is a child probe */
@@ -1626,8 +1662,13 @@ static struct kprobe *__disable_kprobe(struct kprobe *p)
* should have already been disarmed, so
* skip unneed disarming process.
*/
- if (!kprobes_all_disarmed)
- disarm_kprobe(orig_p, true);
+ if (!kprobes_all_disarmed) {
+ ret = disarm_kprobe(orig_p, true);
+ if (ret) {
+ p->flags &= ~KPROBE_FLAG_DISABLED;
+ return ERR_PTR(ret);
+ }
+ }
orig_p->flags |= KPROBE_FLAG_DISABLED;
}
}
@@ -1644,8 +1685,8 @@ static int __unregister_kprobe_top(struct kprobe *p)
/* Disable kprobe. This will disarm it if needed. */
ap = __disable_kprobe(p);
- if (ap == NULL)
- return -EINVAL;
+ if (IS_ERR(ap))
+ return PTR_ERR(ap);
if (ap == p)
/*
@@ -2078,12 +2119,14 @@ static void kill_kprobe(struct kprobe *p)
int disable_kprobe(struct kprobe *kp)
{
int ret = 0;
+ struct kprobe *p;
mutex_lock(&kprobe_mutex);
/* Disable this kprobe */
- if (__disable_kprobe(kp) == NULL)
- ret = -EINVAL;
+ p = __disable_kprobe(kp);
+ if (IS_ERR(p))
+ ret = PTR_ERR(p);
mutex_unlock(&kprobe_mutex);
return ret;
@@ -2116,7 +2159,9 @@ int enable_kprobe(struct kprobe *kp)
if (!kprobes_all_disarmed && kprobe_disabled(p)) {
p->flags &= ~KPROBE_FLAG_DISABLED;
- arm_kprobe(p);
+ ret = arm_kprobe(p);
+ if (ret)
+ p->flags |= KPROBE_FLAG_DISABLED;
}
out:
mutex_unlock(&kprobe_mutex);
@@ -2407,11 +2452,12 @@ static const struct file_operations debugfs_kprobe_blacklist_ops = {
.release = seq_release,
};
-static void arm_all_kprobes(void)
+static int arm_all_kprobes(void)
{
struct hlist_head *head;
struct kprobe *p;
- unsigned int i;
+ unsigned int i, total = 0, errors = 0;
+ int err, ret = 0;
mutex_lock(&kprobe_mutex);
@@ -2428,46 +2474,74 @@ static void arm_all_kprobes(void)
/* Arming kprobes doesn't optimize kprobe itself */
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
- hlist_for_each_entry_rcu(p, head, hlist)
- if (!kprobe_disabled(p))
- arm_kprobe(p);
+ /* Arm all kprobes on a best-effort basis */
+ hlist_for_each_entry_rcu(p, head, hlist) {
+ if (!kprobe_disabled(p)) {
+ err = arm_kprobe(p);
+ if (err) {
+ errors++;
+ ret = err;
+ }
+ total++;
+ }
+ }
}
- printk(KERN_INFO "Kprobes globally enabled\n");
+ if (errors)
+ pr_warn("Kprobes globally enabled, but failed to arm %d out of %d probes\n",
+ errors, total);
+ else
+ pr_info("Kprobes globally enabled\n");
already_enabled:
mutex_unlock(&kprobe_mutex);
- return;
+ return ret;
}
-static void disarm_all_kprobes(void)
+static int disarm_all_kprobes(void)
{
struct hlist_head *head;
struct kprobe *p;
- unsigned int i;
+ unsigned int i, total = 0, errors = 0;
+ int err, ret = 0;
mutex_lock(&kprobe_mutex);
/* If kprobes are already disarmed, just return */
if (kprobes_all_disarmed) {
mutex_unlock(&kprobe_mutex);
- return;
+ return 0;
}
kprobes_all_disarmed = true;
- printk(KERN_INFO "Kprobes globally disabled\n");
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
+ /* Disarm all kprobes on a best-effort basis */
hlist_for_each_entry_rcu(p, head, hlist) {
- if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
- disarm_kprobe(p, false);
+ if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) {
+ err = disarm_kprobe(p, false);
+ if (err) {
+ errors++;
+ ret = err;
+ }
+ total++;
+ }
}
}
+
+ if (errors)
+ pr_warn("Kprobes globally disabled, but failed to disarm %d out of %d probes\n",
+ errors, total);
+ else
+ pr_info("Kprobes globally disabled\n");
+
mutex_unlock(&kprobe_mutex);
/* Wait for disarming all kprobes by optimizer */
wait_for_kprobe_optimizer();
+
+ return ret;
}
/*
@@ -2494,6 +2568,7 @@ static ssize_t write_enabled_file_bool(struct file *file,
{
char buf[32];
size_t buf_size;
+ int ret = 0;
buf_size = min(count, (sizeof(buf)-1));
if (copy_from_user(buf, user_buf, buf_size))
@@ -2504,17 +2579,20 @@ static ssize_t write_enabled_file_bool(struct file *file,
case 'y':
case 'Y':
case '1':
- arm_all_kprobes();
+ ret = arm_all_kprobes();
break;
case 'n':
case 'N':
case '0':
- disarm_all_kprobes();
+ ret = disarm_all_kprobes();
break;
default:
return -EINVAL;
}
+ if (ret)
+ return ret;
+
return count;
}
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-19 21:29:42 +0300