kprobes: Use non RCU traversal APIs on kprobe_tables if possible

[mirror_ubuntu-jammy-kernel.git] / kernel / kprobes.c

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 8b2fd4145ab320cb98d3683ae32bee15d19e8d63..ceb0e273bd699b0535c479508f5cde77cf522b73 100644 (file)
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -46,6 +46,11 @@
 
 
 static int kprobes_initialized;
+/* kprobe_table can be accessed by
+ * - Normal hlist traversal and RCU add/del under kprobe_mutex is held.
+ * Or
+ * - RCU hlist traversal under disabling preempt (breakpoint handlers)
+ */
 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
 
@@ -850,7 +855,7 @@ static void optimize_all_kprobes(void)
        kprobes_allow_optimization = true;
        for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
                head = &kprobe_table[i];
-               hlist_for_each_entry_rcu(p, head, hlist)
+               hlist_for_each_entry(p, head, hlist)
                        if (!kprobe_disabled(p))
                                optimize_kprobe(p);
        }
@@ -877,7 +882,7 @@ static void unoptimize_all_kprobes(void)
        kprobes_allow_optimization = false;
        for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
                head = &kprobe_table[i];
-               hlist_for_each_entry_rcu(p, head, hlist) {
+               hlist_for_each_entry(p, head, hlist) {
                        if (!kprobe_disabled(p))
                                unoptimize_kprobe(p, false);
                }
@@ -1500,12 +1505,14 @@ static struct kprobe *__get_valid_kprobe(struct kprobe *p)
 {
        struct kprobe *ap, *list_p;
 
+       lockdep_assert_held(&kprobe_mutex);
+
        ap = get_kprobe(p->addr);
        if (unlikely(!ap))
                return NULL;
 
        if (p != ap) {
-               list_for_each_entry_rcu(list_p, &ap->list, list)
+               list_for_each_entry(list_p, &ap->list, list)
                        if (list_p == p)
                        /* kprobe p is a valid probe */
                                goto valid;
@@ -1670,7 +1677,9 @@ static int aggr_kprobe_disabled(struct kprobe *ap)
 {
        struct kprobe *kp;
 
-       list_for_each_entry_rcu(kp, &ap->list, list)
+       lockdep_assert_held(&kprobe_mutex);
+
+       list_for_each_entry(kp, &ap->list, list)
                if (!kprobe_disabled(kp))
                        /*
                         * There is an active probe on the list.
@@ -1749,7 +1758,7 @@ static int __unregister_kprobe_top(struct kprobe *p)
        else {
                /* If disabling probe has special handlers, update aggrprobe */
                if (p->post_handler && !kprobe_gone(p)) {
-                       list_for_each_entry_rcu(list_p, &ap->list, list) {
+                       list_for_each_entry(list_p, &ap->list, list) {
                                if ((list_p != p) && (list_p->post_handler))
                                        goto noclean;
                        }
@@ -2063,13 +2072,15 @@ static void kill_kprobe(struct kprobe *p)
 {
        struct kprobe *kp;
 
+       lockdep_assert_held(&kprobe_mutex);
+
        p->flags |= KPROBE_FLAG_GONE;
        if (kprobe_aggrprobe(p)) {
                /*
                 * If this is an aggr_kprobe, we have to list all the
                 * chained probes and mark them GONE.
                 */
-               list_for_each_entry_rcu(kp, &p->list, list)
+               list_for_each_entry(kp, &p->list, list)
                        kp->flags |= KPROBE_FLAG_GONE;
                p->post_handler = NULL;
                kill_optimized_kprobe(p);
@@ -2313,7 +2324,7 @@ static int kprobes_module_callback(struct notifier_block *nb,
        mutex_lock(&kprobe_mutex);
        for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
                head = &kprobe_table[i];
-               hlist_for_each_entry_rcu(p, head, hlist)
+               hlist_for_each_entry(p, head, hlist)
                        if (within_module_init((unsigned long)p->addr, mod) ||
                            (checkcore &&
                             within_module_core((unsigned long)p->addr, mod))) {
@@ -2551,7 +2562,7 @@ static int arm_all_kprobes(void)
        for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
                head = &kprobe_table[i];
                /* Arm all kprobes on a best-effort basis */
-               hlist_for_each_entry_rcu(p, head, hlist) {
+               hlist_for_each_entry(p, head, hlist) {
                        if (!kprobe_disabled(p)) {
                                err = arm_kprobe(p);
                                if (err)  {
@@ -2594,7 +2605,7 @@ static int disarm_all_kprobes(void)
        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) {
+               hlist_for_each_entry(p, head, hlist) {
                        if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) {
                                err = disarm_kprobe(p, false);
                                if (err) {