diff options
Diffstat (limited to 'tools/testing/selftests/bpf/progs/refcounted_kptr.c')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/refcounted_kptr.c | 571 |
1 files changed, 571 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/refcounted_kptr.c b/tools/testing/selftests/bpf/progs/refcounted_kptr.c new file mode 100644 index 000000000000..893a4fdb4b6e --- /dev/null +++ b/tools/testing/selftests/bpf/progs/refcounted_kptr.c @@ -0,0 +1,571 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */ + +#include <vmlinux.h> +#include <bpf/bpf_tracing.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_core_read.h> +#include "bpf_misc.h" +#include "bpf_experimental.h" + +extern void bpf_rcu_read_lock(void) __ksym; +extern void bpf_rcu_read_unlock(void) __ksym; + +struct node_data { + long key; + long list_data; + struct bpf_rb_node r; + struct bpf_list_node l; + struct bpf_refcount ref; +}; + +struct map_value { + struct node_data __kptr *node; +}; + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, struct map_value); + __uint(max_entries, 2); +} stashed_nodes SEC(".maps"); + +struct node_acquire { + long key; + long data; + struct bpf_rb_node node; + struct bpf_refcount refcount; +}; + +#define private(name) SEC(".bss." #name) __hidden __attribute__((aligned(8))) +private(A) struct bpf_spin_lock lock; +private(A) struct bpf_rb_root root __contains(node_data, r); +private(A) struct bpf_list_head head __contains(node_data, l); + +private(B) struct bpf_spin_lock alock; +private(B) struct bpf_rb_root aroot __contains(node_acquire, node); + +private(C) struct bpf_spin_lock block; +private(C) struct bpf_rb_root broot __contains(node_data, r); + +static bool less(struct bpf_rb_node *node_a, const struct bpf_rb_node *node_b) +{ + struct node_data *a; + struct node_data *b; + + a = container_of(node_a, struct node_data, r); + b = container_of(node_b, struct node_data, r); + + return a->key < b->key; +} + +static bool less_a(struct bpf_rb_node *a, const struct bpf_rb_node *b) +{ + struct node_acquire *node_a; + struct node_acquire *node_b; + + node_a = container_of(a, struct node_acquire, node); + node_b = container_of(b, struct node_acquire, node); + + return node_a->key < node_b->key; +} + +static long __insert_in_tree_and_list(struct bpf_list_head *head, + struct bpf_rb_root *root, + struct bpf_spin_lock *lock) +{ + struct node_data *n, *m; + + n = bpf_obj_new(typeof(*n)); + if (!n) + return -1; + + m = bpf_refcount_acquire(n); + m->key = 123; + m->list_data = 456; + + bpf_spin_lock(lock); + if (bpf_rbtree_add(root, &n->r, less)) { + /* Failure to insert - unexpected */ + bpf_spin_unlock(lock); + bpf_obj_drop(m); + return -2; + } + bpf_spin_unlock(lock); + + bpf_spin_lock(lock); + if (bpf_list_push_front(head, &m->l)) { + /* Failure to insert - unexpected */ + bpf_spin_unlock(lock); + return -3; + } + bpf_spin_unlock(lock); + return 0; +} + +static long __stash_map_insert_tree(int idx, int val, struct bpf_rb_root *root, + struct bpf_spin_lock *lock) +{ + struct map_value *mapval; + struct node_data *n, *m; + + mapval = bpf_map_lookup_elem(&stashed_nodes, &idx); + if (!mapval) + return -1; + + n = bpf_obj_new(typeof(*n)); + if (!n) + return -2; + + n->key = val; + m = bpf_refcount_acquire(n); + + n = bpf_kptr_xchg(&mapval->node, n); + if (n) { + bpf_obj_drop(n); + bpf_obj_drop(m); + return -3; + } + + bpf_spin_lock(lock); + if (bpf_rbtree_add(root, &m->r, less)) { + /* Failure to insert - unexpected */ + bpf_spin_unlock(lock); + return -4; + } + bpf_spin_unlock(lock); + return 0; +} + +static long __read_from_tree(struct bpf_rb_root *root, + struct bpf_spin_lock *lock, + bool remove_from_tree) +{ + struct bpf_rb_node *rb; + struct node_data *n; + long res = -99; + + bpf_spin_lock(lock); + + rb = bpf_rbtree_first(root); + if (!rb) { + bpf_spin_unlock(lock); + return -1; + } + + n = container_of(rb, struct node_data, r); + res = n->key; + + if (!remove_from_tree) { + bpf_spin_unlock(lock); + return res; + } + + rb = bpf_rbtree_remove(root, rb); + bpf_spin_unlock(lock); + if (!rb) + return -2; + n = container_of(rb, struct node_data, r); + bpf_obj_drop(n); + return res; +} + +static long __read_from_list(struct bpf_list_head *head, + struct bpf_spin_lock *lock, + bool remove_from_list) +{ + struct bpf_list_node *l; + struct node_data *n; + long res = -99; + + bpf_spin_lock(lock); + + l = bpf_list_pop_front(head); + if (!l) { + bpf_spin_unlock(lock); + return -1; + } + + n = container_of(l, struct node_data, l); + res = n->list_data; + + if (!remove_from_list) { + if (bpf_list_push_back(head, &n->l)) { + bpf_spin_unlock(lock); + return -2; + } + } + + bpf_spin_unlock(lock); + + if (remove_from_list) + bpf_obj_drop(n); + return res; +} + +static long __read_from_unstash(int idx) +{ + struct node_data *n = NULL; + struct map_value *mapval; + long val = -99; + + mapval = bpf_map_lookup_elem(&stashed_nodes, &idx); + if (!mapval) + return -1; + + n = bpf_kptr_xchg(&mapval->node, n); + if (!n) + return -2; + + val = n->key; + bpf_obj_drop(n); + return val; +} + +#define INSERT_READ_BOTH(rem_tree, rem_list, desc) \ +SEC("tc") \ +__description(desc) \ +__success __retval(579) \ +long insert_and_remove_tree_##rem_tree##_list_##rem_list(void *ctx) \ +{ \ + long err, tree_data, list_data; \ + \ + err = __insert_in_tree_and_list(&head, &root, &lock); \ + if (err) \ + return err; \ + \ + err = __read_from_tree(&root, &lock, rem_tree); \ + if (err < 0) \ + return err; \ + else \ + tree_data = err; \ + \ + err = __read_from_list(&head, &lock, rem_list); \ + if (err < 0) \ + return err; \ + else \ + list_data = err; \ + \ + return tree_data + list_data; \ +} + +/* After successful insert of struct node_data into both collections: + * - it should have refcount = 2 + * - removing / not removing the node_data from a collection after + * reading should have no effect on ability to read / remove from + * the other collection + */ +INSERT_READ_BOTH(true, true, "insert_read_both: remove from tree + list"); +INSERT_READ_BOTH(false, false, "insert_read_both: remove from neither"); +INSERT_READ_BOTH(true, false, "insert_read_both: remove from tree"); +INSERT_READ_BOTH(false, true, "insert_read_both: remove from list"); + +#undef INSERT_READ_BOTH +#define INSERT_READ_BOTH(rem_tree, rem_list, desc) \ +SEC("tc") \ +__description(desc) \ +__success __retval(579) \ +long insert_and_remove_lf_tree_##rem_tree##_list_##rem_list(void *ctx) \ +{ \ + long err, tree_data, list_data; \ + \ + err = __insert_in_tree_and_list(&head, &root, &lock); \ + if (err) \ + return err; \ + \ + err = __read_from_list(&head, &lock, rem_list); \ + if (err < 0) \ + return err; \ + else \ + list_data = err; \ + \ + err = __read_from_tree(&root, &lock, rem_tree); \ + if (err < 0) \ + return err; \ + else \ + tree_data = err; \ + \ + return tree_data + list_data; \ +} + +/* Similar to insert_read_both, but list data is read and possibly removed + * first + * + * Results should be no different than reading and possibly removing rbtree + * node first + */ +INSERT_READ_BOTH(true, true, "insert_read_both_list_first: remove from tree + list"); +INSERT_READ_BOTH(false, false, "insert_read_both_list_first: remove from neither"); +INSERT_READ_BOTH(true, false, "insert_read_both_list_first: remove from tree"); +INSERT_READ_BOTH(false, true, "insert_read_both_list_first: remove from list"); + +#define INSERT_DOUBLE_READ_AND_DEL(read_fn, read_root, desc) \ +SEC("tc") \ +__description(desc) \ +__success __retval(-1) \ +long insert_double_##read_fn##_and_del_##read_root(void *ctx) \ +{ \ + long err, list_data; \ + \ + err = __insert_in_tree_and_list(&head, &root, &lock); \ + if (err) \ + return err; \ + \ + err = read_fn(&read_root, &lock, true); \ + if (err < 0) \ + return err; \ + else \ + list_data = err; \ + \ + err = read_fn(&read_root, &lock, true); \ + if (err < 0) \ + return err; \ + \ + return err + list_data; \ +} + +/* Insert into both tree and list, then try reading-and-removing from either twice + * + * The second read-and-remove should fail on read step since the node has + * already been removed + */ +INSERT_DOUBLE_READ_AND_DEL(__read_from_tree, root, "insert_double_del: 2x read-and-del from tree"); +INSERT_DOUBLE_READ_AND_DEL(__read_from_list, head, "insert_double_del: 2x read-and-del from list"); + +#define INSERT_STASH_READ(rem_tree, desc) \ +SEC("tc") \ +__description(desc) \ +__success __retval(84) \ +long insert_rbtree_and_stash__del_tree_##rem_tree(void *ctx) \ +{ \ + long err, tree_data, map_data; \ + \ + err = __stash_map_insert_tree(0, 42, &root, &lock); \ + if (err) \ + return err; \ + \ + err = __read_from_tree(&root, &lock, rem_tree); \ + if (err < 0) \ + return err; \ + else \ + tree_data = err; \ + \ + err = __read_from_unstash(0); \ + if (err < 0) \ + return err; \ + else \ + map_data = err; \ + \ + return tree_data + map_data; \ +} + +/* Stash a refcounted node in map_val, insert same node into tree, then try + * reading data from tree then unstashed map_val, possibly removing from tree + * + * Removing from tree should have no effect on map_val kptr validity + */ +INSERT_STASH_READ(true, "insert_stash_read: remove from tree"); +INSERT_STASH_READ(false, "insert_stash_read: don't remove from tree"); + +SEC("tc") +__success +long rbtree_refcounted_node_ref_escapes(void *ctx) +{ + struct node_acquire *n, *m; + + n = bpf_obj_new(typeof(*n)); + if (!n) + return 1; + + bpf_spin_lock(&alock); + bpf_rbtree_add(&aroot, &n->node, less_a); + m = bpf_refcount_acquire(n); + bpf_spin_unlock(&alock); + if (!m) + return 2; + + m->key = 2; + bpf_obj_drop(m); + return 0; +} + +SEC("tc") +__success +long rbtree_refcounted_node_ref_escapes_owning_input(void *ctx) +{ + struct node_acquire *n, *m; + + n = bpf_obj_new(typeof(*n)); + if (!n) + return 1; + + m = bpf_refcount_acquire(n); + m->key = 2; + + bpf_spin_lock(&alock); + bpf_rbtree_add(&aroot, &n->node, less_a); + bpf_spin_unlock(&alock); + + bpf_obj_drop(m); + + return 0; +} + +static long __stash_map_empty_xchg(struct node_data *n, int idx) +{ + struct map_value *mapval = bpf_map_lookup_elem(&stashed_nodes, &idx); + + if (!mapval) { + bpf_obj_drop(n); + return 1; + } + n = bpf_kptr_xchg(&mapval->node, n); + if (n) { + bpf_obj_drop(n); + return 2; + } + return 0; +} + +SEC("tc") +long rbtree_wrong_owner_remove_fail_a1(void *ctx) +{ + struct node_data *n, *m; + + n = bpf_obj_new(typeof(*n)); + if (!n) + return 1; + m = bpf_refcount_acquire(n); + + if (__stash_map_empty_xchg(n, 0)) { + bpf_obj_drop(m); + return 2; + } + + if (__stash_map_empty_xchg(m, 1)) + return 3; + + return 0; +} + +SEC("tc") +long rbtree_wrong_owner_remove_fail_b(void *ctx) +{ + struct map_value *mapval; + struct node_data *n; + int idx = 0; + + mapval = bpf_map_lookup_elem(&stashed_nodes, &idx); + if (!mapval) + return 1; + + n = bpf_kptr_xchg(&mapval->node, NULL); + if (!n) + return 2; + + bpf_spin_lock(&block); + + bpf_rbtree_add(&broot, &n->r, less); + + bpf_spin_unlock(&block); + return 0; +} + +SEC("tc") +long rbtree_wrong_owner_remove_fail_a2(void *ctx) +{ + struct map_value *mapval; + struct bpf_rb_node *res; + struct node_data *m; + int idx = 1; + + mapval = bpf_map_lookup_elem(&stashed_nodes, &idx); + if (!mapval) + return 1; + + m = bpf_kptr_xchg(&mapval->node, NULL); + if (!m) + return 2; + bpf_spin_lock(&lock); + + /* make m non-owning ref */ + bpf_list_push_back(&head, &m->l); + res = bpf_rbtree_remove(&root, &m->r); + + bpf_spin_unlock(&lock); + if (res) { + bpf_obj_drop(container_of(res, struct node_data, r)); + return 3; + } + return 0; +} + +SEC("?fentry.s/bpf_testmod_test_read") +__success +int BPF_PROG(rbtree_sleepable_rcu, + struct file *file, struct kobject *kobj, + struct bin_attribute *bin_attr, char *buf, loff_t off, size_t len) +{ + struct bpf_rb_node *rb; + struct node_data *n, *m = NULL; + + n = bpf_obj_new(typeof(*n)); + if (!n) + return 0; + + bpf_rcu_read_lock(); + bpf_spin_lock(&lock); + bpf_rbtree_add(&root, &n->r, less); + rb = bpf_rbtree_first(&root); + if (!rb) + goto err_out; + + rb = bpf_rbtree_remove(&root, rb); + if (!rb) + goto err_out; + + m = container_of(rb, struct node_data, r); + +err_out: + bpf_spin_unlock(&lock); + bpf_rcu_read_unlock(); + if (m) + bpf_obj_drop(m); + return 0; +} + +SEC("?fentry.s/bpf_testmod_test_read") +__success +int BPF_PROG(rbtree_sleepable_rcu_no_explicit_rcu_lock, + struct file *file, struct kobject *kobj, + struct bin_attribute *bin_attr, char *buf, loff_t off, size_t len) +{ + struct bpf_rb_node *rb; + struct node_data *n, *m = NULL; + + n = bpf_obj_new(typeof(*n)); + if (!n) + return 0; + + /* No explicit bpf_rcu_read_lock */ + bpf_spin_lock(&lock); + bpf_rbtree_add(&root, &n->r, less); + rb = bpf_rbtree_first(&root); + if (!rb) + goto err_out; + + rb = bpf_rbtree_remove(&root, rb); + if (!rb) + goto err_out; + + m = container_of(rb, struct node_data, r); + +err_out: + bpf_spin_unlock(&lock); + /* No explicit bpf_rcu_read_unlock */ + if (m) + bpf_obj_drop(m); + return 0; +} + +char _license[] SEC("license") = "GPL"; |