diff options
| -rw-r--r-- | kernel/trace/fprobe.c | 103 |
1 files changed, 101 insertions, 2 deletions
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c index cb86f90d4b1e..95c6e3473a76 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -89,8 +89,11 @@ static bool delete_fprobe_node(struct fprobe_hlist_node *node) { lockdep_assert_held(&fprobe_mutex); - WRITE_ONCE(node->fp, NULL); - hlist_del_rcu(&node->hlist); + /* Avoid double deleting */ + if (READ_ONCE(node->fp) != NULL) { + WRITE_ONCE(node->fp, NULL); + hlist_del_rcu(&node->hlist); + } return !!find_first_fprobe_node(node->addr); } @@ -411,6 +414,102 @@ static void fprobe_graph_remove_ips(unsigned long *addrs, int num) ftrace_set_filter_ips(&fprobe_graph_ops.ops, addrs, num, 1, 0); } +#ifdef CONFIG_MODULES + +#define FPROBE_IPS_BATCH_INIT 8 +/* instruction pointer address list */ +struct fprobe_addr_list { + int index; + int size; + unsigned long *addrs; +}; + +static int fprobe_addr_list_add(struct fprobe_addr_list *alist, unsigned long addr) +{ + unsigned long *addrs; + + if (alist->index >= alist->size) + return -ENOMEM; + + alist->addrs[alist->index++] = addr; + if (alist->index < alist->size) + return 0; + + /* Expand the address list */ + addrs = kcalloc(alist->size * 2, sizeof(*addrs), GFP_KERNEL); + if (!addrs) + return -ENOMEM; + + memcpy(addrs, alist->addrs, alist->size * sizeof(*addrs)); + alist->size *= 2; + kfree(alist->addrs); + alist->addrs = addrs; + + return 0; +} + +static void fprobe_remove_node_in_module(struct module *mod, struct hlist_head *head, + struct fprobe_addr_list *alist) +{ + struct fprobe_hlist_node *node; + int ret = 0; + + hlist_for_each_entry_rcu(node, head, hlist) { + if (!within_module(node->addr, mod)) + continue; + if (delete_fprobe_node(node)) + continue; + /* + * If failed to update alist, just continue to update hlist. + * Therefore, at list user handler will not hit anymore. + */ + if (!ret) + ret = fprobe_addr_list_add(alist, node->addr); + } +} + +/* Handle module unloading to manage fprobe_ip_table. */ +static int fprobe_module_callback(struct notifier_block *nb, + unsigned long val, void *data) +{ + struct fprobe_addr_list alist = {.size = FPROBE_IPS_BATCH_INIT}; + struct module *mod = data; + int i; + + if (val != MODULE_STATE_GOING) + return NOTIFY_DONE; + + alist.addrs = kcalloc(alist.size, sizeof(*alist.addrs), GFP_KERNEL); + /* If failed to alloc memory, we can not remove ips from hash. */ + if (!alist.addrs) + return NOTIFY_DONE; + + mutex_lock(&fprobe_mutex); + for (i = 0; i < FPROBE_IP_TABLE_SIZE; i++) + fprobe_remove_node_in_module(mod, &fprobe_ip_table[i], &alist); + + if (alist.index < alist.size && alist.index > 0) + ftrace_set_filter_ips(&fprobe_graph_ops.ops, + alist.addrs, alist.index, 1, 0); + mutex_unlock(&fprobe_mutex); + + kfree(alist.addrs); + + return NOTIFY_DONE; +} + +static struct notifier_block fprobe_module_nb = { + .notifier_call = fprobe_module_callback, + .priority = 0, +}; + +static int __init init_fprobe_module(void) +{ + return register_module_notifier(&fprobe_module_nb); +} +early_initcall(init_fprobe_module); +#endif + static int symbols_cmp(const void *a, const void *b) { const char **str_a = (const char **) a; |