In trace_remote_register(), if registration of events or the init callback fails, the created tracefs and eventfs directories are leaked.
Release the entire eventfs and tracefs hierarchy on trace_remote registration. Signed-off-by: Vincent Donnefort <[email protected]> diff --git a/kernel/trace/trace_remote.c b/kernel/trace/trace_remote.c index d6c3f94d67cd..cfe84e9b8fe6 100644 --- a/kernel/trace/trace_remote.c +++ b/kernel/trace/trace_remote.c @@ -44,7 +44,8 @@ struct trace_remote { struct trace_buffer *trace_buffer; struct trace_buffer_desc *trace_buffer_desc; struct dentry *dentry; - struct eventfs_inode *eventfs; + struct eventfs_inode *eventfs_root; + struct eventfs_inode *eventfs_subdir; struct remote_event *events; unsigned long nr_events; unsigned long trace_buffer_size; @@ -795,26 +796,28 @@ static const struct file_operations trace_fops = { .release = trace_release, }; +static struct dentry *tracefs_root; +static DEFINE_MUTEX(tracefs_lock); +static u64 tracefs_root_count; + static int trace_remote_init_tracefs(const char *name, struct trace_remote *remote) { struct dentry *remote_d, *percpu_d, *d; - static struct dentry *root; - static DEFINE_MUTEX(lock); bool root_inited = false; int cpu; - guard(mutex)(&lock); + guard(mutex)(&tracefs_lock); - if (!root) { - root = tracefs_create_dir(TRACEFS_DIR, NULL); - if (!root) { + if (!tracefs_root) { + tracefs_root = tracefs_create_dir(TRACEFS_DIR, NULL); + if (!tracefs_root) { pr_err("Failed to create tracefs dir "TRACEFS_DIR"\n"); return -ENOMEM; } root_inited = true; } - remote_d = tracefs_create_dir(name, root); + remote_d = tracefs_create_dir(name, tracefs_root); if (!remote_d) { pr_err("Failed to create tracefs dir "TRACEFS_DIR"%s/\n", name); goto err; @@ -866,14 +869,15 @@ static int trace_remote_init_tracefs(const char *name, struct trace_remote *remo goto err; } + tracefs_root_count++; remote->dentry = remote_d; return 0; err: if (root_inited) { - tracefs_remove(root); - root = NULL; + tracefs_remove(tracefs_root); + tracefs_root = NULL; } else { tracefs_remove(remote_d); } @@ -881,8 +885,26 @@ static int trace_remote_init_tracefs(const char *name, struct trace_remote *remo return -ENOMEM; } +static void trace_remote_remove_tracefs(struct trace_remote *remote) +{ + guard(mutex)(&tracefs_lock); + + if (!remote->dentry) + return; + + tracefs_remove(remote->dentry); + remote->dentry = NULL; + + tracefs_root_count--; + if (!tracefs_root_count) { + tracefs_remove(tracefs_root); + tracefs_root = NULL; + } +} + static int trace_remote_register_events(const char *remote_name, struct trace_remote *remote, struct remote_event *events, size_t nr_events); +static void trace_remote_unregister_events(struct trace_remote *remote); /** * trace_remote_register() - Register a Tracefs remote @@ -905,10 +927,9 @@ static int trace_remote_register_events(const char *remote_name, struct trace_re int trace_remote_register(const char *name, struct trace_remote_callbacks *cbs, void *priv, struct remote_event *events, size_t nr_events) { - struct trace_remote *remote; + struct trace_remote *remote __free(kfree) = kzalloc_obj(*remote); int ret; - remote = kzalloc_obj(*remote); if (!remote) return -ENOMEM; @@ -919,22 +940,30 @@ int trace_remote_register(const char *name, struct trace_remote_callbacks *cbs, mutex_init(&remote->lock); init_rwsem(&remote->reader_lock); - if (trace_remote_init_tracefs(name, remote)) { - kfree(remote); - return -ENOMEM; - } + ret = trace_remote_init_tracefs(name, remote); + if (ret) + return ret; ret = trace_remote_register_events(name, remote, events, nr_events); if (ret) { pr_err("Failed to register events for trace remote '%s' (%d)\n", name, ret); - return ret; + goto err_remove_tracefs; } ret = cbs->init ? cbs->init(remote->dentry, priv) : 0; - if (ret) + if (ret) { pr_err("Init failed for trace remote '%s' (%d)\n", name, ret); + goto err_unregister_events; + } + + no_free_ptr(remote); + return 0; +err_unregister_events: + trace_remote_unregister_events(remote); +err_remove_tracefs: + trace_remote_remove_tracefs(remote); return ret; } EXPORT_SYMBOL_GPL(trace_remote_register); @@ -1267,7 +1296,6 @@ static int remote_events_dir_callback(const char *name, umode_t *mode, void **da static int trace_remote_init_eventfs(const char *remote_name, struct trace_remote *remote, struct remote_event *evt) { - struct eventfs_inode *eventfs = remote->eventfs; static struct eventfs_entry dir_entries[] = { { .name = "enable", @@ -1292,35 +1320,37 @@ static int trace_remote_init_eventfs(const char *remote_name, struct trace_remot .callback = remote_event_callback, } }; - bool eventfs_create = false; + struct eventfs_inode *eventfs_root, *eventfs_subdir, *e; - if (!eventfs) { - eventfs = eventfs_create_events_dir("events", remote->dentry, dir_entries, - ARRAY_SIZE(dir_entries), remote); - if (IS_ERR(eventfs)) - return PTR_ERR(eventfs); + eventfs_root = remote->eventfs_root; + eventfs_subdir = remote->eventfs_subdir; + if (!eventfs_root) { + eventfs_root = eventfs_create_events_dir("events", remote->dentry, dir_entries, + ARRAY_SIZE(dir_entries), remote); + if (IS_ERR(eventfs_root)) + return PTR_ERR(eventfs_root); /* * Create similar hierarchy as local events even if a single system is supported at * the moment */ - eventfs = eventfs_create_dir(remote_name, eventfs, NULL, 0, NULL); - if (IS_ERR(eventfs)) - return PTR_ERR(eventfs); - - remote->eventfs = eventfs; - eventfs_create = true; + eventfs_subdir = eventfs_create_dir(remote_name, eventfs_root, NULL, 0, NULL); + if (IS_ERR(eventfs_subdir)) { + eventfs_remove_events_dir(eventfs_root); + return PTR_ERR(eventfs_subdir); + } } - eventfs = eventfs_create_dir(evt->name, eventfs, entries, ARRAY_SIZE(entries), evt); - if (IS_ERR(eventfs)) { - if (eventfs_create) { - eventfs_remove_events_dir(remote->eventfs); - remote->eventfs = NULL; - } - return PTR_ERR(eventfs); + e = eventfs_create_dir(evt->name, eventfs_subdir, entries, ARRAY_SIZE(entries), evt); + if (IS_ERR(e)) { + if (!remote->eventfs_root) + eventfs_remove_events_dir(eventfs_root); + return PTR_ERR(e); } + remote->eventfs_root = eventfs_root; + remote->eventfs_subdir = eventfs_subdir; + return 0; } @@ -1335,11 +1365,11 @@ static int trace_remote_attach_events(struct trace_remote *remote, struct remote if (evt->remote) return -EEXIST; - evt->remote = remote; - /* We need events to be sorted for efficient lookup */ if (i && evt->id <= events[i - 1].id) return -EINVAL; + + evt->remote = remote; } remote->events = events; @@ -1348,14 +1378,33 @@ static int trace_remote_attach_events(struct trace_remote *remote, struct remote return 0; } +static void trace_remote_detach_events(struct trace_remote *remote, struct remote_event *events, + size_t nr_events) +{ + int i; + + for (i = 0; i < nr_events; i++) { + struct remote_event *evt = &events[i]; + + if (evt->remote == remote) + evt->remote = NULL; + } + + remote->events = NULL; + remote->nr_events = 0; +} + static int trace_remote_register_events(const char *remote_name, struct trace_remote *remote, struct remote_event *events, size_t nr_events) { int i, ret; ret = trace_remote_attach_events(remote, events, nr_events); - if (ret) + if (ret) { + /* It is safe to call detach on a half-registered array */ + trace_remote_detach_events(remote, events, nr_events); return ret; + } for (i = 0; i < nr_events; i++) { struct remote_event *evt = &events[i]; @@ -1369,6 +1418,12 @@ static int trace_remote_register_events(const char *remote_name, struct trace_re return 0; } +static void trace_remote_unregister_events(struct trace_remote *remote) +{ + trace_remote_detach_events(remote, remote->events, remote->nr_events); + eventfs_remove_events_dir(remote->eventfs_root); +} + static int __cmp_events(const void *key, const void *data) { const struct remote_event *evt = data; -- 2.54.0.1032.g2f8565e1d1-goog
