Currently, there is no convenient way to see the info that the ref_tracking infrastructure collects. Attempt to create a file in debugfs when called from ref_tracker_dir_init().
The file is given the name "class@%px", as having the unmodified address is helpful for debugging. This should be safe since this directory is only accessible by root If debugfs file creation fails, a pr_warn will be isssued. Signed-off-by: Jeff Layton <jlay...@kernel.org> --- include/linux/ref_tracker.h | 23 ++++++++++++++ lib/ref_tracker.c | 73 +++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 94 insertions(+), 2 deletions(-) diff --git a/include/linux/ref_tracker.h b/include/linux/ref_tracker.h index 3968f993db81e95c0d58c81454311841c1b9cd35..dd289fdda12b1a10197912f5796f97002e785aaf 100644 --- a/include/linux/ref_tracker.h +++ b/include/linux/ref_tracker.h @@ -20,12 +20,27 @@ struct ref_tracker_dir { struct list_head list; /* List of active trackers */ struct list_head quarantine; /* List of dead trackers */ const char *class; /* object classname */ +#ifdef CONFIG_DEBUG_FS + struct dentry *dentry; +#endif char name[32]; #endif }; #ifdef CONFIG_REF_TRACKER +#ifdef CONFIG_DEBUG_FS + +void ref_tracker_dir_debugfs(struct ref_tracker_dir *dir); + +#else /* CONFIG_DEBUG_FS */ + +static inline void ref_tracker_dir_debugfs(struct ref_tracker_dir *dir) +{ +} + +#endif /* CONFIG_DEBUG_FS */ + static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir, unsigned int quarantine_count, const char *class, @@ -39,7 +54,11 @@ static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir, refcount_set(&dir->untracked, 1); refcount_set(&dir->no_tracker, 1); dir->class = class; +#ifdef CONFIG_DEBUG_FS + dir->dentry = NULL; +#endif strscpy(dir->name, name, sizeof(dir->name)); + ref_tracker_dir_debugfs(dir); stack_depot_init(); } @@ -68,6 +87,10 @@ static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir, { } +static inline void ref_tracker_dir_debugfs(struct ref_tracker_dir *dir) +{ +} + static inline void ref_tracker_dir_exit(struct ref_tracker_dir *dir) { } diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c index 6e85e7eb347d86775ba38a72dad7159f9ac41ed9..1df12625d80cc7cff65d9f6be89e1dd5c5ffb7f6 100644 --- a/lib/ref_tracker.c +++ b/lib/ref_tracker.c @@ -29,6 +29,14 @@ struct ref_tracker_dir_stats { } stacks[]; }; +#ifdef CONFIG_DEBUG_FS +static void ref_tracker_debugfs_remove(struct ref_tracker_dir *dir); +#else +static inline void ref_tracker_debugfs_remove(struct ref_tracker_dir *dir) +{ +} +#endif + static struct ref_tracker_dir_stats * ref_tracker_get_stats(struct ref_tracker_dir *dir, unsigned int limit) { @@ -184,6 +192,7 @@ void ref_tracker_dir_exit(struct ref_tracker_dir *dir) bool leak = false; dir->dead = true; + ref_tracker_debugfs_remove(dir); spin_lock_irqsave(&dir->lock, flags); list_for_each_entry_safe(tracker, n, &dir->quarantine, head) { list_del(&tracker->head); @@ -311,8 +320,7 @@ static void __ostream_printf pr_ostream_seq(struct ostream *stream, char *fmt, . va_end(args); } -static __maybe_unused int -ref_tracker_dir_seq_print(struct ref_tracker_dir *dir, struct seq_file *seq) +static int ref_tracker_dir_seq_print(struct ref_tracker_dir *dir, struct seq_file *seq) { struct ostream os = { .func = pr_ostream_seq, .prefix = "", @@ -326,6 +334,67 @@ ref_tracker_dir_seq_print(struct ref_tracker_dir *dir, struct seq_file *seq) return os.used; } +static int ref_tracker_debugfs_show(struct seq_file *f, void *v) +{ + struct ref_tracker_dir *dir = f->private; + + return ref_tracker_dir_seq_print(dir, f); +} + +static int ref_tracker_debugfs_open(struct inode *inode, struct file *filp) +{ + struct ref_tracker_dir *dir = inode->i_private; + + return single_open(filp, ref_tracker_debugfs_show, dir); +} + +static const struct file_operations ref_tracker_debugfs_fops = { + .owner = THIS_MODULE, + .open = ref_tracker_debugfs_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +/** + * ref_tracker_dir_debugfs - create debugfs file for ref_tracker_dir + * @dir: ref_tracker_dir to be associated with debugfs file + * + * In most cases, a debugfs file will be created automatically for every + * ref_tracker_dir. If the object was created before debugfs is brought up + * then that may fail. In those cases, it is safe to call this at a later + * time to create the file. + */ +void ref_tracker_dir_debugfs(struct ref_tracker_dir *dir) +{ + char name[NAME_MAX + 1]; + int ret; + + /* No-op if already created */ + if (!IS_ERR_OR_NULL(dir->dentry)) + return; + + ret = snprintf(name, sizeof(name), "%s@%px", dir->class, dir); + name[sizeof(name) - 1] = '\0'; + + if (ret < sizeof(name)) + dir->dentry = debugfs_create_file(name, S_IFREG | 0400, + ref_tracker_debug_dir, dir, + &ref_tracker_debugfs_fops); + else + dir->dentry = ERR_PTR(-ENAMETOOLONG); + + if (IS_ERR(dir->dentry)) + pr_warn("ref_tracker: unable to create debugfs file for %s: %pe\n", + name, dir->dentry); +} +EXPORT_SYMBOL(ref_tracker_dir_debugfs); + +static void ref_tracker_debugfs_remove(struct ref_tracker_dir *dir) +{ + debugfs_remove(dir->dentry); +} + static int __init ref_tracker_debugfs_init(void) { ref_tracker_debug_dir = debugfs_create_dir("ref_tracker", NULL); -- 2.49.0