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 | 13 ++++++++
lib/ref_tracker.c | 73 +++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 84 insertions(+), 2 deletions(-)
diff --git a/include/linux/ref_tracker.h b/include/linux/ref_tracker.h
index
3968f993db81e95c0d58c81454311841c1b9cd35..17d5924d595ce95bfb5d8ec6d813490499bd89d0
100644
--- a/include/linux/ref_tracker.h
+++ b/include/linux/ref_tracker.h
@@ -20,12 +20,17 @@ 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
+void ref_tracker_dir_debugfs(struct ref_tracker_dir *dir);
+
static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
unsigned int quarantine_count,
const char *class,
@@ -39,7 +44,11 @@ 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 +77,10 @@ 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
66a765cdfc471968fd6434dafc5b654962f20667..723df31321242d6af267986cc56a9d80b6e5ad18
100644
--- a/lib/ref_tracker.c
+++ b/lib/ref_tracker.c
@@ -31,6 +31,14 @@ 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)
{
@@ -195,6 +203,7 @@ 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 @@ EXPORT_SYMBOL_GPL(ref_tracker_free);
#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>
-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
