+ ref_tracker-add-a-static-classname-string-to-each-ref_tracker_dir.patch added to mm-nonmm-unstable branch

+ ref_tracker-add-a-static-classname-string-to-each-ref_tracker_dir.patch added to mm-nonmm-unstable branch

[Andrew Morton]

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The patch titled
     Subject: ref_tracker: add a static classname string to each ref_tracker_dir
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     ref_tracker-add-a-static-classname-string-to-each-ref_tracker_dir.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/ref_tracker-add-a-static-classname-string-to-each-ref_tracker_dir.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Jeff Layton <jlayton@kernel.org>
Subject: ref_tracker: add a static classname string to each ref_tracker_dir
Date: Tue, 03 Jun 2025 07:27:15 -0400

A later patch in the series will be adding debugfs files for each
ref_tracker that get created in ref_tracker_dir_init().  The format will
be "class@%px".  The current "name" string can vary between
ref_tracker_dir objects of the same type, so it's not suitable for this
purpose.

Add a new "class" string to the ref_tracker dir that describes the the
type of object (sans any individual info for that object).

Also, in the i915 driver, gate the creation of debugfs files on whether
the dentry pointer is still set to NULL.  CI has shown that the
ref_tracker_dir can be initialized more than once.

Link: https://lkml.kernel.org/r/20250603-reftrack-dbgfs-v13-4-7b2a425019d8@kernel.org
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumaze <edumazet@google.com>
Cc: Jakub Kacinski <kuba@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Krzysztof Karas <krzysztof.karas@intel.com>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Qasim Ijaz <qasdev00@gmail.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Simon Horman <horms@kernel.org>
Cc: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Tvrtko Ursulin <tursulin@ursulin.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/gpu/drm/display/drm_dp_tunnel.c |    2 +-
 drivers/gpu/drm/i915/intel_runtime_pm.c |    4 +++-
 drivers/gpu/drm/i915/intel_wakeref.c    |    3 ++-
 include/linux/ref_tracker.h             |    4 ++++
 lib/test_ref_tracker.c                  |    2 +-
 net/core/dev.c                          |    2 +-
 net/core/net_namespace.c                |    4 ++--
 7 files changed, 14 insertions(+), 7 deletions(-)

--- a/drivers/gpu/drm/display/drm_dp_tunnel.c~ref_tracker-add-a-static-classname-string-to-each-ref_tracker_dir
+++ a/drivers/gpu/drm/display/drm_dp_tunnel.c
@@ -1920,7 +1920,7 @@ drm_dp_tunnel_mgr_create(struct drm_devi
 	}
 
 #ifdef CONFIG_DRM_DISPLAY_DP_TUNNEL_STATE_DEBUG
-	ref_tracker_dir_init(&mgr->ref_tracker, 16, "dptun");
+	ref_tracker_dir_init(&mgr->ref_tracker, 16, "drm_dptun", "dptun");
 #endif
 
 	for (i = 0; i < max_group_count; i++) {
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c~ref_tracker-add-a-static-classname-string-to-each-ref_tracker_dir
+++ a/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -59,7 +59,9 @@ static struct drm_i915_private *rpm_to_i
 
 static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
 {
-	ref_tracker_dir_init(&rpm->debug, INTEL_REFTRACK_DEAD_COUNT, dev_name(rpm->kdev));
+	if (!rpm->debug.class)
+		ref_tracker_dir_init(&rpm->debug, INTEL_REFTRACK_DEAD_COUNT,
+				     "intel_runtime_pm", dev_name(rpm->kdev));
 }
 
 static intel_wakeref_t
--- a/drivers/gpu/drm/i915/intel_wakeref.c~ref_tracker-add-a-static-classname-string-to-each-ref_tracker_dir
+++ a/drivers/gpu/drm/i915/intel_wakeref.c
@@ -114,7 +114,8 @@ void __intel_wakeref_init(struct intel_w
 			 "wakeref.work", &key->work, 0);
 
 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF)
-	ref_tracker_dir_init(&wf->debug, INTEL_REFTRACK_DEAD_COUNT, name);
+	if (!wf->debug.class)
+		ref_tracker_dir_init(&wf->debug, INTEL_REFTRACK_DEAD_COUNT, "intel_wakeref", name);
 #endif
 }
 
--- a/include/linux/ref_tracker.h~ref_tracker-add-a-static-classname-string-to-each-ref_tracker_dir
+++ a/include/linux/ref_tracker.h
@@ -19,6 +19,7 @@ struct ref_tracker_dir {
 	bool			dead;
 	struct list_head	list; /* List of active trackers */
 	struct list_head	quarantine; /* List of dead trackers */
+	const char		*class; /* object classname */
 	char			name[32];
 #endif
 };
@@ -27,6 +28,7 @@ struct ref_tracker_dir {
 
 static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
 					unsigned int quarantine_count,
+					const char *class,
 					const char *name)
 {
 	INIT_LIST_HEAD(&dir->list);
@@ -36,6 +38,7 @@ static inline void ref_tracker_dir_init(
 	dir->dead = false;
 	refcount_set(&dir->untracked, 1);
 	refcount_set(&dir->no_tracker, 1);
+	dir->class = class;
 	strscpy(dir->name, name, sizeof(dir->name));
 	stack_depot_init();
 }
@@ -60,6 +63,7 @@ int ref_tracker_free(struct ref_tracker_
 
 static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
 					unsigned int quarantine_count,
+					const char *class,
 					const char *name)
 {
 }
--- a/lib/test_ref_tracker.c~ref_tracker-add-a-static-classname-string-to-each-ref_tracker_dir
+++ a/lib/test_ref_tracker.c
@@ -64,7 +64,7 @@ static int __init test_ref_tracker_init(
 {
 	int i;
 
-	ref_tracker_dir_init(&ref_dir, 100, "selftest");
+	ref_tracker_dir_init(&ref_dir, 100, "selftest", "selftest");
 
 	timer_setup(&test_ref_tracker_timer, test_ref_tracker_timer_func, 0);
 	mod_timer(&test_ref_tracker_timer, jiffies + 1);
--- a/net/core/dev.c~ref_tracker-add-a-static-classname-string-to-each-ref_tracker_dir
+++ a/net/core/dev.c
@@ -11714,7 +11714,7 @@ struct net_device *alloc_netdev_mqs(int
 
 	dev->priv_len = sizeof_priv;
 
-	ref_tracker_dir_init(&dev->refcnt_tracker, 128, name);
+	ref_tracker_dir_init(&dev->refcnt_tracker, 128, "netdev", name);
 #ifdef CONFIG_PCPU_DEV_REFCNT
 	dev->pcpu_refcnt = alloc_percpu(int);
 	if (!dev->pcpu_refcnt)
--- a/net/core/net_namespace.c~ref_tracker-add-a-static-classname-string-to-each-ref_tracker_dir
+++ a/net/core/net_namespace.c
@@ -403,8 +403,8 @@ static __net_init void preinit_net(struc
 {
 	refcount_set(&net->passive, 1);
 	refcount_set(&net->ns.count, 1);
-	ref_tracker_dir_init(&net->refcnt_tracker, 128, "net refcnt");
-	ref_tracker_dir_init(&net->notrefcnt_tracker, 128, "net notrefcnt");
+	ref_tracker_dir_init(&net->refcnt_tracker, 128, "net_refcnt", "net_refcnt");
+	ref_tracker_dir_init(&net->notrefcnt_tracker, 128, "net_notrefcnt", "net_notrefcnt");
 
 	get_random_bytes(&net->hash_mix, sizeof(u32));
 	net->dev_base_seq = 1;
_

Patches currently in -mm which might be from jlayton@kernel.org are

ref_tracker-dont-use-%pk-in-pr_ostream-output.patch
ref_tracker-add-a-top-level-debugfs-directory-for-ref_tracker.patch
ref_tracker-have-callers-pass-output-function-to-pr_ostream.patch
ref_tracker-add-a-static-classname-string-to-each-ref_tracker_dir.patch
ref_tracker-allow-pr_ostream-to-print-directly-to-a-seq_file.patch
ref_tracker-automatically-register-a-file-in-debugfs-for-a-ref_tracker_dir.patch
ref_tracker-add-a-way-to-create-a-symlink-to-the-ref_tracker_dir-debugfs-file.patch
net-add-symlinks-to-ref_tracker_dir-for-netns.patch
ref_tracker-eliminate-the-ref_tracker_dir-name-field.patch