From nobody Mon Feb 9 15:45:22 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0F8E326139C; Wed, 30 Apr 2025 15:07:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746025629; cv=none; b=Pkt5PudzwgNMWX/UVnZeidEz5+gabSSGBkV+13zFhy4DpS0gNxGUMR/yVuGgcm2E1pJLW5dBjDkj937Q14lu9ILylEJRJ3jux8Q62E8t5sXMjnK5P2g0iwzPPPsIELzGc3fabf8cafsQ1BXBKq+AxnDNFrUz4aLKVnN4zXuphpo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746025629; c=relaxed/simple; bh=fKwdzrNkBVnGeIy3K4ltVt8KOl+gKU1yoyKwM/eux4k=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=nK1XhLT2HXYmU0gKPMQo6lSlPP/MH9AOpwydIqesL0viDKfPMwA6fL4nM1tZrHfBi1tJKyMYAQSrLrsQ4FhLbhbw0EwhPZZzoXAMLXATYKZsGJi/mIQvMNoAzMiAOFXmkAuJdyeTq6q4MnkgUNjukaMVy1IgmifoGDhZHx9pCnM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qSz/1MDZ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="qSz/1MDZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 07A24C4CEEF; Wed, 30 Apr 2025 15:07:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746025628; bh=fKwdzrNkBVnGeIy3K4ltVt8KOl+gKU1yoyKwM/eux4k=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=qSz/1MDZEZVgLJeY9n8vKJ6tTBS8g8NuOZGfsG0LFGwDxGuSVSx6cXoJYlPOlJosR MZD1yl+QVBH+gVi2LsTxfXQU6Gz3Ips2kqJa3u9GZDJY9dvFQepWprR5l5HclAVFPp O7+erA56WJEtbjB5HHMH9F4/PcaJxeh8C++9VLENWEgUV77Grg2fpvzviJROPyyUox rd4z2Ehi3qgzRitfvyAG7/BnR5lec/nhp0eKm2itZ+cNx9vdBK0Ib0oxRmLQbYWmJJ dJ8G1A7ziHH7Ymyvz7t9980WduKC9wJ4UPoGZZWGb1mC0SyzaW82/aeXZv+GlL1npU diqgB3sIlXSWA== From: Jeff Layton Date: Wed, 30 Apr 2025 08:06:52 -0700 Subject: [PATCH v6 06/10] ref_tracker: automatically register a file in debugfs for a ref_tracker_dir Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250430-reftrack-dbgfs-v6-6-867c29aff03a@kernel.org> References: <20250430-reftrack-dbgfs-v6-0-867c29aff03a@kernel.org> In-Reply-To: <20250430-reftrack-dbgfs-v6-0-867c29aff03a@kernel.org> To: Andrew Morton , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin Cc: Kuniyuki Iwashima , Qasim Ijaz , Nathan Chancellor , Andrew Lunn , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, Jeff Layton X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=5545; i=jlayton@kernel.org; h=from:subject:message-id; bh=fKwdzrNkBVnGeIy3K4ltVt8KOl+gKU1yoyKwM/eux4k=; b=owEBbQKS/ZANAwAIAQAOaEEZVoIVAcsmYgBoEjyUNnGQS0OYEdA4brxErxtiTXBj5ZSusgfCk UnOz8CB8vCJAjMEAAEIAB0WIQRLwNeyRHGyoYTq9dMADmhBGVaCFQUCaBI8lAAKCRAADmhBGVaC FTTYD/9meNbu8lLPrSnzpnTzU3KCwZP8U4SJlUXEnGkMatFWdm1oy1T6aTjTbnDGTc4vyCQkmYK FCVwNKDBk+L1kdwJtLJOk3n3+sRN17coPbBDS7T+xwISzd1gWvaS63jEpDCqtvG/E8bMsJj80Mn eMXq7lCvtP4PQjOnN9b/NjwP/GGwRf3iFeWT8ijeFQW2NYWLBEAfKjJnVc3fmqyZofQrKHXPHvR kY0BR4/yQuIF+g0OnOrTRdVqwBakOnF3QmfJ1PIRwtBl+f9MsSmtQN/0U+QrzWbYmlahrcCzq82 mkjoSVu4nQB7X6OahhYZtpbR8m1aPgr+kStAbVJrbMgYk0ufEP8Rw4xR2UTiSFXeMVQHyjOLUQy 7fQ6d0zfS80hWBJEAiVCoOGu/XLbP7IG8PwhLsIBHH05kiQnfqxJslhlScRGXtu89lath+REsBk NkGjLmRm3fhRfTva13Auj9luRvT24fMd4gXB//nybIdD9hFLFElCXBZs9HgWT/Orbpp+IzHSlbi 09M7tnEFN+7PFuNXKC0zmWLeRg4YzI2bdZTxbBt+WupDxZCZ5L79gOnN9rLmH+/7ABuMKYvQGOS 92BOJOhwGV6SQTwBKT2cLLhKk2bsvsoDj9126m3vaGaWlQL3D5Rel202YHe3Yrl5iXyfv3kOOV5 Mu1hl8JvUE65daA== X-Developer-Key: i=jlayton@kernel.org; a=openpgp; fpr=4BC0D7B24471B2A184EAF5D3000E684119568215 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 --- include/linux/ref_tracker.h | 14 +++++++++ lib/ref_tracker.c | 73 +++++++++++++++++++++++++++++++++++++++++= ++-- 2 files changed, 85 insertions(+), 2 deletions(-) diff --git a/include/linux/ref_tracker.h b/include/linux/ref_tracker.h index 2adae128d4b5e45f156af4775a1d184bb596fa91..c6e65d7ef4d4fc74c60fcabd191= 66c131d4173e2 100644 --- a/include/linux/ref_tracker.h +++ b/include/linux/ref_tracker.h @@ -5,6 +5,7 @@ #include #include #include +#include =20 struct ref_tracker; =20 @@ -18,12 +19,17 @@ 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 }; =20 #ifdef CONFIG_REF_TRACKER =20 +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, @@ -37,7 +43,11 @@ static inline void ref_tracker_dir_init(struct ref_track= er_dir *dir, refcount_set(&dir->untracked, 1); refcount_set(&dir->no_tracker, 1); dir->class =3D class; +#ifdef CONFIG_DEBUG_FS + dir->dentry =3D NULL; +#endif strscpy(dir->name, name, sizeof(dir->name)); + ref_tracker_dir_debugfs(dir); stack_depot_init(); } =20 @@ -66,6 +76,10 @@ static inline void ref_tracker_dir_init(struct ref_track= er_dir *dir, { } =20 +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 b69c11e83c18c19aaa2dc23f802291d4a7e82a66..3ee4fd0f33407881cfa140dcb7d= 8b40e3c2722de 100644 --- a/lib/ref_tracker.c +++ b/lib/ref_tracker.c @@ -31,6 +31,14 @@ struct ref_tracker_dir_stats { } stacks[]; }; =20 +#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) { @@ -197,6 +205,7 @@ void ref_tracker_dir_exit(struct ref_tracker_dir *dir) bool leak =3D false; =20 dir->dead =3D 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); @@ -313,8 +322,7 @@ EXPORT_SYMBOL_GPL(ref_tracker_free); #ifdef CONFIG_DEBUG_FS #include =20 -static __maybe_unused int -ref_tracker_dir_seq_print(struct ref_tracker_dir *dir, struct seq_file *se= q) +static int ref_tracker_dir_seq_print(struct ref_tracker_dir *dir, struct s= eq_file *seq) { struct ostream os =3D { .func =3D pr_ostream_seq, .prefix =3D "", @@ -328,6 +336,67 @@ ref_tracker_dir_seq_print(struct ref_tracker_dir *dir,= struct seq_file *seq) return os.used; } =20 +static int ref_tracker_debugfs_show(struct seq_file *f, void *v) +{ + struct ref_tracker_dir *dir =3D 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 =3D inode->i_private; + + return single_open(filp, ref_tracker_debugfs_show, dir); +} + +static const struct file_operations ref_tracker_debugfs_fops =3D { + .owner =3D THIS_MODULE, + .open =3D ref_tracker_debugfs_open, + .read =3D seq_read, + .llseek =3D seq_lseek, + .release =3D 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 =3D snprintf(name, sizeof(name), "%s@%px", dir->class, dir); + name[sizeof(name) - 1] =3D '\0'; + + if (ret < sizeof(name)) + dir->dentry =3D debugfs_create_file(name, S_IFREG | 0400, + ref_tracker_debug_dir, dir, + &ref_tracker_debugfs_fops); + else + dir->dentry =3D 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 =3D debugfs_create_dir("ref_tracker", NULL); --=20 2.49.0