From nobody Mon Feb 9 13:37:05 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 93F84298CA1; Mon, 28 Apr 2025 18:27:11 +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=1745864831; cv=none; b=Roja+WWdi7RIcb+gUjNg6361xghjoBOubbMRVoI5Kkv3QSW6sDXdCyOTUXZH8N+ir0h5yBRjafnDw2G8lwaR/YydV/F5FzVgKS+hkRMu2OPuVCP7hXt077fPhS8a94z6qPnULixL+u7jnDpUSl79TIPWIXXWkZazJgdwK9glU34= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745864831; c=relaxed/simple; bh=fpnw2V8uXAwDSgZ7plejSEREFoEn+a0D9Tgyy1cTvLw=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=WR20EfZZrkT/hKjvK5p9aWtExxccC+UkDlJyXVLydiC9aK9zq35PaoO9M6z2iPkfTavkG0uWBV0/FR34eYgGw1zWiLtoBEiPyiVzM7tIO4C5JOG27DqRbHote8E4p6n9oUWorUBFeQUKTZX1KxyEbJY6vEDJL2n16Ig0tNBo1Ew= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MsLeU6T/; 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="MsLeU6T/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DCD8BC4CEE4; Mon, 28 Apr 2025 18:27:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745864831; bh=fpnw2V8uXAwDSgZ7plejSEREFoEn+a0D9Tgyy1cTvLw=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=MsLeU6T/FbY5/FrdP7ESmG6hvZlKZUsncPbCgdsOLlmJW1izwqEvIJFKIIs5MKcQY p7JRTOlw+y7YbXwiLvPIj/7crvkiV7vS9iMYcjyytXP5tIcwwn6adOUrWDHcidfmwg fAPx906bVEifxrfGC6BHFutcrDQP0coSfEeBEAZyQqNNJMOp6xhWK1UdobTaUrtLnq Y8cJIKytWegW+CUMYg8Hiw0Y6ThcibWyL5MX6GeJMg9BM0IKNH6Yx5wziZcHZK2yq3 z8D22Arjo/sbaL45YbSAXVfG/0Ny81aPuhq6tyXb2wSCJvCCF04T16SrgBx0Vn8ImG cb5djjgPHwaqg== From: Jeff Layton Date: Mon, 28 Apr 2025 11:26:29 -0700 Subject: [PATCH v5 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: <20250428-reftrack-dbgfs-v5-6-1cbbdf2038bd@kernel.org> References: <20250428-reftrack-dbgfs-v5-0-1cbbdf2038bd@kernel.org> In-Reply-To: <20250428-reftrack-dbgfs-v5-0-1cbbdf2038bd@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=5257; i=jlayton@kernel.org; h=from:subject:message-id; bh=fpnw2V8uXAwDSgZ7plejSEREFoEn+a0D9Tgyy1cTvLw=; b=kA0DAAgBAA5oQRlWghUByyZiAGgPyHWjoJY4UZE5t/FLMAszlWsnxX/d3fsLLKgV3tv4W9hjo YkCMwQAAQgAHRYhBEvA17JEcbKhhOr10wAOaEEZVoIVBQJoD8h1AAoJEAAOaEEZVoIV2m4P/RgR MxWp0Y1mrrqmjWUWh2CnaGAtVyxgJX44OfhrRS3GPefiuUnSQlMSW4Rf8g4H14mUo8F9xHMJ1pO i3A2tOitKw1auei5pdV9dT8S5W9JfUMC5YRP6EIl9uC0JeESf76qFJ7NKcq03N+ZC8B4aUMQCtO Q6xq1n7q2HiwCwDgaLkdI5eVeQlh19lpdW8ptcK5x3SptcyhI4Kp30VBaU3N1A1nt2T9SiyL664 de0ASV8Yk5sMZ773qsONEVW8lmc7qE2moEq9p/GfuiCnToLRFji0Oyl9N62azzPrc8JP/6X37e1 Lgh2ECXbJoFbzpllKp/NkXQQWf0AY9yB+qj9EW0KzNs1gCJIAQYKudAF2tsxsNwuKsbhlZz9MVn +IfdMloIsrS269miW9r093Je5mQQNdYxvD3tXZ2Par3uhvmMHv1d2wTcO4m0mQOYsGmXT9mlXmw gJeuXHLuZqXJ0njVfwoh7GyC31fWWVkHrCNguJM7nnPKpj0aXZDJIEgIz9ZQoAJGOzMMHOEIBVE gC7FPqHcli/0L5Bgwpeb+KWzjg9BHbfXKwpZoGfBuBc+sfIHmITJl/ZocS89ggL3qT0/Y984pA6 eox3ojxlMrICYxNi9z65n1ntycaRJ1xIyu/zwlbw30KlN+OVufLnTdOxfNB/0xK3RmaDxx11UCZ aWBWh 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 | 72 +++++++++++++++++++++++++++++++++++++++++= ++++ 2 files changed, 86 insertions(+) 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 4857bcb6d4bf557a0089f51328e75e8209e959e6..f5424857b0fde2339cce31c6744= fd4dafbaf0d2a 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); @@ -327,6 +336,69 @@ static int ref_tracker_dir_seq_print(struct ref_tracke= r_dir *dir, struct seq_fil 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 + * @fmt: format string for filename + * @...: arguments for the format string + * + * Call this function to create a debugfs file for your ref_tracker_dir th= at + * displays the current refcounts for the object. It will be automatically + * removed when the ref_tracker_dir exits. The filename must be unique. If + * the creation fails then the pr_warn will be emitted. + */ +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