From nobody Mon Feb 9 04:28:57 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 02CBE194AEC; Tue, 8 Apr 2025 13:36:54 +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=1744119415; cv=none; b=syjYbwZKf8gFFjbq8j+k04BiGRMoV/8R8Zaae4L0B1EMSjrAQ1WoNEGdT5DwA1r1LD2k7uNqjvrkya7v+4p0M58+/Nw0BhHXXrbytZLbfgFf3dUQiCQDmYUaKtqDoJOLZH80V7rEyYtWKGZmwDyguaPyWXp+YzXKui1jcG8zVQw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744119415; c=relaxed/simple; bh=9FWqWDDMk9X5RfZvq4/RgURoBS/zCE/+xlI7ck/0dTk=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=pu9EB9+e9aQx9h2Elt4y2GrBbXKpfIpfGyJuMPGhq4KYr3ImCj3RGbYcf3FQsIn/Db6hM6wYrQ0tSxWV6R2k7WOoAn336HLqCDVgDYC7QhfCLxG7M5TMTn5l/Z52K1TajZZlvo+57kCgonwjuvqdzsGy++SQDNzCkcG5o/LJdf0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Oy6Xkwnb; 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="Oy6Xkwnb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B51CFC4CEED; Tue, 8 Apr 2025 13:36:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744119414; bh=9FWqWDDMk9X5RfZvq4/RgURoBS/zCE/+xlI7ck/0dTk=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=Oy6XkwnbF0S3k10GIE9d5bGi/sU1QnOf5X+l+wkW65zjq8N+AuqOgHEk1k/51j3P6 qtCHPZoN818vBnic9OPPz5/48LqkR62R8mtN4uBa/WXLlS+oADPB/ZkuAQro/UN++i zScHND4VhVRjqxrDjhry+BY+eJcI1UTsrgY5F+m81rUDPK8h0w+u+F6lA4r4wKE1Jn VZO+Cl4CzbEYqeXRr2iyIPB/5brdiKMiceUrAUIiCMtDpZmea0n+P6xeiI+KZ9Q7mf UYougjCxdQ+F7c2x/B2EFD6YZrRlgVWWnVB3MQWNDVt3v6sdLT8IsMMaaK9ov/VoBw 5QA76z8N8cKlQ== From: Jeff Layton Date: Tue, 08 Apr 2025 09:36:38 -0400 Subject: [PATCH v2 2/2] net: add debugfs files for showing netns refcount tracking info 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: <20250408-netns-debugfs-v2-2-ca267f51461e@kernel.org> References: <20250408-netns-debugfs-v2-0-ca267f51461e@kernel.org> In-Reply-To: <20250408-netns-debugfs-v2-0-ca267f51461e@kernel.org> To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Andrew Morton Cc: Andrew Lunn , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Jeff Layton X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=4519; i=jlayton@kernel.org; h=from:subject:message-id; bh=9FWqWDDMk9X5RfZvq4/RgURoBS/zCE/+xlI7ck/0dTk=; b=owEBbQKS/ZANAwAIAQAOaEEZVoIVAcsmYgBn9SZyg7Dj/a/HB8MgP0TlrFB5LCLoOomDN3DR6 JVk99VzQbGJAjMEAAEIAB0WIQRLwNeyRHGyoYTq9dMADmhBGVaCFQUCZ/UmcgAKCRAADmhBGVaC FdL+EACKdzEuea9Y/CWRS21SOBREThDU01A7JMW7fBRiLa7woWaBheVhFPAAD1wuo58LvfnLC04 BTH71zfdaQyjU118A+jXdZ3vg1a2Bz5KDeBeYMSg4cUkCN0beRrZxVd0PU7ahdu6J0eBqrmEw9U cMG2I8KUdyoN2MRMWC7nfIBucFiej2dGYqa7P9fvFYEA6cxsMhSSDz0kPj2GEShPajpE6TR235x QZc3QWgnY0VQx1gKwpl8c2zFt+DlspANvwLwckcz/+/dSwdMifiQkCr2+Fe3C0Wg65gtpwEuNir 8CSCXFq7/9kotq96bTSufQVoonkdwr4rHRBDmgQwzNZH36St2znhLOWxAHJNBl0OjBsrGU9RNmN vPFNHGg28N+LhnwjrWn3DbS4znvUJylLBhLAwCJoaL9ShIoHZfY5bWJ1UlE8Iiqs9LHs/7bcGHI KkpA7KTpGJ9k0C7KUCnNMi+w9FSQUGF4bTN2IoFtwCAlgcVjlBgCBJS/rrT+tco6WyGbKzUP9e2 U+sovwn564nhp64zT6kOJFOBsdjC82EgRd1LRIFTceuk1dEuwKfQSYQQW7jLIqltuTissW/b1Hk PSOLAxmvEmAuobFfzU94Aklzx0WZjc42AuvT1nnkQu2RkGeS78oOQZqLaCnNcfHlAgVZnNa7lq2 uNmZz+qnkUel3xg== X-Developer-Key: i=jlayton@kernel.org; a=openpgp; fpr=4BC0D7B24471B2A184EAF5D3000E684119568215 CONFIG_NET_NS_REFCNT_TRACKER currently has no convenient way to display its tracking info. Add a new net_ns directory under the debugfs ref_tracker directory. Create a directory in there for every netns, with refcnt and notrefcnt files that show the currently tracked active and passive references. Signed-off-by: Jeff Layton --- net/core/net_namespace.c | 151 +++++++++++++++++++++++++++++++++++++++++++= ++++ 1 file changed, 151 insertions(+) diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 4303f2a4926243e2c0ff0c0387383cd8e0658019..7e9dc487f46d656ee4ae3d6d18d= 35bb2aba2b176 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -1512,3 +1512,154 @@ const struct proc_ns_operations netns_operations = =3D { .owner =3D netns_owner, }; #endif + +#ifdef CONFIG_DEBUG_FS +#ifdef CONFIG_NET_NS_REFCNT_TRACKER + +#include + +static struct dentry *ns_ref_tracker_dir; +static unsigned int ns_debug_net_id; + +struct ns_debug_net { + struct dentry *netdir; + struct dentry *refcnt; + struct dentry *notrefcnt; +}; + +#define MAX_NS_DEBUG_BUFSIZE (32 * PAGE_SIZE) + +static int +ns_debug_tracker_show(struct seq_file *f, void *v) +{ + struct ref_tracker_dir *tracker =3D f->private; + int len, bufsize =3D PAGE_SIZE; + char *buf; + + for (;;) { + buf =3D kvmalloc(bufsize, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + len =3D ref_tracker_dir_snprint(tracker, buf, bufsize); + if (len < bufsize) + break; + + kvfree(buf); + bufsize *=3D 2; + if (bufsize > MAX_NS_DEBUG_BUFSIZE) + return -ENOBUFS; + } + seq_write(f, buf, len); + kvfree(buf); + return 0; +} + +static int +ns_debug_ref_open(struct inode *inode, struct file *filp) +{ + int ret; + struct net *net =3D inode->i_private; + + ret =3D single_open(filp, ns_debug_tracker_show, &net->refcnt_tracker); + if (!ret) + net_passive_inc(net); + return ret; +} + +static int +ns_debug_notref_open(struct inode *inode, struct file *filp) +{ + int ret; + struct net *net =3D inode->i_private; + + ret =3D single_open(filp, ns_debug_tracker_show, &net->notrefcnt_tracker); + if (!ret) + net_passive_inc(net); + return ret; +} + +static int +ns_debug_ref_release(struct inode *inode, struct file *filp) +{ + struct net *net =3D inode->i_private; + + net_passive_dec(net); + return single_release(inode, filp); +} + +static const struct file_operations ns_debug_ref_fops =3D { + .owner =3D THIS_MODULE, + .open =3D ns_debug_ref_open, + .read =3D seq_read, + .llseek =3D seq_lseek, + .release =3D ns_debug_ref_release, +}; + +static const struct file_operations ns_debug_notref_fops =3D { + .owner =3D THIS_MODULE, + .open =3D ns_debug_notref_open, + .read =3D seq_read, + .llseek =3D seq_lseek, + .release =3D ns_debug_ref_release, +}; + +static int +ns_debug_init_net(struct net *net) +{ + struct ns_debug_net *dnet =3D net_generic(net, ns_debug_net_id); + char name[11]; /* 10 decimal digits + NULL term */ + int len; + + len =3D snprintf(name, sizeof(name), "%u", net->ns.inum); + if (len >=3D sizeof(name)) + return -EOVERFLOW; + + dnet->netdir =3D debugfs_create_dir(name, ns_ref_tracker_dir); + if (IS_ERR(dnet->netdir)) + return PTR_ERR(dnet->netdir); + + dnet->refcnt =3D debugfs_create_file("refcnt", S_IFREG | 0400, dnet->netd= ir, + net, &ns_debug_ref_fops); + if (IS_ERR(dnet->refcnt)) { + debugfs_remove(dnet->netdir); + return PTR_ERR(dnet->refcnt); + } + + dnet->notrefcnt =3D debugfs_create_file("notrefcnt", S_IFREG | 0400, dnet= ->netdir, + net, &ns_debug_notref_fops); + if (IS_ERR(dnet->notrefcnt)) { + debugfs_remove_recursive(dnet->netdir); + return PTR_ERR(dnet->notrefcnt); + } + + return 0; +} + +static void +ns_debug_exit_net(struct net *net) +{ + struct ns_debug_net *dnet =3D net_generic(net, ns_debug_net_id); + + debugfs_remove_recursive(dnet->netdir); +} + +static struct pernet_operations ns_debug_net_ops =3D { + .init =3D ns_debug_init_net, + .exit =3D ns_debug_exit_net, + .id =3D &ns_debug_net_id, + .size =3D sizeof(struct ns_debug_net), +}; + +static int __init ns_debug_init(void) +{ + ns_ref_tracker_dir =3D debugfs_create_dir("net_ns", ref_tracker_debug_dir= ); + if (IS_ERR(ns_ref_tracker_dir)) + return PTR_ERR(ns_ref_tracker_dir); + + register_pernet_subsys(&ns_debug_net_ops); + return 0; +} +late_initcall(ns_debug_init); +#endif /* CONFIG_NET_NS_REFCNT_TRACKER */ +#endif /* CONFIG_DEBUG_FS */ --=20 2.49.0