From nobody Mon Feb 9 07:28:21 2026 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.3]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A6A61184F; Wed, 31 Jan 2024 01:46:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.3 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706665600; cv=none; b=MLeVXIahJGJFZIKmJMffm/vwam3g2HOqFABJoLPUeqfgLKItXnb6wyLxwkS4JKc2PC8Z5u4yvFDclkOH7sIEopLD6lPMzZpmIaALnxypsbu7ybuqX49ZcKoqaLYrwm/i7/8pvby6PrB7ems/1RkIIsYfXlnd0LvcfngKgs7/lAM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706665600; c=relaxed/simple; bh=audLzJG/u2LicrrB9E66namJCHJQKdgvUE/MFP76leI=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=m6dV+Hs1Wf5KCoSDmbDXIM31ZA6LPS8etTq9sVYCvXsmuzXmz2REnlcK+69SVuzH1VcrGpG36jDja+U8/Bwj9YupCT9DpbZwZCuYAHXxac+AFXjmmQzsmL0U1Vja9RkYs5UKS61/0jL5WKU9tmCR3ydd/YBZPZfBS0jpNOHcnKw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=WtjSpLQO; arc=none smtp.client-ip=220.197.31.3 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="WtjSpLQO" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=dKPmJ u+lcxYl6ovIM36rm0EPe9TPQMidXYid3C2kUMc=; b=WtjSpLQOqIbCRgd5V6e+i xO50Pm5zY2ax4diqtPk5FzVHRRNsyEaL79h0BZc9EpazBlK+sqt6NKZIZFVJGD3k QQCdcoqbJ0247c7ZRAqIt7nv2yKiaCKjiPyC/n1jrKwdIJLaXymJAAWyoP59wY1M Mnez77jaRBYeI3qWDKKvFM= Received: from localhost.localdomain (unknown [111.202.47.2]) by gzga-smtp-mta-g0-5 (Coremail) with SMTP id _____wCHb4VAprll6Y61Bg--.3059S2; Wed, 31 Jan 2024 09:45:37 +0800 (CST) From: wangkeqi To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, fw@strlen.de, wangkeqi , kernel test robot , fengwei.yin@intel.com Subject: [PATCH net v4] connector: cn_netlink_has_listeners replaces proc_event_num_listeners Date: Wed, 31 Jan 2024 09:44:59 +0800 Message-Id: <20240131014459.411158-1-wangkeqi_chris@163.com> X-Mailer: git-send-email 2.27.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wCHb4VAprll6Y61Bg--.3059S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxtw4UZFW7Kr1rXF1kGr1rWFg_yoW7tFWrpF Z0vr9IyrWDKr17Wwn8A3Wq9r13Za4kXa1UCrWxK3s3Arn5KrykXFW8tanxZr1fJwn5Kr17 Zw47KFWa9F4DAaUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07UDR6cUUUUU= X-CM-SenderInfo: 5zdqwy5htlsupkul2qqrwthudrp/1tbiVAd23GVOBTajSQAAsL Content-Type: text/plain; charset="utf-8" From: wangkeqi It is inaccurate to judge whether proc_event_num_listeners is cleared by cn_netlink_send_mult returning -ESRCH. In the case of stress-ng netlink-proc, -ESRCH will always be returned, because netlink_broadcast_filtered will return -ESRCH, which may cause stress-ng netlink-proc performance degradation. If the judgment condition is modified to whether there is a listener. proc_event_num_listeners will still be wrong due to concurrency. So replace the counter with cn_netlink_has_listeners Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202401112259.b23a1567-oliver.sang@in= tel.com Fixes: c46bfba1337d ("connector: Fix proc_event_num_listeners count not cle= ared") Signed-off-by: wangkeqi Cc: fengwei.yin@intel.com Cc: fw@strlen.de --- drivers/connector/cn_proc.c | 33 +++++++++++++++++++++------------ drivers/connector/connector.c | 9 +++++++++ include/linux/connector.h | 1 + 3 files changed, 31 insertions(+), 12 deletions(-) diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c index 3d5e6d705..4898e974c 100644 --- a/drivers/connector/cn_proc.c +++ b/drivers/connector/cn_proc.c @@ -85,6 +85,16 @@ static int cn_filter(struct sock *dsk, struct sk_buff *s= kb, void *data) return 1; } =20 +static int cn_netlink_has_listeners(void) +{ + struct sock *sk =3D get_cdev_nls(); + + if (sk) + return netlink_has_listeners(sk, CN_IDX_PROC); + else + return 0; +} + static inline void send_msg(struct cn_msg *msg) { __u32 filter_data[2]; @@ -108,9 +118,8 @@ static inline void send_msg(struct cn_msg *msg) filter_data[1] =3D 0; } =20 - if (cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT, - cn_filter, (void *)filter_data) =3D=3D -ESRCH) - atomic_set(&proc_event_num_listeners, 0); + cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT, + cn_filter, (void *)filter_data); =20 local_unlock(&local_event.lock); } @@ -122,7 +131,7 @@ void proc_fork_connector(struct task_struct *task) __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); struct task_struct *parent; =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -151,7 +160,7 @@ void proc_exec_connector(struct task_struct *task) struct proc_event *ev; __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -176,7 +185,7 @@ void proc_id_connector(struct task_struct *task, int wh= ich_id) __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); const struct cred *cred; =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -213,7 +222,7 @@ void proc_sid_connector(struct task_struct *task) struct proc_event *ev; __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -237,7 +246,7 @@ void proc_ptrace_connector(struct task_struct *task, in= t ptrace_id) struct proc_event *ev; __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -269,7 +278,7 @@ void proc_comm_connector(struct task_struct *task) struct proc_event *ev; __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -295,7 +304,7 @@ void proc_coredump_connector(struct task_struct *task) struct task_struct *parent; __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -328,7 +337,7 @@ void proc_exit_connector(struct task_struct *task) struct task_struct *parent; __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); @@ -370,7 +379,7 @@ static void cn_proc_ack(int err, int rcvd_seq, int rcvd= _ack) struct proc_event *ev; __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); =20 - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; =20 msg =3D buffer_to_cn_msg(buffer); diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c index 7f7b94f61..42bcb39ba 100644 --- a/drivers/connector/connector.c +++ b/drivers/connector/connector.c @@ -129,6 +129,15 @@ int cn_netlink_send(struct cn_msg *msg, u32 portid, u3= 2 __group, } EXPORT_SYMBOL_GPL(cn_netlink_send); =20 +struct sock *get_cdev_nls(void) +{ + if (cn_already_initialized =3D=3D 1) + return cdev.nls; + else + return NULL; +} +EXPORT_SYMBOL_GPL(get_cdev_nls); + /* * Callback helper - queues work and setup destructor for given data. */ diff --git a/include/linux/connector.h b/include/linux/connector.h index cec2d99ae..255466aea 100644 --- a/include/linux/connector.h +++ b/include/linux/connector.h @@ -127,6 +127,7 @@ int cn_netlink_send_mult(struct cn_msg *msg, u16 len, u= 32 portid, */ int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 group, gfp_t gfp_m= ask); =20 +struct sock *get_cdev_nls(void); int cn_queue_add_callback(struct cn_queue_dev *dev, const char *name, const struct cb_id *id, void (*callback)(struct cn_msg *, struct netlink_skb_parms *)); --=20 2.27.0