Messages in this thread Patch in this message | | | From | wangkeqi <> | Subject | [PATCH net v3] connector: cn_netlink_has_listeners replaces proc_event_num_listeners | Date | Wed, 24 Jan 2024 19:44:37 +0800 |
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From: wangkeqi <wangkeqiwang@didiglobal.com>
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 <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202401112259.b23a1567-oliver.sang@intel.com Fixes: c46bfba133 ("connector: Fix proc_event_num_listeners count not cleared") Signed-off-by: wangkeqi <wangkeqiwang@didiglobal.com> 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 *skb, void *data) return 1; } +static int cn_netlink_has_listeners(void) +{ + struct sock *sk = 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] = 0; } - if (cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT, - cn_filter, (void *)filter_data) == -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); 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; - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; msg = 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); - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; msg = buffer_to_cn_msg(buffer); @@ -176,7 +185,7 @@ void proc_id_connector(struct task_struct *task, int which_id) __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); const struct cred *cred; - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; msg = 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); - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; msg = buffer_to_cn_msg(buffer); @@ -237,7 +246,7 @@ void proc_ptrace_connector(struct task_struct *task, int ptrace_id) struct proc_event *ev; __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8); - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; msg = 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); - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; msg = 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); - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; msg = 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); - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; msg = 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); - if (atomic_read(&proc_event_num_listeners) < 1) + if (!cn_netlink_has_listeners()) return; msg = 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, u32 __group, } EXPORT_SYMBOL_GPL(cn_netlink_send); +struct sock *get_cdev_nls(void) +{ + if (cn_already_initialized == 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, u32 portid, */ int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 group, gfp_t gfp_mask); +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 *)); -- 2.27.0
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