[ARCHIVE DEBUG 09/13] netlink_debug: instrument timing of calls by init/systemd or audit_pid

[Richard Guy Briggs]

Debug the timing and stalling of calls to netlink_sendmsg() for
processes we care about with any error return values.

Signed-off-by: Richard Guy Briggs <rgb at redhat.com>
---
 net/netlink/af_netlink.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 05919bf..ba5eedf 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2256,6 +2256,8 @@ static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
 	put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
 }
 
+extern int audit_pid;
+
 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
 			   struct msghdr *msg, size_t len)
 {
@@ -2268,10 +2270,19 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
 	int err;
 	struct scm_cookie scm;
 	u32 netlink_skb_flags = 0;
+	//unsigned long trytime = 0;
+	unsigned long trytime = jiffies;
+	pid_t audit_pid_cached = audit_pid;
+	int pr;
 
 	if (msg->msg_flags&MSG_OOB)
 		return -EOPNOTSUPP;
 
+	if (current->tgid == 1 || (audit_pid && audit_pid == current->tgid))
+		//pr_warn("( %lu )netlink_sendmsg apid=%d pid=%d(%s)\n",
+			//trytime = jiffies, audit_pid, current->pid, current->comm);
+		pr = 1;
+
 	err = scm_send(sock, msg, &scm, true);
 	if (err < 0)
 		return err;
@@ -2343,6 +2354,11 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
 
 out:
 	scm_destroy(&scm);
+
+	if (pr || current->tgid == 1 || (audit_pid && audit_pid == current->tgid))
+		pr_warn("( %lu %lu )netlink_sendmsg-exit apid=%d apid-old=%d pid=%d(%s) err=%d\n",
+			trytime, jiffies - trytime, audit_pid, audit_pid_cached, current->pid, current->comm, err);
+
 	return err;
 }
 
-- 
1.7.1