[RFC PATCH 6/7] audit: wake up audit_backlog_wait queue when auditd goes away.

[Richard Guy Briggs]

When auditd goes away (died, killed or shutdown, or net namespace shut
down), there is no point in sleeping waiting for auditd to drain the
queue since that message would be distined for the hold queue after the
timeout anyways.  This will needlessly have those processes wait the
full default timeout of 60 seconds (audit_backlog_wait_time).

Wake up the processes caught in the audit_backlog_wait queue when auditd
is no longer present so they can be sent instead to the hold queue.

Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
---
 kernel/audit.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/kernel/audit.c b/kernel/audit.c
index 34411af..688fa1e 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -425,6 +425,7 @@ restart:
 				audit_log_lost(s);
 				audit_pid = 0;
 				audit_sock = NULL;
+				wake_up(&audit_backlog_wait);
 			} else {
 				pr_warn("re-scheduling(#%d) write to audit_pid=%d\n",
 					attempts, audit_pid);
@@ -882,6 +883,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 			audit_pid = new_pid;
 			audit_nlk_portid = NETLINK_CB(skb).portid;
 			audit_sock = skb->sk;
+			if (!audit_pid)
+				wake_up(&audit_backlog_wait);
 		}
 		if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
 			err = audit_set_rate_limit(s.rate_limit);
@@ -1154,6 +1157,7 @@ static void __net_exit audit_net_exit(struct net *net)
 	if (sock == audit_sock) {
 		audit_pid = 0;
 		audit_sock = NULL;
+		wake_up(&audit_backlog_wait);
 	}
 
 	RCU_INIT_POINTER(aunet->nlsk, NULL);
@@ -1393,7 +1397,7 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 			sleep_time = timeout_start + audit_backlog_wait_time - jiffies;
 			if (sleep_time > 0) {
 				sleep_time = wait_for_auditd(sleep_time);
-				if (sleep_time > 0)
+				if (audit_pid && sleep_time > 0)
 					continue;
 			}
 		}
-- 
1.7.1

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