On Thursday, October 22, 2015 02:53:19 PM Richard Guy Briggs wrote:
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(a)redhat.com>
---
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);
I'm thinking it might be time for two small, static helper functions,
auditd_register() and auditd_unregister() (or similar, feel free to suggest
other names), that set/reset the various auditd state variables and handle the
wake_up() call. We're duplicating some code that is starting to get non-
trivial.
I'd also add a comment about why you are calling wake_up() in the unregister
function.
@@ -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;
Perhaps handle this in wait_for_auditd()? Right now this is the only caller,
but if we use it elsewhere it seems like we would want the same logic.
--
paul moore
www.paul-moore.com