From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Paris Subject: [PATCH] ratelimit printk messages from the audit system Date: Wed, 23 Jan 2008 14:50:08 -0500 Message-ID: <1201117808.3295.20.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-audit-bounces@redhat.com Errors-To: linux-audit-bounces@redhat.com To: linux-audit List-Id: linux-audit@redhat.com Some printk messages from the audit system can become excessive. This patch ratelimits those messages. It was found that messages, such as the audit backlog lost printk message could flood the logs to the point that a machine could take an nmi watchdog hit or otherwise become unresponsive. Signed-off-by: Eric Paris --- kernel/audit.c | 28 ++++++++++++++++++---------- 1 files changed, 18 insertions(+), 10 deletions(-) diff --git a/kernel/audit.c b/kernel/audit.c index f93c271..a3d828b 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -163,7 +163,8 @@ void audit_panic(const char *message) case AUDIT_FAIL_SILENT: break; case AUDIT_FAIL_PRINTK: - printk(KERN_ERR "audit: %s\n", message); + if (printk_ratelimit()) + printk(KERN_ERR "audit: %s\n", message); break; case AUDIT_FAIL_PANIC: panic("audit: %s\n", message); @@ -231,11 +232,13 @@ void audit_log_lost(const char *message) } if (print) { - printk(KERN_WARNING - "audit: audit_lost=%d audit_rate_limit=%d audit_backlog_limit=%d\n", - atomic_read(&audit_lost), - audit_rate_limit, - audit_backlog_limit); + if (printk_ratelimit()) + printk(KERN_WARNING + "audit: audit_lost=%d audit_rate_limit=%d " + "audit_backlog_limit=%d\n", + atomic_read(&audit_lost), + audit_rate_limit, + audit_backlog_limit); audit_panic(message); } } @@ -405,7 +408,11 @@ static int kauditd_thread(void *dummy) audit_pid = 0; } } else { - printk(KERN_NOTICE "%s\n", skb->data + NLMSG_SPACE(0)); + if (printk_ratelimit()) + printk(KERN_NOTICE "%s\n", skb->data + + NLMSG_SPACE(0)); + else + audit_log_lost("printk limit exceeded\n"); kfree_skb(skb); } } else { @@ -1164,7 +1171,7 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, remove_wait_queue(&audit_backlog_wait, &wait); continue; } - if (audit_rate_check()) + if (audit_rate_check() && printk_ratelimit()) printk(KERN_WARNING "audit: audit_backlog=%d > " "audit_backlog_limit=%d\n", @@ -1433,9 +1440,10 @@ void audit_log_end(struct audit_buffer *ab) skb_queue_tail(&audit_skb_queue, ab->skb); ab->skb = NULL; wake_up_interruptible(&kauditd_wait); - } else { + } else if (printk_ratelimit()) printk(KERN_NOTICE "%s\n", ab->skb->data + NLMSG_SPACE(0)); - } + else + audit_log_lost("printk limit exceeded\n"); } audit_buffer_free(ab); }