linux-kernel - RE: [rfc] suppress excessive AER output

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 4 Aug 2011 13:54:19 +0800
From:	"Zhang, Yanmin" <yanmin.zhang@...el.com>
To:	Dave Jones <davej@...hat.com>,
	Linux Kernel <linux-kernel@...r.kernel.org>
CC:	"Nguyen, Tom L" <tom.l.nguyen@...el.com>,
	"Huang, Ying" <ying.huang@...el.com>
Subject: RE: [rfc] suppress excessive AER output

Dave,

How about adding a new module parameter aer_printk_limit, so user space could reset it any time?

Yanmin

-----Original Message-----
From: Dave Jones [mailto:davej@...hat.com] 
Sent: Thursday, August 04, 2011 6:34 AM
To: Linux Kernel
Cc: Nguyen, Tom L; Zhang, Yanmin
Subject: [rfc] suppress excessive AER output

I have a machine that has developed some kind of problem with
its onboard ethernet.  It still boots, but spewed almost 1.5G of text
(2381585 instances of the warning below) before we realised what
was going on, and blacklisted the igb driver.

Is it worth logging every single error when we're flooding like this ?
It seems unlikely that we'll find useful information in amongst that much data
that wasn't already in the first 100 instances.

I picked 100 in the (untested) example patch below arbitarily, but the exact
value could be smaller, or slightly bigger..

could we do something like this maybe ?

	Dave

diff --git a/drivers/pci/pcie/aer/aerdrv_errprint.c b/drivers/pci/pcie/aer/aerdrv_errprint.c
index 3ea5173..4ec88c6 100644
--- a/drivers/pci/pcie/aer/aerdrv_errprint.c
+++ b/drivers/pci/pcie/aer/aerdrv_errprint.c
@@ -153,6 +153,17 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
 {
 	int id = ((dev->bus->number << 8) | dev->devfn);
 	char prefix[44];
+	static unsigned long aer_printk_limit = 0;
+
+	aer_printk_limit++;
+
+	if (aer_printk_limit > 100)
+		return;
+
+	if (aer_printk_limit == 100) {
+		printk(KERN_ERR "Reached limit of 100 AER errors. Further AER output suppressed.\n");
+		return;
+	}

 	snprintf(prefix, sizeof(prefix), "%s%s %s: ",
 		 (info->severity == AER_CORRECTABLE) ? KERN_WARNING : KERN_ERR,
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/