linux-kernel - [PATCH x86 for review III] [8/29] x86_64: avoid warning message livelock

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 for Android: free password hash cracker in your pocket

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

Message-Id: <20070212165128.2460213FC3@wotan.suse.de>
Date:	Mon, 12 Feb 2007 17:51:28 +0100 (CET)
From:	Andi Kleen <ak@...e.de>
To:	Roland Dreier <rdreier@...co.com>, patches@...-64.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH x86 for review III] [8/29] x86_64: avoid warning message livelock


From: Roland Dreier <rdreier@...co.com>

I've seen my box paralyzed by an endless spew of

    rtc: lost some interrupts at 1024Hz.

messages on the serial console.  What seems to be happening is that
something real causes an interrupt to be lost and triggers the
message.  But then printing the message to the serial console (from
the hpet interrupt handler) takes more than 1/1024th of a second, and
then some more interrupts are lost, so the message triggers again....

Fix this by adding a printk_ratelimit() before printing the warning.

Signed-off-by: Roland Dreier <rolandd@...co.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Andi Kleen <ak@...e.de>

---

 arch/x86_64/kernel/time.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Index: linux/arch/x86_64/kernel/time.c
===================================================================
--- linux.orig/arch/x86_64/kernel/time.c
+++ linux/arch/x86_64/kernel/time.c
@@ -1226,8 +1226,9 @@ static void hpet_rtc_timer_reinit(void)
 		if (PIE_on)
 			PIE_count += lost_ints;
 
-		printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n",
-		       hpet_rtc_int_freq);
+		if (printk_ratelimit())
+			printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n",
+			       hpet_rtc_int_freq);
 	}
 }
 
-
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/