[PATCH] x86: ratelimit NMI messages

[Robert Richter]

In case of a storm of unknown NMIs the cpu get stucked. This patch
adds ratelimits to avoid this.

Signed-off-by: Robert Richter <robert.richter@xxxxxxx>
---
 arch/x86/kernel/traps.c |   16 +++++++++-------
 1 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 60788de..97a492d 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -366,15 +366,17 @@ unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
 		return;
 	}
 #endif
-	printk(KERN_EMERG
-		"Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
-			reason, smp_processor_id());
-
-	printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n");
+	if (printk_ratelimit()) {
+		printk(KERN_EMERG "Uhhuh. NMI received for unknown reason"
+		       " %02x on CPU %d.\n", reason, smp_processor_id());
+		printk(KERN_EMERG
+		       "Do you have a strange power saving mode enabled?\n");
+	}
 	if (panic_on_unrecovered_nmi)
 		panic("NMI: Not continuing");
-
-	printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
+	if (printk_ratelimit())
+		printk(KERN_EMERG
+		       "Dazed and confused, but trying to continue\n");
 }
 
 static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
-- 
1.7.1.1



-- 
Advanced Micro Devices, Inc.
Operating System Research Center

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