From e2fbc857d3c677ce96d9260577491e0d8f21b6f7 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Fri, 8 Dec 2023 17:52:11 -0800 Subject: [PATCH] x86/nmi: Rate limit unknown NMI messages On some AMD machines, unknown NMI messages were printed on the console continuously when using perf command with IBS. It was reported that it can slow down the kernel. Ratelimit the unknown NMI messages. Signed-off-by: Namhyung Kim Signed-off-by: Borislav Petkov (AMD) Acked-by: Ravi Bangoria Acked-by: Guilherme Amadio Acked-by: Thomas Gleixner Link: https://lore.kernel.org/r/20231209015211.357983-1-namhyung@kernel.org --- arch/x86/kernel/nmi.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index 17e955ab69fed..d238679011866 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -303,13 +303,13 @@ unknown_nmi_error(unsigned char reason, struct pt_regs *regs) __this_cpu_add(nmi_stats.unknown, 1); - pr_emerg("Uhhuh. NMI received for unknown reason %02x on CPU %d.\n", - reason, smp_processor_id()); + pr_emerg_ratelimited("Uhhuh. NMI received for unknown reason %02x on CPU %d.\n", + reason, smp_processor_id()); if (unknown_nmi_panic || panic_on_unrecovered_nmi) nmi_panic(regs, "NMI: Not continuing"); - pr_emerg("Dazed and confused, but trying to continue\n"); + pr_emerg_ratelimited("Dazed and confused, but trying to continue\n"); } NOKPROBE_SYMBOL(unknown_nmi_error);