From 344da544f177f919cf6919e5abcd388f27aa53db Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 16 Dec 2022 16:52:01 -0800 Subject: x86/nmi: Print reasons why backtrace NMIs are ignored Instrument nmi_trigger_cpumask_backtrace() to dump out diagnostics based on evidence accumulated by exc_nmi(). These diagnostics are dumped for CPUs that ignored an NMI backtrace request for more than 10 seconds. [ paulmck: Apply Ingo Molnar feedback. ] Signed-off-by: Paul E. McKenney Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: Reviewed-by: Ingo Molnar --- lib/nmi_backtrace.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'lib') diff --git a/lib/nmi_backtrace.c b/lib/nmi_backtrace.c index d01aec6ae15c..5274bbb026d7 100644 --- a/lib/nmi_backtrace.c +++ b/lib/nmi_backtrace.c @@ -64,6 +64,7 @@ void nmi_trigger_cpumask_backtrace(const cpumask_t *mask, if (!cpumask_empty(to_cpumask(backtrace_mask))) { pr_info("Sending NMI from CPU %d to CPUs %*pbl:\n", this_cpu, nr_cpumask_bits, to_cpumask(backtrace_mask)); + nmi_backtrace_stall_snap(to_cpumask(backtrace_mask)); raise(to_cpumask(backtrace_mask)); } @@ -74,6 +75,7 @@ void nmi_trigger_cpumask_backtrace(const cpumask_t *mask, mdelay(1); touch_softlockup_watchdog(); } + nmi_backtrace_stall_check(to_cpumask(backtrace_mask)); /* * Force flush any remote buffers that might be stuck in IRQ context -- cgit v1.2.3