From f7a1570da91558fb85b61e53243fe3fa79e2bbae Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Wed, 4 Apr 2018 14:50:15 -0400 Subject: [PATCH] tracing: Hide global trace clock from lockdep Function tracing can trace in NMIs and such. If the TSC is determined to be unstable, the tracing clock will switch to the global clock on boot up, unless "trace_clock" is specified on the kernel command line. The global clock disables interrupts to access sched_clock_cpu(), and in doing so can be done within lockdep internals (because of function tracing and NMIs). This can trigger false lockdep splats. The trace_clock_global() is special, best not to trace the irq logic within it. Link: http://lkml.kernel.org/r/20180404145015.77bde42d@gandalf.local.home Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_clock.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_clock.c b/kernel/trace/trace_clock.c index 5fdc779f411d..d8a188e0418a 100644 --- a/kernel/trace/trace_clock.c +++ b/kernel/trace/trace_clock.c @@ -96,7 +96,7 @@ u64 notrace trace_clock_global(void) int this_cpu; u64 now; - local_irq_save(flags); + raw_local_irq_save(flags); this_cpu = raw_smp_processor_id(); now = sched_clock_cpu(this_cpu); @@ -122,7 +122,7 @@ u64 notrace trace_clock_global(void) arch_spin_unlock(&trace_clock_struct.lock); out: - local_irq_restore(flags); + raw_local_irq_restore(flags); return now; }