tree 36602d82229665a0e1375017a78353d21154610f
parent 927e56db6253225166d521cee3772624347b5cd5
author Steven Rostedt (VMware) <rostedt@goodmis.org> 1522867815 -0400
committer Steven Rostedt (VMware) <rostedt@goodmis.org> 1523019412 -0400

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) <rostedt@goodmis.org>