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Commit 126df08c authored by Denis Kirjanov's avatar Denis Kirjanov Committed by Michael Ellerman
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powerpc/pseries: Don't trace hcalls on offline CPUs 



If a cpu is hotplugged while the hcall trace points are active, it's
possible to hit a warning from RCU due to the trace points calling into
RCU from an offline cpu, eg:

  RCU used illegally from offline CPU!
  rcu_scheduler_active = 1, debug_locks = 1

Make the hypervisor tracepoints conditional by using
TRACE_EVENT_FN_COND.

Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarDenis Kirjanov <kda@linux-powerpc.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent f15838e9

arch/powerpc/include/asm/trace.h

+6 −2
Original line number Diff line number Diff line
@@ -57,12 +57,14 @@ DEFINE_EVENT(ppc64_interrupt_class, timer_interrupt_exit, 
extern void hcall_tracepoint_regfunc(void);

extern void hcall_tracepoint_unregfunc(void);



TRACE_EVENT_FN(hcall_entry,

TRACE_EVENT_FN_COND(hcall_entry,



	TP_PROTO(unsigned long opcode, unsigned long *args),



	TP_ARGS(opcode, args),



	TP_CONDITION(cpu_online(raw_smp_processor_id())),



	TP_STRUCT__entry(

		__field(unsigned long, opcode)

	),
@@ -76,13 +78,15 @@ TRACE_EVENT_FN(hcall_entry, 
	hcall_tracepoint_regfunc, hcall_tracepoint_unregfunc

);



TRACE_EVENT_FN(hcall_exit,

TRACE_EVENT_FN_COND(hcall_exit,



	TP_PROTO(unsigned long opcode, unsigned long retval,

		unsigned long *retbuf),



	TP_ARGS(opcode, retval, retbuf),



	TP_CONDITION(cpu_online(raw_smp_processor_id())),



	TP_STRUCT__entry(

		__field(unsigned long, opcode)

		__field(unsigned long, retval)