Commit-ID: 4787c368a9bca39e173d702389ee2eaf0520abc1 Gitweb: http://git.kernel.org/tip/4787c368a9bca39e173d702389ee2eaf0520abc1 Author: Seiji Aguchi <seiji.agu...@hds.com> AuthorDate: Fri, 28 Jun 2013 14:02:11 -0400 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Tue, 2 Jul 2013 09:52:31 +0200
x86/tracing: Add irq_enter/exit() in smp_trace_reschedule_interrupt() Reschedule vector tracepoints may be called in cpu idle state. This causes lockdep check warning below. The tracepoint requires rcu but for accuracy it also requires irq_enter() (tracepoints record the irq context), thus, the tracepoint interrupt handler should be calling irq_enter() and not rcu_irq_enter() (irq_enter() calls rcu_irq_enter()). So, add irq_enter/exit() to smp_trace_reschedule_interrupt() with common pre/post processing functions, smp_entering_irq() and exiting_irq() (exiting_irq() calls just irq_exit() in arch/x86/include/asm/apic.h), because these can be shared among reschedule, call_function, and call_function_single vectors. [ 50.720557] Testing event reschedule_exit: [ 50.721349] [ 50.721502] =============================== [ 50.721835] [ INFO: suspicious RCU usage. ] [ 50.722169] 3.10.0-rc6-00004-gcf910e8 #190 Not tainted [ 50.722582] ------------------------------- [ 50.722915] /c/kernel-tests/src/linux/arch/x86/include/asm/trace/irq_vectors.h:50 suspicious rcu_dereference_check() usage! [ 50.723770] [ 50.723770] other info that might help us debug this: [ 50.723770] [ 50.724385] [ 50.724385] RCU used illegally from idle CPU! [ 50.724385] rcu_scheduler_active = 1, debug_locks = 0 [ 50.725232] RCU used illegally from extended quiescent state! [ 50.725690] no locks held by swapper/0/0. [ 50.726010] [ 50.726010] stack backtrace: [...] Signed-off-by: Seiji Aguchi <seiji.agu...@hds.com> Reviewed-by: Steven Rostedt <rost...@goodmis.org> Link: http://lkml.kernel.org/r/51cdcfa3.9080...@hds.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/kernel/smp.c | 29 ++++++++++++++++++----------- 1 file changed, 18 insertions(+), 11 deletions(-) diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c index f4fe0b8..cdaa347 100644 --- a/arch/x86/kernel/smp.c +++ b/arch/x86/kernel/smp.c @@ -265,23 +265,30 @@ void smp_reschedule_interrupt(struct pt_regs *regs) */ } -void smp_trace_reschedule_interrupt(struct pt_regs *regs) +static inline void smp_entering_irq(void) { ack_APIC_irq(); + irq_enter(); +} + +void smp_trace_reschedule_interrupt(struct pt_regs *regs) +{ + /* + * Need to call irq_enter() before calling the trace point. + * __smp_reschedule_interrupt() calls irq_enter/exit() too (in + * scheduler_ipi(). This is OK, since those functions are allowed + * to nest. + */ + smp_entering_irq(); trace_reschedule_entry(RESCHEDULE_VECTOR); __smp_reschedule_interrupt(); trace_reschedule_exit(RESCHEDULE_VECTOR); + exiting_irq(); /* * KVM uses this interrupt to force a cpu out of guest mode */ } -static inline void call_function_entering_irq(void) -{ - ack_APIC_irq(); - irq_enter(); -} - static inline void __smp_call_function_interrupt(void) { generic_smp_call_function_interrupt(); @@ -290,14 +297,14 @@ static inline void __smp_call_function_interrupt(void) void smp_call_function_interrupt(struct pt_regs *regs) { - call_function_entering_irq(); + smp_entering_irq(); __smp_call_function_interrupt(); exiting_irq(); } void smp_trace_call_function_interrupt(struct pt_regs *regs) { - call_function_entering_irq(); + smp_entering_irq(); trace_call_function_entry(CALL_FUNCTION_VECTOR); __smp_call_function_interrupt(); trace_call_function_exit(CALL_FUNCTION_VECTOR); @@ -312,14 +319,14 @@ static inline void __smp_call_function_single_interrupt(void) void smp_call_function_single_interrupt(struct pt_regs *regs) { - call_function_entering_irq(); + smp_entering_irq(); __smp_call_function_single_interrupt(); exiting_irq(); } void smp_trace_call_function_single_interrupt(struct pt_regs *regs) { - call_function_entering_irq(); + smp_entering_irq(); trace_call_function_single_entry(CALL_FUNCTION_SINGLE_VECTOR); __smp_call_function_single_interrupt(); trace_call_function_single_exit(CALL_FUNCTION_SINGLE_VECTOR); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
