summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/smp.c
diff options
context:
space:
mode:
authorSeiji Aguchi <seiji.aguchi@hds.com>2013-06-28 14:02:11 -0400
committerIngo Molnar <mingo@kernel.org>2013-07-02 09:52:31 +0200
commit4787c368a9bca39e173d702389ee2eaf0520abc1 (patch)
tree4c195c5ca8147b5924f1dbd3cfc069061dafe53d /arch/x86/kernel/smp.c
parent5236eb968ec21c693d463d0494e39b00c1bc174d (diff)
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.aguchi@hds.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/51CDCFA3.9080101@hds.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/smp.c')
-rw-r--r--arch/x86/kernel/smp.c29
1 files changed, 18 insertions, 11 deletions
diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index f4fe0b8879e..cdaa347dfca 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);