summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorDave Jones <davej@codemonkey.org.uk>2016-03-15 01:20:54 (GMT)
committerThomas Gleixner <tglx@linutronix.de>2016-03-18 13:51:06 (GMT)
commit7834c10313fb823e538f2772be78edcdeed2e6e3 (patch)
tree2d15fa4a3375ff6b3eac6bb7f252a93cf4b30cb8
parentc29016cf41fe9fa994a5ecca607cf5f1cd98801e (diff)
downloadlinux-7834c10313fb823e538f2772be78edcdeed2e6e3.tar.xz
x86/apic: Fix suspicious RCU usage in smp_trace_call_function_interrupt()
Since 4.4, I've been able to trigger this occasionally: =============================== [ INFO: suspicious RCU usage. ] 4.5.0-rc7-think+ #3 Not tainted Cc: Andi Kleen <ak@linux.intel.com> Link: http://lkml.kernel.org/r/20160315012054.GA17765@codemonkey.org.uk Signed-off-by: Thomas Gleixner <tglx@linutronix.de> ------------------------------- ./arch/x86/include/asm/msr-trace.h:47 suspicious rcu_dereference_check() usage! other info that might help us debug this: RCU used illegally from idle CPU! rcu_scheduler_active = 1, debug_locks = 1 RCU used illegally from extended quiescent state! no locks held by swapper/3/0. stack backtrace: CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.5.0-rc7-think+ #3 ffffffff92f821e0 1f3e5c340597d7fc ffff880468e07f10 ffffffff92560c2a ffff880462145280 0000000000000001 ffff880468e07f40 ffffffff921376a6 ffffffff93665ea0 0000cc7c876d28da 0000000000000005 ffffffff9383dd60 Call Trace: <IRQ> [<ffffffff92560c2a>] dump_stack+0x67/0x9d [<ffffffff921376a6>] lockdep_rcu_suspicious+0xe6/0x100 [<ffffffff925ae7a7>] do_trace_write_msr+0x127/0x1a0 [<ffffffff92061c83>] native_apic_msr_eoi_write+0x23/0x30 [<ffffffff92054408>] smp_trace_call_function_interrupt+0x38/0x360 [<ffffffff92d1ca60>] trace_call_function_interrupt+0x90/0xa0 <EOI> [<ffffffff92ac5124>] ? cpuidle_enter_state+0x1b4/0x520 Move the entering_irq() call before ack_APIC_irq(), because entering_irq() tells the RCU susbstems to end the extended quiescent state, so that the following trace call in ack_APIC_irq() works correctly. Suggested-by: Andi Kleen <ak@linux.intel.com> Fixes: 4787c368a9bc "x86/tracing: Add irq_enter/exit() in smp_trace_reschedule_interrupt()" Signed-off-by: Dave Jones <davej@codemonkey.org.uk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org
-rw-r--r--arch/x86/include/asm/apic.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 0899cfc..98f25bb 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -643,8 +643,8 @@ static inline void entering_irq(void)
static inline void entering_ack_irq(void)
{
- ack_APIC_irq();
entering_irq();
+ ack_APIC_irq();
}
static inline void ipi_entering_ack_irq(void)