| RCU used illegally from idle CPU! | rcu_scheduler_active = 1, debug_locks = 0 | RCU used illegally from extended quiescent state! | no locks held by swapper/1/0. | | [<ffffffff9d492b95>] do_trace_write_msr+0x135/0x140 | [<ffffffff9d06f860>] native_write_msr+0x20/0x30 | [<ffffffff9d065fad>] native_apic_msr_eoi_write+0x1d/0x30 | [<ffffffff9d05bd1d>] smp_reschedule_interrupt+0x1d/0x30 | [<ffffffff9d8daec6>] reschedule_interrupt+0x96/0xa0
Reschedule interrupt may be called in cpu idle state. This causes lockdep check warning above. As Peterz pointed out: | The thing is, many many smp_reschedule_interrupt() invocations don't | actually execute anything much at all and are only send to tickle the | return to user path (which does the actual preemption). | | Having to do the whole irq_enter/irq_exit dance just for this unlikely | debug case totally blows. This patchset adds x2apic write eoi msr notrace to avoid the debug codes splash and reverts irq_enter/irq_exit dance to avoid to make a very frequent interrupt slower because of debug code. v5 -> v6: * split the patch * don't duplicate the inline asm v4 -> v5: * add notrace mark v3 -> v4: * add notrace mark v2 -> v3: * revert irq_enter/irq_exit() since it is merged v1 -> v2: * add write msr notrace to avoid debug codes splash instead of slowdown a very frequent interrupt Wanpeng Li (2): x86/msr: Add write msr notrace x86/apic: x2apic write eoi msr notrace arch/x86/include/asm/apic.h | 3 ++- arch/x86/include/asm/msr.h | 14 +++++++++++++- arch/x86/kernel/apic/apic.c | 1 + arch/x86/kernel/kvm.c | 4 ++-- arch/x86/kernel/smp.c | 2 -- 5 files changed, 18 insertions(+), 6 deletions(-) -- 1.9.1
