Commit-ID: 1ec6ec14a2943f6f611fc1d5fb2d4eaa85bd9d72 Gitweb: http://git.kernel.org/tip/1ec6ec14a2943f6f611fc1d5fb2d4eaa85bd9d72 Author: Wanpeng Li <kernel...@gmail.com> AuthorDate: Fri, 14 Oct 2016 09:48:53 +0800 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Fri, 14 Oct 2016 14:14:20 +0200
x86/smp: Add irq_enter/exit() in smp_reschedule_interrupt() =============================== [ INFO: suspicious RCU usage. ] 4.8.0+ #24 Not tainted ------------------------------- ./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 = 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. Add irq_enter/exit() in smp_reschedule_interrupt(), irq_enter() tells the RCU subsystems to end the extended quiescent state, so the following trace call in ack_APIC_irq() works correctly. Signed-off-by: Wanpeng Li <wanpeng...@hotmail.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Mike Galbraith <efa...@gmx.de> Link: http://lkml.kernel.org/r/1476409733-5133-1-git-send-email-wanpeng...@hotmail.com Signed-off-by: Thomas Gleixner <t...@linutronix.de> --- arch/x86/kernel/smp.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c index 658777c..ac2ee87 100644 --- a/arch/x86/kernel/smp.c +++ b/arch/x86/kernel/smp.c @@ -259,8 +259,10 @@ static inline void __smp_reschedule_interrupt(void) __visible void smp_reschedule_interrupt(struct pt_regs *regs) { + irq_enter(); ack_APIC_irq(); __smp_reschedule_interrupt(); + irq_exit(); /* * KVM uses this interrupt to force a cpu out of guest mode */
