x86/smp: Add irq_enter/exit() in smp_reschedule_interrupt()
authorWanpeng Li <kernellwp@gmail.com>
Fri, 14 Oct 2016 01:48:53 +0000 (09:48 +0800)
committerThomas Gleixner <tglx@linutronix.de>
Fri, 14 Oct 2016 12:14:20 +0000 (14:14 +0200)
commit1ec6ec14a2943f6f611fc1d5fb2d4eaa85bd9d72
tree3ada863d9c60928176cd62b5b255566497465022
parentd4b05923f579c234137317cdf9a5eb69ddab76d1
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.li@hotmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Link: http://lkml.kernel.org/r/1476409733-5133-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
arch/x86/kernel/smp.c