suspicious RCU usage. (TLB flush tracepoints)

From: Dave Jones
Date: Wed Aug 06 2014 - 14:18:21 EST


===============================
[ INFO: suspicious RCU usage. ]
3.16.0+ #34 Not tainted
-------------------------------
include/trace/events/tlb.h:35 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/1/0.

stack backtrace:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.16.0+ #34
0000000000000001 e7d0f46a57e60fc7 ffff880243357db0 ffffffff8a7f1e37
ffff880243360000 ffff880243357de0 ffffffff8a0cc6c5 ffff8801753693f8
ffff88023e2e2a40 0000000000000001 ffff88023e2e2a40 ffff880243357e10
Call Trace:
[<ffffffff8a7f1e37>] dump_stack+0x4e/0x7a
[<ffffffff8a0cc6c5>] lockdep_rcu_suspicious+0xd5/0x110
[<ffffffff8a049f05>] leave_mm+0x1a5/0x200
[<ffffffff8a3ec8df>] intel_idle+0x16f/0x190
[<ffffffff8a6623da>] cpuidle_enter_state+0x3a/0xd0
[<ffffffff8a662557>] cpuidle_enter+0x17/0x20
[<ffffffff8a0c719c>] cpu_startup_entry+0x43c/0x800
[<ffffffff8a03232d>] start_secondary+0x29d/0x3b0


Looks like this came from the addition of trace points in d17d8f9de

Dave

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