From: Wanpeng Li <kernellwp@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Wanpeng Li <wanpeng.li@hotmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>
Subject: [PATCH] x86/apic: Fix suspicious RCU usage in smp_trace_call_function_interrupt
Date: Thu, 15 Sep 2016 14:22:00 +0800 [thread overview]
Message-ID: <1473920520-12220-1-git-send-email-wanpeng.li@hotmail.com> (raw)
From: Wanpeng Li <wanpeng.li@hotmail.com>
===============================
[ INFO: suspicious RCU usage. ]
4.8.0-rc6+ #5 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/2/0.
stack backtrace:
CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.8.0-rc6+ #5
Hardware name: Dell Inc. OptiPlex 7020/0F5C5X, BIOS A03 01/08/2015
0000000000000000 ffff8d1bd6003f10 ffffffff94446949 ffff8d1bd4a68000
0000000000000001 ffff8d1bd6003f40 ffffffff940e9247 ffff8d1bbdfcf3d0
000000000000080b 0000000000000000 0000000000000000 ffff8d1bd6003f70
Call Trace:
<IRQ> [<ffffffff94446949>] dump_stack+0x99/0xd0
[<ffffffff940e9247>] lockdep_rcu_suspicious+0xe7/0x120
[<ffffffff9448e0d5>] do_trace_write_msr+0x135/0x140
[<ffffffff9406e750>] native_write_msr+0x20/0x30
[<ffffffff9406503d>] native_apic_msr_eoi_write+0x1d/0x30
[<ffffffff9405b17e>] smp_trace_call_function_interrupt+0x1e/0x270
[<ffffffff948cb1d6>] trace_call_function_interrupt+0x96/0xa0
<EOI> [<ffffffff947200f4>] ? cpuidle_enter_state+0xe4/0x360
[<ffffffff947200df>] ? cpuidle_enter_state+0xcf/0x360
[<ffffffff947203a7>] cpuidle_enter+0x17/0x20
[<ffffffff940df008>] cpu_startup_entry+0x338/0x4d0
[<ffffffff9405bfc4>] start_secondary+0x154/0x180
This can be reproduced readily by running ftrace test case of kselftest.
Move the irq_enter() call before ack_APIC_irq(), because irq_enter()
tells the RCU susbstems to end the extended quiescent state, so that the
following trace call in ack_APIC_irq() works correctly.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
---
arch/x86/include/asm/apic.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 1243577..71c1fe2 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -650,8 +650,8 @@ static inline void entering_ack_irq(void)
static inline void ipi_entering_ack_irq(void)
{
- ack_APIC_irq();
irq_enter();
+ ack_APIC_irq();
}
static inline void exiting_irq(void)
--
1.9.1
next reply other threads:[~2016-09-15 6:22 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-15 6:22 Wanpeng Li [this message]
2016-09-15 8:58 ` Thomas Gleixner
2016-09-18 8:32 ` Wanpeng Li
2016-09-18 11:35 ` Wanpeng Li
2016-09-19 8:10 ` Peter Zijlstra
2016-10-12 11:07 ` Wanpeng Li
2016-10-12 13:17 ` Thomas Gleixner
2016-10-13 12:19 ` Wanpeng Li
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