From: tip-bot for Dave Jones <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: ak@linux.intel.com, linux-kernel@vger.kernel.org, hpa@zytor.com,
tglx@linutronix.de, davej@codemonkey.org.uk, mingo@kernel.org
Subject: [tip:x86/urgent] x86/apic: Fix suspicious RCU usage in smp_trace_call_function_interrupt()
Date: Fri, 18 Mar 2016 06:54:35 -0700 [thread overview]
Message-ID: <tip-7834c10313fb823e538f2772be78edcdeed2e6e3@git.kernel.org> (raw)
In-Reply-To: <20160315012054.GA17765@codemonkey.org.uk>
Commit-ID: 7834c10313fb823e538f2772be78edcdeed2e6e3
Gitweb: http://git.kernel.org/tip/7834c10313fb823e538f2772be78edcdeed2e6e3
Author: Dave Jones <davej@codemonkey.org.uk>
AuthorDate: Mon, 14 Mar 2016 21:20:54 -0400
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 18 Mar 2016 14:51:06 +0100
x86/apic: Fix suspicious RCU usage in smp_trace_call_function_interrupt()
Since 4.4, I've been able to trigger this occasionally:
===============================
[ INFO: suspicious RCU usage. ]
4.5.0-rc7-think+ #3 Not tainted
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20160315012054.GA17765@codemonkey.org.uk
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-------------------------------
./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 = 1
RCU used illegally from extended quiescent state!
no locks held by swapper/3/0.
stack backtrace:
CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.5.0-rc7-think+ #3
ffffffff92f821e0 1f3e5c340597d7fc ffff880468e07f10 ffffffff92560c2a
ffff880462145280 0000000000000001 ffff880468e07f40 ffffffff921376a6
ffffffff93665ea0 0000cc7c876d28da 0000000000000005 ffffffff9383dd60
Call Trace:
<IRQ> [<ffffffff92560c2a>] dump_stack+0x67/0x9d
[<ffffffff921376a6>] lockdep_rcu_suspicious+0xe6/0x100
[<ffffffff925ae7a7>] do_trace_write_msr+0x127/0x1a0
[<ffffffff92061c83>] native_apic_msr_eoi_write+0x23/0x30
[<ffffffff92054408>] smp_trace_call_function_interrupt+0x38/0x360
[<ffffffff92d1ca60>] trace_call_function_interrupt+0x90/0xa0
<EOI> [<ffffffff92ac5124>] ? cpuidle_enter_state+0x1b4/0x520
Move the entering_irq() call before ack_APIC_irq(), because entering_irq()
tells the RCU susbstems to end the extended quiescent state, so that the
following trace call in ack_APIC_irq() works correctly.
Suggested-by: Andi Kleen <ak@linux.intel.com>
Fixes: 4787c368a9bc "x86/tracing: Add irq_enter/exit() in smp_trace_reschedule_interrupt()"
Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
---
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 0899cfc..98f25bb 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -643,8 +643,8 @@ static inline void entering_irq(void)
static inline void entering_ack_irq(void)
{
- ack_APIC_irq();
entering_irq();
+ ack_APIC_irq();
}
static inline void ipi_entering_ack_irq(void)
prev parent reply other threads:[~2016-03-18 13:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-15 1:20 Fix suspicious RCU usage in msr tracing Dave Jones
2016-03-15 16:39 ` Andi Kleen
2016-03-18 13:54 ` tip-bot for Dave Jones [this message]
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