From: Jiri Olsa <jolsa@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Josh Triplett <josh@joshtriplett.org>,
Andi Kleen <andi@firstfloor.org>,
Jan Stancek <jstancek@redhat.com>
Subject: Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage!
Date: Thu, 23 Feb 2017 13:24:34 +0100 [thread overview]
Message-ID: <20170223122434.GA20127@krava> (raw)
In-Reply-To: <20161121092850.GF3102@twins.programming.kicks-ass.net>
On Mon, Nov 21, 2016 at 10:28:50AM +0100, Peter Zijlstra wrote:
> On Mon, Nov 21, 2016 at 01:53:43AM +0100, Jiri Olsa wrote:
> > hi,
> > Jan hit following output when msr tracepoints are enabled on amd server:
> >
> > [ 91.585653] ===============================
> > [ 91.589840] [ INFO: suspicious RCU usage. ]
> > [ 91.594025] 4.9.0-rc1+ #1 Not tainted
> > [ 91.597691] -------------------------------
> > [ 91.601877] ./arch/x86/include/asm/msr-trace.h:42 suspicious rcu_dereference_check() usage!
> > [ 91.610222]
> > [ 91.610222] other info that might help us debug this:
> > [ 91.610222]
> > [ 91.618224]
> > [ 91.618224] RCU used illegally from idle CPU!
> > [ 91.618224] rcu_scheduler_active = 1, debug_locks = 0
> > [ 91.629081] RCU used illegally from extended quiescent state!
> > [ 91.634820] no locks held by swapper/1/0.
> > [ 91.638832]
> > [ 91.638832] stack backtrace:
> > [ 91.643192] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.9.0-rc1+ #1
> > [ 91.649457] Hardware name: empty empty/S3992, BIOS 'V2.03 ' 05/09/2008
> > [ 91.656159] ffffc900018fbdf8 ffffffff813ed43c ffff88017ede8000 0000000000000001
> > [ 91.663637] ffffc900018fbe28 ffffffff810fdcd7 ffff880233f95dd0 00000000c0010055
> > [ 91.671107] 0000000000000000 0000000000000000 ffffc900018fbe58 ffffffff814297ac
> > [ 91.678560] Call Trace:
> > [ 91.681022] [<ffffffff813ed43c>] dump_stack+0x85/0xc9
> > [ 91.686164] [<ffffffff810fdcd7>] lockdep_rcu_suspicious+0xe7/0x120
> > [ 91.692429] [<ffffffff814297ac>] do_trace_read_msr+0x14c/0x1b0
> > [ 91.698349] [<ffffffff8106ddb2>] native_read_msr+0x32/0x40
> > [ 91.703921] [<ffffffff8103b2be>] amd_e400_idle+0x7e/0x110
> > [ 91.709407] [<ffffffff8103b78f>] arch_cpu_idle+0xf/0x20
> > [ 91.714720] [<ffffffff8181cd33>] default_idle_call+0x23/0x40
> > [ 91.720467] [<ffffffff810f306a>] cpu_startup_entry+0x1da/0x2b0
> > [ 91.726387] [<ffffffff81058b1f>] start_secondary+0x17f/0x1f0
> >
> >
> > it got away with attached change.. but this rcu logic
> > is far beyond me, so it's just wild guess.. ;-)
>
> I think I prefer something like the below, that only annotates the one
> RDMSR in question, instead of all of them.
>
>
> diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
> index 0888a879120f..d6c6aa80675f 100644
> --- a/arch/x86/kernel/process.c
> +++ b/arch/x86/kernel/process.c
> @@ -357,7 +357,7 @@ static void amd_e400_idle(void)
> if (!amd_e400_c1e_detected) {
> u32 lo, hi;
>
> - rdmsr(MSR_K8_INT_PENDING_MSG, lo, hi);
> + RCU_NONIDLE(rdmsr(MSR_K8_INT_PENDING_MSG, lo, hi));
>
> if (lo & K8_INTP_C1E_ACTIVE_MASK) {
> amd_e400_c1e_detected = true;
hum, I might have missed some other solution in discussion,
and can't see this one being pulled in.. should I resend this?
thanks,
jirka
next prev parent reply other threads:[~2017-02-23 12:24 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-21 0:53 [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Jiri Olsa
2016-11-21 9:02 ` Paul E. McKenney
2016-11-21 9:43 ` Peter Zijlstra
2016-11-21 11:00 ` Paul E. McKenney
2016-11-21 9:28 ` Peter Zijlstra
2016-11-21 9:34 ` Jiri Olsa
2016-11-21 9:42 ` Peter Zijlstra
2016-11-21 11:22 ` Jiri Olsa
2016-11-21 11:31 ` Peter Zijlstra
2016-11-21 12:49 ` Jiri Olsa
2016-11-21 12:58 ` Peter Zijlstra
2016-11-21 14:15 ` Steven Rostedt
2016-11-21 14:37 ` Peter Zijlstra
2016-11-21 15:35 ` Borislav Petkov
2016-11-21 15:41 ` Peter Zijlstra
2016-11-21 16:06 ` Borislav Petkov
2016-11-29 13:16 ` Borislav Petkov
2016-11-29 13:59 ` Thomas Gleixner
2016-11-30 8:48 ` Borislav Petkov
2016-11-30 8:54 ` Thomas Gleixner
2016-11-30 9:07 ` Borislav Petkov
2016-11-30 9:14 ` Thomas Gleixner
2016-11-29 14:04 ` Jiri Olsa
2016-11-21 14:20 ` Steven Rostedt
2016-11-21 17:06 ` Andi Kleen
2016-11-21 17:18 ` Peter Zijlstra
2016-11-21 17:45 ` Andi Kleen
2016-11-21 18:01 ` Steven Rostedt
2016-11-21 18:06 ` Andi Kleen
2016-11-21 18:22 ` Steven Rostedt
2016-11-21 18:37 ` Andi Kleen
2016-11-21 19:06 ` Steven Rostedt
2016-11-21 19:15 ` Steven Rostedt
2016-11-21 20:44 ` Andi Kleen
2016-11-22 8:19 ` Paul E. McKenney
2016-11-22 14:39 ` Steven Rostedt
2016-11-22 19:05 ` Andi Kleen
2016-11-24 2:06 ` Steven Rostedt
2016-11-28 21:48 ` Andi Kleen
2016-11-28 22:46 ` Steven Rostedt
2016-11-28 23:10 ` Andi Kleen
2016-11-21 17:55 ` Steven Rostedt
2016-11-21 18:24 ` Steven Rostedt
2016-11-21 20:12 ` Paul E. McKenney
2017-02-23 12:24 ` Jiri Olsa [this message]
2017-02-23 17:11 ` Andi Kleen
2017-02-23 17:28 ` Peter Zijlstra
2017-02-23 17:56 ` Borislav Petkov
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