From: Peter Zijlstra <peterz@infradead.org>
To: Peter Shier <pshier@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
Len Brown <lenb@kernel.org>, Michael Roth <michael.roth@amd.com>,
Alexei Starovoitov <ast@kernel.org>,
Josh Poimboeuf <jpoimboe@kernel.org>,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
Subject: Re: [PATCH v2] intel_idle: avoid tracing MSR writes while idling
Date: Thu, 25 Aug 2022 10:41:01 +0200 [thread overview]
Message-ID: <Ywc1naLthsmxI0cF@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20220824234211.1625026-1-pshier@google.com>
On Wed, Aug 24, 2022 at 04:42:11PM -0700, Peter Shier wrote:
> With commit bf5835bcdb963 ("intel_idle: Disable IBRS during long idle"),
> enabling wrmsr trace with CONFIG_LOCKDEP causes "suspicious
> rcu_dereference_check() usage" warning because do_trace_write_msr does not
> use trace_write_msr_rcuidle.
>
> Change intel_idle_ibrs to use native_wrmsr to avoid tracing
>
> Signed-off-by: Peter Shier <pshier@google.com>
> ---
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> drivers/idle/intel_idle.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
> index 3e101719689a..df129c73786f 100644
> --- a/drivers/idle/intel_idle.c
> +++ b/drivers/idle/intel_idle.c
> @@ -187,12 +187,12 @@ static __cpuidle int intel_idle_ibrs(struct cpuidle_device *dev,
> int ret;
>
> if (smt_active)
> - wrmsrl(MSR_IA32_SPEC_CTRL, 0);
> + native_wrmsr(MSR_IA32_SPEC_CTRL, 0);
>
> ret = __intel_idle(dev, drv, index);
>
> if (smt_active)
> - wrmsrl(MSR_IA32_SPEC_CTRL, spec_ctrl);
> + native_wrmsr(MSR_IA32_SPEC_CTRL, spec_ctrl);
>
> return ret;
> }
> --
next prev parent reply other threads:[~2022-08-25 8:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-24 23:42 [PATCH v2] intel_idle: avoid tracing MSR writes while idling Peter Shier
2022-08-25 8:41 ` Peter Zijlstra [this message]
2022-08-25 11:43 ` Rafael J. Wysocki
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