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From: Thomas Gleixner <tglx@linutronix.de>
To: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Cc: Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
	thomas.lendacky@amd.com
Subject: Re: [5.0.0 rc3 BUG] possible irq lock inversion dependency detected
Date: Sun, 14 Apr 2019 19:51:06 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.21.1904141948200.4917@nanos.tec.linutronix.de> (raw)
In-Reply-To: <CABXGCsMcS+H9jxEotmM3u8F28zhPobvT3+Hd_iWstFQN744v6Q@mail.gmail.com>

Hi,

On Sun, 14 Apr 2019, Mikhail Gavrilov wrote:

> This bug is still present in 5.1 rc4
> Why no one answered me?

Because mails fall through the cracks occasionally.

Does the patch below cure your problem?

Thanks,

	tglx

8<------------------
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -426,6 +426,8 @@ static __always_inline void __speculatio
 	u64 msr = x86_spec_ctrl_base;
 	bool updmsr = false;
 
+	lockdep_assert_irqs_disabled();
+
 	/*
 	 * If TIF_SSBD is different, select the proper mitigation
 	 * method. Note that if SSBD mitigation is disabled or permanentely
@@ -477,10 +479,12 @@ static unsigned long speculation_ctrl_up
 
 void speculation_ctrl_update(unsigned long tif)
 {
+	unsigned long flags;
+
 	/* Forced update. Make sure all relevant TIF flags are different */
-	preempt_disable();
+	local_irq_save(flags);
 	__speculation_ctrl_update(~tif, tif);
-	preempt_enable();
+	local_irq_restore(flags);
 }
 
 /* Called from seccomp/prctl update */

  reply	other threads:[~2019-04-14 17:51 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-02 18:33 [5.0.0 rc3 BUG] possible irq lock inversion dependency detected Mikhail Gavrilov
2019-04-14 17:33 ` Mikhail Gavrilov
2019-04-14 17:51   ` Thomas Gleixner [this message]
2019-04-14 20:07     ` Mikhail Gavrilov
2019-04-18 16:52       ` Mikhail Gavrilov
2019-04-18 19:17         ` Thomas Gleixner
2019-04-14 21:10     ` [tip:x86/urgent] x86/speculation: Prevent deadlock on ssb_state::lock tip-bot for Thomas Gleixner
     [not found]       ` <20190415130916.BAC1020684@mail.kernel.org>
2019-04-15 16:13         ` Thomas Gleixner

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