linux-kernel - Re: [patch V2 07/17] x86/entry/64: Remove redundant interrupt disable

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Message-ID: <20191023220618.qsmog2k5oaagj27v@treble>
Date:   Wed, 23 Oct 2019 17:06:18 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        Will Deacon <will@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        linux-arch@...r.kernel.org, Mike Rapoport <rppt@...ux.ibm.com>,
        Miroslav Benes <mbenes@...e.cz>
Subject: Re: [patch V2 07/17] x86/entry/64: Remove redundant interrupt disable

On Wed, Oct 23, 2019 at 02:27:12PM +0200, Thomas Gleixner wrote:
> Now that the trap handlers return with interrupts disabled, the
> unconditional disabling of interrupts in the low level entry code can be
> removed along with the trace calls.
> 
> Add debug checks where appropriate.

This seems a little scary.  Does anybody other than Andy actually run
with CONFIG_DEBUG_ENTRY?  What happens if somebody accidentally leaves
irqs enabled?  How do we know you found all the leaks?

-- 
Josh