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Date:   Tue, 1 Nov 2022 09:48:03 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Gaosheng Cui <cuigaosheng1@huawei.com>
Cc:     tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
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        mario.limonciello@amd.com, tony.luck@intel.com,
        andrew.cooper3@citrix.com, pawan.kumar.gupta@linux.intel.com,
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        chenyi.qiang@intel.com, rafael.j.wysocki@intel.com,
        paulmck@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/cpu: replacing the open-coded shift with BIT(x)
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On Tue, Nov 01, 2022 at 02:09:45PM +0800, Gaosheng Cui wrote:
> Replace the open-coded shift with BIT(x) for x86_power to make the
> code a bit more self-documenting, and we will get a UBSAN issue in
> arch/x86/kernel/cpu/proc.c, fix it.
> 
> The UBSAN warning calltrace like below:
> 
> UBSAN: shift-out-of-bounds in arch/x86/kernel/cpu/proc.c:138:25
> left shift of 1 by 31 places cannot be represented in type 'int'

Same as to the other case; UBSAN is broken garbage, stop quoting it.