From: Dave Hansen <dave.hansen@intel.com>
To: Cyrill Gorcunov <gorcunov@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, alex.shi@linux.alibaba.com,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
hpa@zytor.com, x86@kernel.org, bigeasy@linutronix.de,
pankaj.laxminarayan.bharadiya@intel.com,
aubrey.li@linux.intel.com
Subject: Re: [PATCH] x86/pkeys: add check for pkey "overflow"
Date: Wed, 22 Jan 2020 11:09:47 -0800 [thread overview]
Message-ID: <99b572a5-6a98-d22a-01f1-8bab60e96155@intel.com> (raw)
In-Reply-To: <20200122185111.GK2437@uranus>
On 1/22/20 10:51 AM, Cyrill Gorcunov wrote:
>> + /*
>> + * This code should only be called with valid 'pkey'
>> + * values originating from in-kernel users. Complain
>> + * if a bad value is observed.
>> + */
>> + WARN_ON_ONCE(pkey >= arch_max_pkey());
> Should not we rather abort this operation and exit with EINVAL
> or something similar instead of calling wrmsr with overflowed
> value? IOW,
>
> if (pkey >= arch_max_pkey()) {
> WARN_ON_ONCE(1);
> return -EINVAL;
> }
I don't feel strongly about it. The reason I didn't do that is to
minimize the chance that this would cause any functional regression.
It's not a huge chance, but I've certainly fat-fingered my share of
off-by-one bugs.
next prev parent reply other threads:[~2020-01-22 19:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-22 16:53 Dave Hansen
2020-01-22 18:51 ` Cyrill Gorcunov
2020-01-22 19:09 ` Dave Hansen [this message]
2020-01-22 19:29 ` Cyrill Gorcunov
2020-02-24 19:38 ` [tip: x86/fpu] x86/pkeys: Add " tip-bot2 for Dave Hansen
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