From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
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 22:29:44 +0300 [thread overview]
Message-ID: <20200122192944.GL2437@uranus> (raw)
In-Reply-To: <99b572a5-6a98-d22a-01f1-8bab60e96155@intel.com>
On Wed, Jan 22, 2020 at 11:09:47AM -0800, Dave Hansen wrote:
> 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.
OK, I don't mind leaving just WARN_ON_ONCE.
>
> It's not a huge chance, but I've certainly fat-fingered my share of
> off-by-one bugs.
Heh :)
next prev parent reply other threads:[~2020-01-22 19:29 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
2020-01-22 19:29 ` Cyrill Gorcunov [this message]
2020-02-24 19:38 ` [tip: x86/fpu] x86/pkeys: Add " tip-bot2 for Dave Hansen
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