From: Borislav Petkov <bp@alien8.de>
To: Marco Elver <elver@google.com>, Qian Cai <cai@lca.pw>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
the arch/x86 maintainers <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH -next] x86/mm/pat: silence a data race in cpa_4k_install
Date: Tue, 21 Jan 2020 16:45:28 +0100 [thread overview]
Message-ID: <20200121154528.GK7808@zn.tnic> (raw)
In-Reply-To: <CANpmjNO7mTEMc6pvpVVXdu2r6cMg_N8QkRffEHHG-WNFXE4CjA@mail.gmail.com>
On Tue, Jan 21, 2020 at 04:36:49PM +0100, Marco Elver wrote:
> Isn't the intent "x86/mm/pat: Mark intentional data race" ? The fact
> that KCSAN no longer shows the warning is a side-effect. At least
> that's how I see it.
Perhaps because you've been dealing with KCSAN for so long. :-)
The main angle here, IMO, is that this "fix" is being done solely for
KCSAN. Or is there another reason to "fix" intentional data races? At
least I don't see one. And the text says
"This will generate a lot of noise on a debug kernel with
debug_pagealloc with KCSAN enabled which could render the system
unusable."
So yes, I think it should say something about making KCSAN happy.
Oh, and while at it I'd prefer it if it did the __no_kcsan function
annotation instead of the data_race() thing.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2020-01-21 15:45 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-21 15:15 [PATCH -next] x86/mm/pat: silence a data race in cpa_4k_install Qian Cai
2020-01-21 15:19 ` Marco Elver
2020-01-21 15:28 ` Borislav Petkov
2020-01-21 15:33 ` Qian Cai
2020-01-21 15:36 ` Marco Elver
2020-01-21 15:45 ` Borislav Petkov [this message]
2020-01-21 20:21 ` Qian Cai
2020-01-21 22:18 ` Borislav Petkov
2020-01-21 23:30 ` Marco Elver
2020-01-22 0:34 ` Qian Cai
2020-01-22 8:46 ` Peter Zijlstra
2020-01-23 2:15 ` Qian Cai
2020-01-23 8:16 ` Borislav Petkov
-- strict thread matches above, loose matches on Subject: below --
2020-01-21 15:50 Qian Cai
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