From: Ingo Molnar <mingo@kernel.org>
To: Fenghua Yu <fenghua.yu@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, H Peter Anvin <hpa@zytor.com>,
Dave Hansen <dave.hansen@intel.com>,
Ashok Raj <ashok.raj@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Michael Chan <michael.chan@broadcom.com>,
Ravi V Shankar <ravi.v.shankar@intel.com>,
Ricardo Neri <ricardo.neri@intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>
Subject: Re: [PATCH v3 10/10] x86/split_lock: Handle #AC exception for split lock
Date: Wed, 13 Feb 2019 09:14:50 +0100 [thread overview]
Message-ID: <20190213081450.GA53242@gmail.com> (raw)
In-Reply-To: <20190211181013.GA103371@romley-ivt3.sc.intel.com>
* Fenghua Yu <fenghua.yu@intel.com> wrote:
> On Mon, Feb 11, 2019 at 11:53:39AM +0100, Ingo Molnar wrote:
> > > + do_trap(trapnr, signr, str, regs, error_code, BUS_ADRALN, NULL);
> > > + }
> > > +}
> >
> > Is there any experience with how frequently this signal is killing
> > user-space processes on a modern distro? Any expectation of how frequent
> > such SIGBUS task terminations are going to be in the field?
>
> We did pretty intensive testing internally (zero day tests, many engineers
> and testers use the patches in their dailly work, etc). So far I'm not
> aware of any user space process hiting split lock issue. I guess GCC or
> other compilers takes care of the issue already. Inline assembly code may
> hit the issue if code is not right, but there are fewer inline assembly
> code in user space.
>
> So far we only find two kernel split lock issues and fix them in the first
> two patches in this patch set. We also find one BIOS split lock issue
> internally which has been fixed in production BIOS.
>
> Thanks.
Ok, still, for binary compatibility's sake, could you please add a sysctl
knob (root-only, etc.) and a kernel boot parameter that disables this
check?
Looks good otherwise.
Thanks,
Ingo
next prev parent reply other threads:[~2019-02-13 8:14 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-02 5:14 [PATCH v3 00/10] x86/split_lock: Enable #AC exception for split locked accesses Fenghua Yu
2019-02-02 5:14 ` [PATCH v3 01/10] x86/common: Align cpu_caps_cleared and cpu_caps_set to unsigned long Fenghua Yu
2019-02-02 5:14 ` [PATCH v3 02/10] drivers/net/b44: Align pwol_mask to unsigned long for better performance Fenghua Yu
2019-02-02 5:14 ` [PATCH v3 03/10] wlcore: Align reg_ch_conf_pending and tmp_ch_bitmap " Fenghua Yu
2019-02-02 5:14 ` [PATCH v3 04/10] x86/split_lock: Align x86_capability to unsigned long to avoid split locked access Fenghua Yu
2019-02-02 5:14 ` [PATCH v3 05/10] x86/clearcpuid: Support multiple clearcpuid options Fenghua Yu
2019-02-02 5:14 ` [PATCH v3 06/10] x86/clearcpuid: Support feature flag string in kernel option clearcpuid Fenghua Yu
2019-02-02 5:14 ` [PATCH v3 07/10] Change document for " Fenghua Yu
2019-02-02 5:14 ` [PATCH v3 08/10] x86/setcpuid: Add kernel option setcpuid Fenghua Yu
2019-02-04 17:49 ` Thomas Gleixner
2019-02-04 19:05 ` Dave Hansen
2019-02-04 19:57 ` Borislav Petkov
2019-02-04 20:46 ` Dave Hansen
2019-02-04 21:40 ` Borislav Petkov
2019-02-04 22:14 ` Fenghua Yu
2019-02-05 6:10 ` Borislav Petkov
2019-02-04 23:24 ` Dave Hansen
2019-02-05 6:18 ` Borislav Petkov
2019-02-05 16:46 ` Dave Hansen
2019-02-05 17:09 ` Peter Zijlstra
2019-02-05 8:57 ` Peter Zijlstra
2019-02-05 13:15 ` Peter Zijlstra
2019-02-05 8:48 ` Peter Zijlstra
2019-02-05 15:19 ` Dave Hansen
2019-02-05 15:43 ` Borislav Petkov
2019-02-05 18:26 ` Fenghua Yu
2019-02-05 17:04 ` Peter Zijlstra
2019-02-10 19:20 ` Thomas Gleixner
2019-02-11 19:16 ` Fenghua Yu
2019-02-12 13:37 ` Peter Zijlstra
2019-02-12 13:51 ` Thomas Gleixner
2019-02-12 16:48 ` Peter Zijlstra
2019-02-12 16:50 ` Dave Hansen
2019-02-12 17:52 ` Yu, Fenghua
2019-02-04 21:09 ` Fenghua Yu
2019-02-05 8:51 ` Peter Zijlstra
2019-02-05 15:21 ` Dave Hansen
2019-02-05 15:34 ` Peter Zijlstra
2019-02-02 5:14 ` [PATCH v3 09/10] x86/split_lock: Define #AC for split lock feature Fenghua Yu
2019-02-04 18:41 ` Dave Hansen
2019-02-04 18:45 ` Fenghua Yu
2019-02-04 19:00 ` Dave Hansen
2019-02-04 19:03 ` Fenghua Yu
2019-02-02 5:14 ` [PATCH v3 10/10] x86/split_lock: Handle #AC exception for split lock Fenghua Yu
2019-02-04 11:00 ` kbuild test robot
2019-02-04 14:43 ` kbuild test robot
2019-02-11 10:53 ` Ingo Molnar
2019-02-11 18:10 ` Fenghua Yu
2019-02-13 8:14 ` Ingo Molnar [this message]
2019-02-13 14:37 ` Yu, Fenghua
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