Messages in this thread | | | Date | Wed, 13 Feb 2019 09:14:50 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH v3 10/10] x86/split_lock: Handle #AC exception for split lock |
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* 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
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