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SubjectRE: [PATCH 2/4] x86/bus_lock: Handle warn and fatal in #DB for bus lock
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Hi, Peter,

> On Sun, Nov 08, 2020 at 04:29:16AM +0000, Fenghua Yu wrote:
> > split_lock_detect=
> > #AC for split lock #DB for bus lock
> >
> > off Do nothing Do nothing
> >
> > warn Kernel OOPs Warn once per task and
> > Warn once per task and and continues to run.
> > disable future checking When both features are
> > supported, warn in #DB
> >
> > fatal Kernel OOPs Send SIGBUS to user
> > Send SIGBUS to user
> > When both features are
> > supported, fatal in #AC.
>
> > +void handle_bus_lock(struct pt_regs *regs) {
> > + if (!bld)
> > + return;
> > +
> > + pr_warn_ratelimited("#DB: %s/%d took a bus_lock trap at address:
> 0x%lx\n",
> > + current->comm, current->pid, regs->ip); }
>
> So the Changelog above, and the state_show() below, seem to suggest there
> should be SIGBUS code in #DB, but I'm having trouble spotting it.

You are right. The SIGBUS is missing here. Somehow my tests didn't capture the issue.

I will add:
+ force_sig_fault(SIGBUS, BUS_ADRALN, NULL);
to send SIGBUS in fatal case for #DB bus lock.

Thank you very much for your review!

-Fenghua

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