Messages in this thread | | | Date | Fri, 22 Nov 2019 21:23:12 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v10 6/6] x86/split_lock: Enable split lock detection by kernel parameter |
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On Fri, Nov 22, 2019 at 09:22:46AM -0800, Luck, Tony wrote: > On Fri, Nov 22, 2019 at 04:27:15PM +0100, Peter Zijlstra wrote: > > +void handle_user_split_lock(struct pt_regs *regs, long error_code) > > +{ > > + if (sld_state == sld_fatal) > > + return false; > > + > > + pr_alert("#AC: %s/%d took a split_lock trap at address: 0x%lx\n", > > + current->comm, current->pid, regs->ip); > > + > > + __sld_set_msr(false); > > + set_tsk_thread_flag(current, TIF_CLD); > > + return true; > > +} > > I think you need an extra check in here. While a #AC in the kernel > is an indication of a split lock. A user might have enabled alignment > checking and so this #AC might not be from a split lock. > > I think the extra code if just to change that first test to: > > if ((regs->eflags & X86_EFLAGS_AC) || sld_fatal)
Indeed.
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