Stuart Henderson <s...@spacehopper.org> writes:
> On 2017/10/21 14:52, Tim Stewart wrote:
>> Stuart Henderson <s...@spacehopper.org> writes:
>>
>> > On 2017/10/21 12:04, Tim Stewart wrote:
>> >> *49727 296965 0 0 7 0x14200 crynlk
>> >
>> > aha, it was that one. Try this diff on top.
>> >
>> > Index: fpu.c
>> > ===================================================================
>> > RCS file: /cvs/src/sys/arch/amd64/amd64/fpu.c,v
>> > retrieving revision 1.38
>> > diff -u -p -r1.38 fpu.c
>> > --- fpu.c 14 Oct 2017 04:44:43 -0000 1.38
>> > +++ fpu.c 21 Oct 2017 16:16:14 -0000
>> > @@ -347,7 +347,7 @@ void
>> > fpu_kernel_enter(void)
>> > {
>> > struct cpu_info *ci = curcpu();
>> > - uint32_t cw;
>> > + struct savefpu *sfp;
>> > int s;
>> >
>> > /*
>> > @@ -376,10 +376,11 @@ fpu_kernel_enter(void)
>> >
>> > /* Initialize the FPU */
>> > fninit();
>> > - cw = __INITIAL_NPXCW__;
>> > - fldcw(&cw);
>> > - cw = __INITIAL_MXCSR__;
>> > - ldmxcsr(&cw);
>> > + sfp = &proc0.p_addr->u_pcb.pcb_savefpu;
>> > + memset(&sfp->fp_fxsave, 0, sizeof(sfp->fp_fxsave));
>> > + sfp->fp_fxsave.fx_fcw = __INITIAL_NPXCW__;
>> > + sfp->fp_fxsave.fx_mxcsr = __INITIAL_MXCSR__;
>> > + fxrstor(&sfp->fp_fxsave);
>> > }
>> >
>> > void
>>
>> I've been running with this additional patch for a couple of hours and
>> the hang has not reappeared. I'll keep the system active and confirm
>> thta everything looks good tomorrow.
>>
>> I swear I've seen this patch before on a list but can't find the
>> original. Can someone give me or point me at some context, so I know
>> what I've just done? :)
>
> Diff is from mikeb. It initializes the fpu more completely, we suspect
> something in the userland state wasn't getting cleared when entering the
> kernel. I saw some problems with aes-ni up after the "Correctly handle
> exceptions when restoring an invalid FPU context" commit. (aes-ni uses
> floating point registers).
I see. So I'm guessing that an "unlocked" IPsec more likely to hit this
bug because it's using AES-NI outside of KERNEL_LOCK() now? Am I close?
-TimS
--
Tim Stewart
-----------
Mail: t...@stoo.org
Matrix: @tim:stoo.org
