Re: [PATCH] xen: Modify domain_crash() to take a print string

[Jan Beulich <jbeulich@xxxxxxxx>]

On 24.03.2023 00:15, Andrew Cooper wrote:
> On 04/02/2022 12:54 pm, Jan Beulich wrote:
>> On 03.02.2022 14:38, Andrew Cooper wrote:
>>> --- a/xen/arch/x86/domain.c
>>> +++ b/xen/arch/x86/domain.c
>>> @@ -1693,11 +1693,8 @@ static void load_segments(struct vcpu *n)
>>>                   put_guest(uregs->fs,   esp - 5) |
>>>                   put_guest(uregs->es,   esp - 6) |
>>>                   put_guest(uregs->ds,   esp - 7) )
>>> -            {
>>> -                gprintk(XENLOG_ERR,
>>> -                        "error while creating compat failsafe
>>> callback frame\n");
>>> -                domain_crash(n->domain);
>>> -            }
>>> +                domain_crash(n->domain,
>>> +                             "Error creating compat failsafe
>>> callback frame\n");
>>>  
>>>              if ( n->arch.pv.vgc_flags & VGCF_failsafe_disables_events )
>>>                  vcpu_info(n, evtchn_upcall_mask) = 1;
>>> @@ -1732,11 +1729,8 @@ static void load_segments(struct vcpu *n)
>>>               put_guest(uregs->ds,   rsp -  9) |
>>>               put_guest(regs->r11,   rsp - 10) |
>>>               put_guest(regs->rcx,   rsp - 11) )
>>> -        {
>>> -            gprintk(XENLOG_ERR,
>>> -                    "error while creating failsafe callback frame\n");
>>> -            domain_crash(n->domain);
>>> -        }
>>> +            domain_crash(n->domain,
>>> +                         "Error creating failsafe callback frame\n");
>>
>> I assume it wasn't really intended to hide potentially relevant
>> information
>> (the subject vCPU) by this change, which - by way of gprintk() - did get
>> logged before (since we already have n == current at this point)?
> 
> The information is not lost.  __domain_crash() prints current too,
> albeit in a long-winded way.

Oh, right - n == current guarantees the middle path to be taken there.
Considering the other sub-thread also ended up okay-ish:
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Jan