Re: [PATCH] s390x/pv: Retry ioctls on -EINTR

[Christian Borntraeger]

>> I fail to see where that is triggered in the kernel.
>>
>> t480s: ~/git/linux/arch/s390/kvm (HEAD losgelöst bei next/master) $ git
>> grep "EINTR"
>> kvm-s390.c:     if (exit_reason == -EINTR) {
>> kvm-s390.c:             return -EINTR;
>> kvm-s390.c:             rc = -EINTR;
>> vsie.c: if (rc == -EINTR) {
>>
>>
>> Can you help me out? Is that documented?
> 
> It is related to the kernel patch.
> ksm_madvise->unmerge_ksm_pages has
> 
>                 if (signal_pending(current))
>                         err = -ERESTARTSYS;
> 
> 
> entry.S will retranslate ERESTARTSYS into -EINTR. 
> 

In the end both patches fixes an odd-ball case. Marc had a test running
that in parallel started guests and randomly killing QEMUs with pkill.
The QEMUs did end with 

qemu-system-s390x: KVM PV command 0 (KVM_PV_ENABLE) failed: header rc 0 rrc 0 
IOCTL rc: -12

instead of

qemu-system-s390x: terminating on signal 15 from pid 26495 (pkill)