On 02/08/2018 08:17 PM, Dmitry Vyukov wrote: > On Thu, Feb 8, 2018 at 5:23 PM, Andrey Ryabinin <aryabi...@virtuozzo.com> > wrote: >> >> >> On 02/08/2018 07:18 PM, Jan Kara wrote: >> >>>> By "full kernel crashdump" you mean kdump thing, or something else? >>> >>> Yes, the kdump thing (for KVM guest you can grab the memory dump also from >>> the host in a simplier way and it should be usable with the crash utility >>> AFAIK). >>> >> >> In QEMU monitor 'dump-guest-memory' command: >> >> (qemu) help dump-guest-memory >> dump-guest-memory [-p] [-d] [-z|-l|-s] filename [begin length] -- dump guest >> memory into file 'filename'. >> -p: do paging to get guest's memory mapping. >> -d: return immediately (do not wait for completion). >> -z: dump in kdump-compressed format, with zlib >> compression. >> -l: dump in kdump-compressed format, with lzo >> compression. >> -s: dump in kdump-compressed format, with snappy >> compression. >> begin: the starting physical address. >> length: the memory size, in bytes > > > Nice! > Do you know straight away if it's scriptable/automatable? Or do I just > send some magic sequence of bytes representing ^A+C, > dump-guest-memory, \n to stdin pipe? >
I wouldn't do it via stdin. You can setup monitor on any chardev you like and send command there when you know that guest paniced. Look for -mon and -chardev qemu options. > Unfortunately, syzbot uses GCE VMs for testing, and there does not > seem to be such feature on GCE... > Well, you still have kdump.