* Laszlo Ersek ([email protected]) wrote: > On 01/23/17 16:49, Kevin O'Connor wrote: > > On Mon, Jan 23, 2017 at 11:11:02AM +0100, Laszlo Ersek wrote: > >> On 01/20/17 20:39, Dr. David Alan Gilbert wrote: > >>> * Kevin O'Connor ([email protected]) wrote: > >>>> On Fri, Jan 20, 2017 at 06:40:44PM +0000, Dr. David Alan Gilbert wrote: > >>>>> Hi, > >>>>> I turned the debug level up to 4 on our smaller (128k) ROM downstream > >>>>> build and seem to have hit a case where it's been layed out so that the > >>>>> 'ExtraStack' is at the same location as some code (display_uuid) which > >>>>> was causing some very random behaviour; > > [...] > >> Would this be consistent with a stack overflow? > >> > >> See commit 46b82624c95b951e8825fab117d9352faeae0ec8. Perhaps > >> BUILD_EXTRA_STACK_SIZE (2KB) is too small now? > > > > The ExtraStack isn't used at the point Dave reports the problem - > > display_uuid() is part of the init phase and that happens on the main > > "post" stack. > > > > [...] > >> (This is based off 1.9.1) > > > > I missed that earlier - there were some important fixes post 1.9.1 wrt > > reboots. Commits b837e68d / a48f602c2 could explain the issue. I'd > > make sure the issue is still present on the latest version. > > That's a very promising hunch -- b837e68d explicitly mentions "reboot > loop" in the subject. It seems that Dave didn't mention any RHBZ numbers > in his email, but we have two somewhat similar bug reports (which I hope > share a root cause) and the second report triggers the issue with a > reboot loop specifically. > > https://bugzilla.redhat.com/show_bug.cgi?id=1411275 > https://bugzilla.redhat.com/show_bug.cgi?id=1382906 > > (Apologies that the 2nd RHBZ is not public; it's currently filed for the > RH kernel, and those BZs default to private. :/) > > CC'ing DavidH too, for RHBZ#1382906.
Yeh, it's looking promising; I've done a build with low debug that survived for 50+ reboots and turned my debug on and it's going for 20 so far, so that's pretty good. However, reading the commits I'm a little confused. I don't seem to have hit any cases where it's taken the shutdown case after failing to reboot; so it's not that path. My reboots in this case are always guest triggered, so they're not very early reboots. One comment in there is: + // Some old versions of KVM don't store a pristine copy of the + // BIOS in high memory. Try to shutdown the machine instead. do you have a definition of 'old'; in this case it's a new-ish qemu on our downstream (older) kernel but it's got fairly new kvm bits in, but the qemu is configured in our rhel6 compatibility mode - so hmm. Dave (With any luck this post will act as a jinx to wake up any sleeping bugs that make me think it's OK....) > Thank you! > Laszlo > -- Dr. David Alan Gilbert / [email protected] / Manchester, UK _______________________________________________ SeaBIOS mailing list [email protected] https://www.coreboot.org/mailman/listinfo/seabios
