[Qemu-devel] [Bug 1013241] Re: qemu-system-ppc64 hanging occasionally in disk writes
[Expired for QEMU because there has been no activity for 60 days.] ** Changed in: qemu Status: Incomplete => Expired -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1013241 Title: qemu-system-ppc64 hanging occasionally in disk writes Status in QEMU: Expired Bug description: I found last week that qemu-system-ppc64 (from git) hangs occasionally under load, and I have a reproducer for it now. Unfortunately the reproducer really takes a long time to run -- usually I can get a hang in under 12 hours. Here is the reproducer case: https://lists.fedoraproject.org/pipermail/ppc/2012-June/001698.html Notes: (1) Verified by one other person (other than me). Happens on both ppc64 and x86-64 host. (2) Happens with both Fedora guest kernel 3.3.4-5.fc17.ppc64 and kernel 3.5.0 that I compiled myself. The test case above contains 3.3.4-5. (3) Seems to be a problem in qemu, not the guest. The reason I think this is because I tried to capture a backtrace of the hang using remote gdb, but gdb just hung when trying to connect to qemu (gdb connects fine before the bug happens). (4) Judging by guest messages, appears to be happening when writing to the disk. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1013241/+subscriptions
[Qemu-devel] [Bug 1013241] Re: qemu-system-ppc64 hanging occasionally in disk writes
Looking through old bug tickets... can you still reproduce this issue with the latest version of QEMU? Or could we close this ticket nowadays? ** Changed in: qemu Status: New => Incomplete -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1013241 Title: qemu-system-ppc64 hanging occasionally in disk writes Status in QEMU: Incomplete Bug description: I found last week that qemu-system-ppc64 (from git) hangs occasionally under load, and I have a reproducer for it now. Unfortunately the reproducer really takes a long time to run -- usually I can get a hang in under 12 hours. Here is the reproducer case: https://lists.fedoraproject.org/pipermail/ppc/2012-June/001698.html Notes: (1) Verified by one other person (other than me). Happens on both ppc64 and x86-64 host. (2) Happens with both Fedora guest kernel 3.3.4-5.fc17.ppc64 and kernel 3.5.0 that I compiled myself. The test case above contains 3.3.4-5. (3) Seems to be a problem in qemu, not the guest. The reason I think this is because I tried to capture a backtrace of the hang using remote gdb, but gdb just hung when trying to connect to qemu (gdb connects fine before the bug happens). (4) Judging by guest messages, appears to be happening when writing to the disk. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1013241/+subscriptions
[Qemu-devel] [Bug 1013241] Re: qemu-system-ppc64 hanging occasionally in disk writes
The problem with virtio-scsi is only a single disk shows up: https://bugs.launchpad.net/qemu/+bug/1013691 I've been using guest kernels 3.3.4 and 3.5.0-rc2+ (ie. Linus git), and both behave the same way. -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1013241 Title: qemu-system-ppc64 hanging occasionally in disk writes Status in QEMU: New Bug description: I found last week that qemu-system-ppc64 (from git) hangs occasionally under load, and I have a reproducer for it now. Unfortunately the reproducer really takes a long time to run -- usually I can get a hang in under 12 hours. Here is the reproducer case: https://lists.fedoraproject.org/pipermail/ppc/2012-June/001698.html Notes: (1) Verified by one other person (other than me). Happens on both ppc64 and x86-64 host. (2) Happens with both Fedora guest kernel 3.3.4-5.fc17.ppc64 and kernel 3.5.0 that I compiled myself. The test case above contains 3.3.4-5. (3) Seems to be a problem in qemu, not the guest. The reason I think this is because I tried to capture a backtrace of the hang using remote gdb, but gdb just hung when trying to connect to qemu (gdb connects fine before the bug happens). (4) Judging by guest messages, appears to be happening when writing to the disk. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1013241/+subscriptions
Re: [Qemu-devel] [Bug 1013241] Re: qemu-system-ppc64 hanging occasionally in disk writes
On Tue, 2012-06-19 at 10:16 +, Richard W.M. Jones wrote: > I switched to using virtio-scsi (instead of virtio-blk). This appears to > have solved > this problem, although it brings another problem. I also tried vscsi, which > fixes > both problems. > > Therefore I will (not definitively) claim that the problem lies somewhere in > virtio-blk, > but a workaround seems to be available. What was the virtio-scsi problem ? (Other than SLOF doesn't know about it yet :-) I haven't audited/tested it so it might have endian issues... I have reproduced a similar hang with vscsi in full emulation, I haven't observed your problem with virtio-blk, I plan to spend more time doing some torture testing & debugging this week see if I can find out what's going on. BTW. What was your guest kernel version ? Cheers, Ben.
[Qemu-devel] [Bug 1013241] Re: qemu-system-ppc64 hanging occasionally in disk writes
I switched to using virtio-scsi (instead of virtio-blk). This appears to have solved this problem, although it brings another problem. I also tried vscsi, which fixes both problems. Therefore I will (not definitively) claim that the problem lies somewhere in virtio-blk, but a workaround seems to be available. -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1013241 Title: qemu-system-ppc64 hanging occasionally in disk writes Status in QEMU: New Bug description: I found last week that qemu-system-ppc64 (from git) hangs occasionally under load, and I have a reproducer for it now. Unfortunately the reproducer really takes a long time to run -- usually I can get a hang in under 12 hours. Here is the reproducer case: https://lists.fedoraproject.org/pipermail/ppc/2012-June/001698.html Notes: (1) Verified by one other person (other than me). Happens on both ppc64 and x86-64 host. (2) Happens with both Fedora guest kernel 3.3.4-5.fc17.ppc64 and kernel 3.5.0 that I compiled myself. The test case above contains 3.3.4-5. (3) Seems to be a problem in qemu, not the guest. The reason I think this is because I tried to capture a backtrace of the hang using remote gdb, but gdb just hung when trying to connect to qemu (gdb connects fine before the bug happens). (4) Judging by guest messages, appears to be happening when writing to the disk. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1013241/+subscriptions
