------- Comment From seb...@de.ibm.com 2018-09-05 05:06 EDT------- (In reply to comment #8) > @IBM: Even if we do not have NVMe devices in our Z machine (hence we cannot > test this on s390x by ourselves) it would be good and helpful if you can > share a description / or some steps of a potential test case. > This would help judging the regression risk in case of an SRU to 18.04 (and > is needed for a SRU anyway).
The trigger is a PCI function whose driver requests more interrupts than the architectural maximum. Currently this is only possible with a machine that supports 64 CPUs (or more) with a NVMe function attached. Note that the LPAR does not have to use >=64 CPUs since the NVMe driver uses num_possible_cpus() which is resolved to the machine maximum on s390 (since all CPUs are hot-pluggable). The oops happens after the driver calls pci_alloc_irq_vectors during device probing - so most likely the system will panic during boot. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1790480 Title: random oopses on s390 systems using NVMe devices Status in Ubuntu on IBM z Systems: Triaged Status in linux package in Ubuntu: Fix Committed Status in linux source package in Bionic: New Bug description: Random oopses on s390 systems using NVMe and running the Ubuntu 18.04.1 kernel have been reported. Bisect of the upstream kernel points to: 16ccfff28976 nvme: pci: pass max vectors as num_possible_cpus() to pci_alloc_irq_vectors This commit is correct but reveals a bug in s390s IRQ setup routine. A fix is available fixed via: Commit-ID : 866f3576a72b2233a76dffb80290f8086dc49e17 Need also be applied for Ubuntu 18.10 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1790480/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
