Hipersocket interface runs into netdev watchdog timeout and ksoftirqd spins at 100% CPU

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Environment

SUSE Linux Enterprise Server 10 Service Pack 4

Situation

Applies to IBM System z:
After updating the Linux kernel to version 2.6.16.60-0.95.1, NETDEV WATCHDOG transmit timeout kernel messages appear for Hipersocket interfaces under z/VM and the ksoftirqd kernel thread spins at 100% CPU.

Resolution

The newly release kernel package 2.6.16.60-0.97.1 contains a correction for this issue.

Cause

The Linux kernel package 2.6.16.60-0.95.1 introduced a regression that can lead to a wrong count of QDIO error buffers for devices with QIOASSIST ON under z/VM.

Disclaimer

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