Flashes (Alerts)
Abstract
The ppc64 cpu --smt=1 command can result in hardlockups, rendering the system unusable until it is rebooted. This hardlockups issue occurs on a large configuration system with at least 4 TB of memory and 240 processing cores.
Content
Linux Releases Affected
SUSE Linux Enterprise Server 15, Service Pack 4
IBM Systems Affected
9080-HEX (IBM Power E1080).
Symptoms
When you run the ppc64_cpu command on large configuration systems, it can cause hardlockups, and the system might hang.
Workaround
Before using the ppc64_cpu --smt command, you can carry out one of the following actions to prevent hardlockups:
Procedure 1: Use the following code to boot the kernel with boot parameter:
nmi_watchdog=0
Procedure 2: After the boot, you can disable soft watchdog and nmi watchdog detectors by using the
following code:
echo 0 > /proc/sys/kernel/soft_watchdog
echo 0 > /proc/sys/kernel/nmi_watchdog
or
sysctl -w kernel.nmi_watchdog=0
sysctl -w kernel.soft_watchdog=0
Once you run the ppc64_cpu --smt command, you can enable the soft watchdog and nmi watchdog
detectors by using the following code:
echo 1 > /proc/sys/kernel/soft_watchdog
echo 1 > /proc/sys/kernel/nmi_watchdog
or
sysctl -w kernel.nmi_watchdog=1
sysctl -w kernel.soft_watchdog=1
Fix Outlook
None.
I/O device impacted
None.
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Document Information
Modified date:
13 December 2022
UID
ibm16842095