4.14. kexec-tools

Executing kdump on an IBM Bladecenter QS21 or QS22 configured with NFS root will fail. To avoid this, specify an NFS dump target in /etc/kdump.conf. (BZ#368981)

Some forcedeth based devices may encounter difficulty accessing memory above 4GB during operation in a kdump kernel. To work around this issue, add the following line to the /etc/sysconfig/kdump file:

KDUMP_COMMANDLINE_APPEND="dma_64bit=0"

This work around prevents the forcedeth network driver from using high memory resources in the kdump kernel, allowing the network to function properly.

The system may not successfully reboot into a kexec/kdump kernel if X is running and using a driver other than vesa. This problem only exists with ATI Rage XL graphics chipsets.

If X is running on a system equipped with ATI Rage XL, ensure that it is using the vesa driver in order to successfully reboot into a kexec/kdump kernel. (BZ#221656)

kdump now serializes drive creation registration with the rest of the kdump process. Consequently, kdump may hang waiting for IDE drives to be initialized. In these cases, it is recommended that IDE disks not be used with kdump. (BZ#473852)

It is possible in rare circumstances, for makedumpfile to produce erroneous results but not have them reported. This is due to the fact that makedumpfile processes its output data through a pipeline consisting of several stages. If makedumpfile fails, the other stages will still succeed, effectively masking the failure. Should a vmcore appear corrupt, and makedumpfile is in use, it is recommended that the core be recorded without makedumpfile and a bug be reported. (BZ#475487)

kdump now restarts when CPUs or DIMMs are hot-added to a system. If multiple items are added at the same time, several sequential restarts may be encountered. This behavior is intentional, as it minimizes the time-frame where a crash may occur while memory or processors are not being tracked by kdump. (BZ#474409)

Some Itanium systems cannot properly produce console output from the kexec purgatory code. This code contains instructions for backing up the first 640k of memory after a crash.

While purgatory console output can be useful in diagnosing problems, it is not needed for kdump to properly function. As such, if your Itanium system resets during a kdump operation, disable console output in purgatory by adding --noio to the KEXEC_ARGS variable in /etc/sysconfig/kdump. (BZ#436426)