BUG: unable to handle page fault for address
After updating the office desktop to Slackware 15.0, several times after running a backup shell script the system would crash. The system log showed the following:
BUG: unable to handle page fault for address: ffffffffc04eadff #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page Oops: 0000 [#1] PREEMPT SMP NOPTI
Searching the web did not help.
The crash is not a hard freeze. The kernel magic keys could be used to reboot the system. Although not always repeatable, the cause seemed to be related to removing the
xhci_hcd kernel module when powering down.
Digging deeper revealed there now is a third related
xhci_pci_renesas module being loaded. Updating the
rc.local_shutdown script to remove that module before removing the
xhci_hcd module seemed to help.
This approach has stopped the behavior. Whether removing these modules is necessary with a 5.x kernel is unknown and testing is planned for another day.
Newer is not always better.
Yet Another Example why updating computers is so frustrating.
Something always breaks. Always.