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.

Posted: Category: Usability Tagged: Slackware

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