Need a way to disable selected modules with a kernel flag

[Mikko Rantalainen]

Binary package hint: linux-image

Bug #90271 and bug #187671 describe situations where Live CDs and install CDs fail to work because a broken kernel module causes a hang before user has a say. The error may be in an optional kernel module (such as sound card driver or memory card reader) but the end user has no way to prevent kernel from loading a possibly known broken module.

Vanilla kernels from kernel.org support flag disablemodules (e.g. disablemodules=8139too,sdhci prevents linux kernel from loading 8139too.ko or sdhci.ko) but such flag does not seem to work with Ubuntu.

This is a feature request to enable such a flag. It is not needed for normal use but in case of rare hardware exposing a bug in a kernel module not having such a flag prevents one from booting Ubuntu. (I'd prefer booting without network adapter or memory card reader to not booting at all).

This issue also causes slowdowns such as bug #187671 which cannot proceed until bug #90271 is fixed because testing possible fixes for the bug is really hard until the other kernel module has been fixed. (This is because both bugs affect the same laptop hardware and both kernel modules cause a kernel hang.)

I'd consider disablemodules flag similar to acpi flag - it should not be needed but still we need it.

[Mikko Rantalainen (mira)]

Just adding a note that the problem is with Live CD only. With Alternate Install CD one can use sdhci.blacklist=yes kernel flag to allow installing with broken sdhci kernel module.

[Andy Whitcroft (apw)]

I am unable to find any support in the mainline kernel for the "disablemodules" kernel parameter now or in the past? I am also unable to find the option used on the alternate CD.

It seems that a general solution would be possible for non-builtin modules with a simple modification to module-init-tools. A general solution might also be possible at the kernel level to even disable modules which are builtin. Will investigate.

[Charles Evans (crtiger)]

I have a usecase for disabling kernel modules:
I need to disable uas when booting (or at least after booting) a livecd:
All my usb3 to SATA adapters load uas.ko when plugged, then promptly malfunction.
They work when plugged into a usb2 port.
Deleting uas.ko breaks usb hotplug.
I am assuming that usb storage will actually work without uas.

[Charles Evans (crtiger)]

uas.ko hangs, fails, spams dmesg on all 5 HP AMD A10 systems tested, on all AMD USB3 ports if writing to any device that has UAS.

If booting a livecd on a UAS capable device, UAS cannot be unloaded.
UAS will stall any writes to the temp log partition ubuntu creates on the boot device.