Disable unnecessary floppy kernel module #449
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neddp
approved these changes
Oct 28, 2025
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I don’t know if this is still true but the vsphere cpi used this module for its equivalent of cloud init. It may have moved to virtual CDs but we need to double check this. |
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Pretty sure the vsphere cpi uses a virtual cd drive, at least according to https://bosh.io/docs/vsphere/#concepts |
rkoster
approved these changes
Oct 30, 2025
s4heid
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Nov 6, 2025
In a previous change (cloudfoundry#449), loading the floppy module was disabled by redirecting the floppy command to true, which effectively prevents manual loading of the module using `modprobe floppy`. However, Buffer I/O errors observed in the `dmesg` output indicate that the kernel is still attempting to load the floppy module when the floppy hardware is presented. ```txt blk_update_request: I/O error, dev fd0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 floppy0: disk absent or changed during operation ``` This suggests that that during boot: 1. Kernel detects floppy controller hardware 2. udev/kernel auto-loads floppy module (install directive not active yet) 3. Floppy driver starts, finds no disk → I/O errors 4. install directive becomes active (too late!) When using both directives below, these errors can be avoided: - `install floppy /bin/true`: This redirects any attempt to load the floppy module to true (which does nothing) - `blacklist floppy`: This explicitly prevents the kernel from automatically loading the floppy module
s4heid
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Nov 8, 2025
In a previous change (cloudfoundry#449), loading the floppy module was disabled by redirecting the floppy command to true, which effectively prevents manual loading of the module using `modprobe floppy`. However, Buffer I/O errors observed in the `dmesg` output indicate that the kernel is still attempting to load the floppy module when the floppy hardware is presented. ```txt blk_update_request: I/O error, dev fd0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 floppy0: disk absent or changed during operation ``` This suggests that during boot: 1. Kernel detects floppy controller hardware 2. udev/kernel auto-loads floppy module (install directive not active yet) 3. Floppy driver starts, finds no disk → I/O errors 4. install directive becomes active (too late!) update-initramfs must be executed because the initramfs is built at image creation time and contains kernel modules and configuration used before the root filesystem mounts. The blacklist in /etc/modprobe.d only affects modprobe after the root filesystem is active. If the initramfs contains a floppy.k and is not rebuilt after the blacklist has been applied, the initramfs auto-loads the floppy driver.
s4heid
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Nov 9, 2025
In a previous change (cloudfoundry#449), loading the floppy module was disabled by redirecting the floppy command to true, which effectively prevents manual loading of the module using `modprobe floppy`. However, Buffer I/O errors observed in the `dmesg` output indicate that the kernel is still attempting to load the floppy module when the floppy hardware is presented. ```txt blk_update_request: I/O error, dev fd0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 floppy0: disk absent or changed during operation ``` This suggests that during boot: 1. Kernel detects floppy controller hardware 2. udev/kernel auto-loads floppy module (install directive not active yet) 3. Floppy driver starts, finds no disk → I/O errors 4. install directive becomes active (too late!) The blacklist in /etc/modprobe.d only affects modprobe after the root filesystem is active. If the initramfs contains a `floppy.ko` file and is not rebuilt after the blacklist has been applied, the initramfs auto-loads the floppy driver. `update-initramfs` rebuilds the initramfs and includes the /etc/modprobe.d rules to the root fs.
s4heid
added a commit
to s4heid/bosh-linux-stemcell-builder
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Nov 10, 2025
In a previous change (cloudfoundry#449), loading the floppy module was disabled by redirecting the floppy command to true. However, Buffer I/O errors observed in the `dmesg` output indicate that the kernel is still attempting to load the floppy module when the hardware supports it. ```txt blk_update_request: I/O error, dev fd0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 floppy0: disk absent or changed during operation ``` This suggests that during boot: 1. Kernel detects floppy controller hardware 2. udev/kernel auto-loads floppy module (install directive not active yet) 3. Floppy driver starts, finds no disk → I/O errors 4. install directive becomes active (too late!) The blacklist in /etc/modprobe.d only affects modprobe after the root filesystem is active. If the initramfs contains a `floppy.ko` file and is not rebuilt after the blacklist has been applied, the initramfs auto-loads the floppy driver. `update-initramfs` rebuilds the initramfs and includes the /etc/modprobe.d rules to the root fs.
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This PR removes loading of the legacy floppy module from the stemcell build.
Rationale: