[Bug 1602717] Re: hw-detect modprobes blindly, ignoring blacklists

[bugproxy]

------- Comment From mauricfo at br.ibm.com 2016-09-29 19:31 EDT-------
This has been verified successfully w/ the nvme driver.
Updating tags.

On the partitioner dialog, exited to shell and verified (below).

1) Enabling -proposed & blacklist options, the nvme module is not loaded
and nvme devices are not present:

~ # cat /proc/cmdline
method=http://ports.ubuntu.com/ubuntu-ports/dists/xenial-updates/main/installer-ppc64el/ apt-setup/proposed=true modprobe.blacklist=nvme

~ # lsmod | grep nvme
~ #

~ # ls -1 /dev/nvme*
ls: /dev/nvme*: No such file or directory

2) Enabling -proposed but not the blacklist option, the nvme module is
loaded and nvme devices are present:

~ # cat /proc/cmdline
method=http://ports.ubuntu.com/ubuntu-ports/dists/xenial-updates/main/installer-ppc64el/ apt-setup/proposed=true

~ # lsmod | grep nvme
nvme                   82444  0

~ # ls -1 /dev/nvme*
/dev/nvme0
/dev/nvme0n1
/dev/nvme0n1p1

** Tags removed: verification-needed
** Tags added: verification-done

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https://bugs.launchpad.net/bugs/1602717

Title:
  hw-detect modprobes blindly, ignoring blacklists

Status in hw-detect package in Ubuntu:
  In Progress
Status in hw-detect source package in Xenial:
  Fix Committed

Bug description:
  [Impact]
  Any system requiring specific modules to be blacklisted at install-time, when using server or alternate images.

  [Test cases]
  Boot the installer w/ this boot/kernel cmdline option (the alias w/ dashes is not required, but is here just in case):
      modprobe.blacklist=scsi_dh_alua,scsi-dh-alua

  On the dialog for username/password, select Go Back, then Exit to
  shell:

  The blacklist is detected/present in the config:

  ~ # modprobe -c | grep alua
  blacklist scsi_dh_alua
  blacklist scsi-dh-alua

  But the module is insmod-ed anyway:

  ~ # modprobe -v -n scsi-dh-alua
  insmod /lib/modules/4.4.0-21-generic/kernel/drivers/scsi/device_handler/scsi_dh_alua.ko

  Unless -b is used:

  ~ # modprobe -v -n -b scsi-dh-alua
  ~ #

  [Regression Potential]
  Failure to load kernel modules at boot time due to unexpectedly blacklisted modules would consistute a regression for this bug report.

  
  == Comment: #0 - Mauricio Faria De Oliveira - 2016-07-11 18:47:59 ==
  ---Problem Description---
  modprobe does not honor blacklist options in kernel cmdline unless -b is used (at least on the installer)

  The modprobe.blacklist option is required as a work-around until a
  solution to a device-driver bug is found (IBM LTC bug 138273).

  I've gone through the code of the kmod src pkg, but didn't spot anything obvious.
  Passing along to the Ubuntu team.

  Contact Information = Mauricio Faria de Oliveira <mauricfo at br.ibm.com>
  / Lekshmi C. Pillai <lekshmi.cpillai at in.ibm.com>

  ---Steps to Reproduce---
   Boot the installer w/ this boot/kernel cmdline option (the alias w/ dashes is not required, but is here just in case):
      modprobe.blacklist=scsi_dh_alua,scsi-dh-alua

  On the dialog for username/password, select Go Back, then Exit to
  shell:

  The blacklist is detected/present in the config:

  ~ # modprobe -c | grep alua
  blacklist scsi_dh_alua
  blacklist scsi-dh-alua

  But the module is insmod-ed anyway:

  ~ # modprobe -v -n scsi-dh-alua
  insmod /lib/modules/4.4.0-21-generic/kernel/drivers/scsi/device_handler/scsi_dh_alua.ko

  Unless -b is used:

  ~ # modprobe -v -n -b scsi-dh-alua
  ~ #

  Installer kernel:
  [    0.000000] Linux version 4.4.0-21-generic (buildd at bos01-ppc64el-017) (gcc version 5.3.1 20160413 (Ubuntu/IBM 5.3.1-14ubuntu2) ) #37-Ubuntu SMP Mon Apr 18 18:30:22 UTC 2016 (Ubuntu 4.4.0-21.37-generic 4.4.6)

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