[Bug 1931886] Re: show-regs can cause some samsung controllers to go offline

[Bug Watch Updater]

** Changed in: nvme-cli (Debian)
       Status: Confirmed => Fix Released

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Title:
  show-regs can cause some samsung controllers to go offline

Status in nvme-cli package in Ubuntu:
  In Progress
Status in nvme-cli source package in Groovy:
  New
Status in nvme-cli source package in Hirsute:
  New
Status in nvme-cli source package in Impish:
  In Progress
Status in nvme-cli package in Debian:
  Fix Released

Bug description:
  [Impact]
  nvme show-regs has been found to cause certain Samsung controllers
  (MZ1L21T9HCLS in particular) to go offline.

  [Test Case]
  Run `nvme show-regs` on an effected controller device. Messages similar to this will appear in dmesg:
  [963314.311332] nvme nvme2: controller is down; will reset: CSTS=0x3, PCI_STATUS=0x10
  [963334.951328] nvme nvme2: Device not ready; aborting reset
  [963334.963114] nvme nvme2: Removing after probe failure status: -19
  [963334.999600] blk_update_request: I/O error, dev nvme2n1, sector 1050640 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
  [963335.023410] md: super_written gets error=10
  [963335.033842] md/raid1:md0: Disk failure on nvme2n1p2, disabling device.
                  md/raid1:md0: Operation continuing on 1 devices.
  [  +0.009599] XFS (md127): log I/O error -5
  [  +0.015136] XFS (md127): xfs_do_force_shutdown(0x2) called from line 1250 of file fs/xfs/xfs_log.c. Return address = 00000000d0ea8129
  [  +0.000001] XFS (md127): Log I/O Error Detected. Shutting down filesystem
  [  +0.009290] XFS (md127): Please unmount the filesystem and rectify the problem(s)

  [Fix]
  This has been fixed upstream with the following commits:
    https://github.com/linux-nvme/nvme-cli/commit/33e60ff64a043b189d2661543b417b21b6f3667b
    https://github.com/linux-nvme/nvme-cli/commit/d43d545a68cc6cea5ac78fda4edeedf3b5198847

  [What Could Go Wrong]
  Because the register prmsc is now split into prmscl/prmscu as the specification requires, the displayed registers will be different in showregs output. This might surprise any code that is trying to parse this output. Also upstream made a formatting change here that adds additional whitespace to a field when running w/ -H (human-readable mode):

  This:
  Controller Base Address (CBA)		: 0
  Became:
  Controller Base Address         (CBA): 0

  It is human-readable mode which at least I interpret as "not for
  scripting", but it's possible that there is a user expecting that
  specific format. We could carry an additional patch to restore this
  whitespace if the SRU team is so inclined.

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