kernel-packages team mailing list archive

[AlainKnaff <1397649@xxxxxxxxxxxxxxxxxx>]

apport information

** Tags added: apport-collected precise

** Description changed:

  When remounting root read-only in a private mount namespace, then also
  the real root (in default namespace) is read-only.
  
  However, it is then possible to remount the real root read-write, and
  this doesn't (fortunately...) affect the other namespace.
  
  How to reproduce:
  -----------------------------
  (in one console):
  # unshare --mount /bin/bash
  # mount -o remount -r /
  
  (in other console)
  # touch /x
  touch: cannot touch `/x': Read-only file system
  # mount -o remount -w /
  # touch /x
  
  (in first console)
  # touch /x
  touch: cannot touch `/x': Read-only file system
  
  What happened:
  --------------------------
  Read-only mount performed in private mount namespace affected main (default) namespace
  
  What should have happened:
  -----------------------------------------------
  The read-only mount should not have affected the main namespace
  
  (this has been seen in 3.0.0 and also 3.4.0 on precise)
+ --- 
+ ApportVersion: 2.0.1-0ubuntu17.7
+ Architecture: amd64
+ DistroRelease: Ubuntu 12.04
+ MarkForUpload: True
+ NonfreeKernelModules: nvidia
+ Package: linux (not installed)
+ Tags:  precise
+ Uname: Linux 3.4.0-030400-generic x86_64
+ UnreportableReason: The running kernel is not an Ubuntu kernel
+ UpgradeStatus: Upgraded to precise on 2012-10-06 (784 days ago)
+ UserGroups:

** Attachment added: "ProcEnviron.txt"
   https://bugs.launchpad.net/bugs/1397649/+attachment/4271128/+files/ProcEnviron.txt

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https://bugs.launchpad.net/bugs/1397649

Title:
  remounting root read-only in private mount namespace affects main
  namespace

Status in linux package in Ubuntu:
  Incomplete

Bug description:
  When remounting root read-only in a private mount namespace, then also
  the real root (in default namespace) is read-only.

  However, it is then possible to remount the real root read-write, and
  this doesn't (fortunately...) affect the other namespace.

  How to reproduce:
  -----------------------------
  (in one console):
  # unshare --mount /bin/bash
  # mount -o remount -r /

  (in other console)
  # touch /x
  touch: cannot touch `/x': Read-only file system
  # mount -o remount -w /
  # touch /x

  (in first console)
  # touch /x
  touch: cannot touch `/x': Read-only file system

  What happened:
  --------------------------
  Read-only mount performed in private mount namespace affected main (default) namespace

  What should have happened:
  -----------------------------------------------
  The read-only mount should not have affected the main namespace

  (this has been seen in 3.0.0 and also 3.4.0 on precise)
  --- 
  ApportVersion: 2.0.1-0ubuntu17.7
  Architecture: amd64
  DistroRelease: Ubuntu 12.04
  MarkForUpload: True
  NonfreeKernelModules: nvidia
  Package: linux (not installed)
  Tags:  precise
  Uname: Linux 3.4.0-030400-generic x86_64
  UnreportableReason: The running kernel is not an Ubuntu kernel
  UpgradeStatus: Upgraded to precise on 2012-10-06 (784 days ago)
  UserGroups:

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