[Kernel-packages] [Bug 1634753] [NEW] srcname from mount rule corrupted under load

[Jamie Strandboge]

Public bug reported:

This came up in snapd spread tests but can be reproduced with:

In an i386 up to date 16.04 VM:

1. in one terminal, run this:

$ cat changehat_reproducer.sh
#!/bin/sh
set -e
sudo sysctl -w kernel.printk_ratelimit=0
sudo snap install hello-world || true

count=0
while /bin/true ; do
    count=$((count+1))
    if [ `echo "$count % 100" | bc` -eq 0 ]; then
        echo "$count runs"
    fi
    hello-world > /dev/null || {
      tail -100 /var/log/syslog | grep DEN && exit
    }
    sudo cat /run/snapd/ns/hello-world.mnt 2>/dev/null || sudo 
/usr/lib/snapd/snap-discard-ns hello-world
done

2. in another terminal run:
$ while do /bin/true ; sudo apparmor_parser -r /etc/apparmor.d/* >/dev/null 
2>&1 ; done

3. In another terminal:
$ tail -f /var/log/syslog|grep DEN


This is not limited to i386.

** Affects: apparmor
     Importance: Critical
     Assignee: John Johansen (jjohansen)
         Status: In Progress

** Affects: linux (Ubuntu)
     Importance: Critical
         Status: Triaged

** Affects: linux (Ubuntu Xenial)
     Importance: Critical
         Status: Triaged

** Affects: linux (Ubuntu Yakkety)
     Importance: Critical
         Status: Triaged


** Tags: aa-kernel

** Also affects: linux (Ubuntu)
   Importance: Undecided
       Status: New

** Also affects: linux (Ubuntu Yakkety)
   Importance: Undecided
       Status: New

** Also affects: linux (Ubuntu Xenial)
   Importance: Undecided
       Status: New

** Changed in: linux (Ubuntu)
       Status: New => Triaged

** Changed in: linux (Ubuntu Xenial)
       Status: New => Triaged

** Changed in: linux (Ubuntu Yakkety)
       Status: New => Triaged

** Changed in: linux (Ubuntu)
   Importance: Undecided => Critical

** Changed in: linux (Ubuntu Xenial)
   Importance: Undecided => Critical

** Changed in: linux (Ubuntu Yakkety)
   Importance: Undecided => Critical

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https://bugs.launchpad.net/bugs/1634753

Title:
  srcname from mount rule corrupted under load

Status in AppArmor:
  In Progress
Status in linux package in Ubuntu:
  Triaged
Status in linux source package in Xenial:
  Triaged
Status in linux source package in Yakkety:
  Triaged

Bug description:
  This came up in snapd spread tests but can be reproduced with:

  In an i386 up to date 16.04 VM:

  1. in one terminal, run this:

  $ cat changehat_reproducer.sh
  #!/bin/sh
  set -e
  sudo sysctl -w kernel.printk_ratelimit=0
  sudo snap install hello-world || true

  count=0
  while /bin/true ; do
      count=$((count+1))
      if [ `echo "$count % 100" | bc` -eq 0 ]; then
          echo "$count runs"
      fi
      hello-world > /dev/null || {
        tail -100 /var/log/syslog | grep DEN && exit
      }
      sudo cat /run/snapd/ns/hello-world.mnt 2>/dev/null || sudo 
/usr/lib/snapd/snap-discard-ns hello-world
  done

  2. in another terminal run:
  $ while do /bin/true ; sudo apparmor_parser -r /etc/apparmor.d/* >/dev/null 
2>&1 ; done

  3. In another terminal:
  $ tail -f /var/log/syslog|grep DEN

  
  This is not limited to i386.

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https://bugs.launchpad.net/apparmor/+bug/1634753/+subscriptions

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