[Bug 2037567] Re: mantic kernel 6.5.0.1006 Adds io_uring apparmor feature

[John Chittum]

** Description changed:

  starting with kernel package(s) 6.5.0.1006, currently in mantic-
  proposed, `io_uring` is added as a apparmor feature. This change results
  in preseeded snaps being unoptimized, as the mounted apparmor features
  in the chroot do not match the 6.5.0.1006 kernels. On a system running
  with the kernel
  
  cat /sys/kernel/security/apparmor/features/io_uring/mask
  sqpoll override_creds
  
  1. ensure that this is correct with kernel and security teams
  2. ~~ensure that this is the default going forward~~  : Create a 6.5 feature directory as it was pointed out by xnox that Mantic has more than 6.5 kernels at this time.
  
  if 1 and 2, then set the default in `livecd-rootfs` for mounted apparmor
  features to include io_uring
+ 
+ SRU [Jammy]
+ ====
+ 
+ [ Impact ]
+ 
+  * Users of the 6.5 kernel will have un-optimized first boot experiences
+ due to snaps not preseeding with the correct apparmor setup. This
+ directly affects clouds, leading to boot speed degradation of anywhere
+ from 10-30s (depending on snaps installed)
+ 
+ [ Test Plan ]
+ 
+  * Create images with livecd-rootfs:ubuntu/jammy with the SRU'd change (the 6.5 directory in live-build/apparmor)
+    * image must use an "edge" kernel or another forward pointing kernel as the HWE and cloud kernels have not rolled yet.
+  * boot image(s)
+  * check `snap debug seeding`. This should show successful seeding
+    * if a long json output is observed, check the restart-key to see what features are missing. compare to 6.5 in ubuntu/master. check with security, apparmor, and kernel teams
+ 
+ [ Where problems could occur ]
+ 
+  * If there is a difference in rules of 6.5 in mantic and 6.5 being released to Jammy
+  * 
+ 
+ [ Other Info ]
+  
+  * testing may be difficult, as we're trying to catch this before it lands. the codepath selecting kernel version is stable, so adding the configuration area should be safe, even if testing is not easily possible.

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https://bugs.launchpad.net/bugs/2037567

Title:
  mantic kernel 6.5.0.1006 Adds io_uring apparmor feature

Status in livecd-rootfs package in Ubuntu:
  Fix Released

Bug description:
  starting with kernel package(s) 6.5.0.1006, currently in mantic-
  proposed, `io_uring` is added as a apparmor feature. This change
  results in preseeded snaps being unoptimized, as the mounted apparmor
  features in the chroot do not match the 6.5.0.1006 kernels. On a
  system running with the kernel

  cat /sys/kernel/security/apparmor/features/io_uring/mask
  sqpoll override_creds

  1. ensure that this is correct with kernel and security teams
  2. ~~ensure that this is the default going forward~~  : Create a 6.5 feature directory as it was pointed out by xnox that Mantic has more than 6.5 kernels at this time.

  if 1 and 2, then set the default in `livecd-rootfs` for mounted
  apparmor features to include io_uring

  SRU [Jammy]
  ====

  [ Impact ]

   * Users of the 6.5 kernel will have un-optimized first boot
  experiences due to snaps not preseeding with the correct apparmor
  setup. This directly affects clouds, leading to boot speed degradation
  of anywhere from 10-30s (depending on snaps installed)

  [ Test Plan ]

   * Create images with livecd-rootfs:ubuntu/jammy with the SRU'd change (the 6.5 directory in live-build/apparmor)
     * image must use an "edge" kernel or another forward pointing kernel as the HWE and cloud kernels have not rolled yet.
   * boot image(s)
   * check `snap debug seeding`. This should show successful seeding
     * if a long json output is observed, check the restart-key to see what features are missing. compare to 6.5 in ubuntu/master. check with security, apparmor, and kernel teams

  [ Where problems could occur ]

   * If there is a difference in rules of 6.5 in mantic and 6.5 being released to Jammy
   * 

  [ Other Info ]
   
   * testing may be difficult, as we're trying to catch this before it lands. the codepath selecting kernel version is stable, so adding the configuration area should be safe, even if testing is not easily possible.

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