Public bug reported:

== SRU Justification Eoan ==

Now that 5.4 contains a fix to the bootup regression due to the lack of
entropy at bootable we should apply this fix and also revert the revert
of commit "Revert "ext4: make __ext4_get_inode_loc plug"".

== Fix ==

So, to clarify, apply the two upstream 5.4-rc commits:

commit 50ee7529ec4500c88f8664560770a7a1b65db72b
Author: Linus Torvalds <torva...@linux-foundation.org>
Date:   Sat Sep 28 16:53:52 2019 -0700

    random: try to actively add entropy rather than passively wait for
it

commit 02f03c4206c1b2a7451d3b3546f86c9c783eac13
Author: Linus Torvalds <torva...@linux-foundation.org>
Date:   Sun Sep 29 17:59:23 2019 -0700

    Revert "Revert "ext4: make __ext4_get_inode_loc plug""

I've benchmarked the Eoan kernel with these two patches and found the
following speed improvements:

git grep of the kernel: 0.14%
building fwts: 0.40%
build stress-ng 0.45%
tar up kernel source: 7.6%
boot time of eoan cloud image: 10.5%

So I think the speed improvements justify the SRU.

== Regression potential ==

minor change to ext4, which has been regression tested, so risk here is
small.  The entropy change will alter the random number generation, but
I believe this does not change the cryptographical security of the
random numbers being generated, so think this change is not security
risk.

originally the ext4 change caused boot time user space regressions
because of the entropy change of this fix, but the random fix addresses
this, so I believe this risk is now zero.

** Affects: linux (Ubuntu)
     Importance: High
     Assignee: Colin Ian King (colin-king)
         Status: In Progress

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

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

** Changed in: linux (Ubuntu)
     Assignee: (unassigned) => Colin Ian King (colin-king)

** Description changed:

- == SRU Justifucation Eoan ==
+ == SRU Justification Eoan ==
  
  Now that 5.4 contains a fix to the bootup regression due to the lack of
  entropy at bootable we should apply this fix and also revert the revert
  of commit "Revert "ext4: make __ext4_get_inode_loc plug"".
  
  == Fix ==
  
  So, to clarify, apply the two upstream 5.4-rc commits:
  
  commit 50ee7529ec4500c88f8664560770a7a1b65db72b
  Author: Linus Torvalds <torva...@linux-foundation.org>
  Date:   Sat Sep 28 16:53:52 2019 -0700
  
-     random: try to actively add entropy rather than passively wait for
+     random: try to actively add entropy rather than passively wait for
  it
  
  commit 02f03c4206c1b2a7451d3b3546f86c9c783eac13
  Author: Linus Torvalds <torva...@linux-foundation.org>
  Date:   Sun Sep 29 17:59:23 2019 -0700
  
-     Revert "Revert "ext4: make __ext4_get_inode_loc plug""
+     Revert "Revert "ext4: make __ext4_get_inode_loc plug""
  
- 
- I've benchmarked the Eoan kernel with these two patches and found the 
following speed improvements:
+ I've benchmarked the Eoan kernel with these two patches and found the
+ following speed improvements:
  
  git grep of the kernel: 0.14%
  building fwts: 0.40%
  build stress-ng 0.45%
  tar up kernel source: 7.6%
  boot time of eoan cloud image: 10.5%
  
  So I think this justifies the speed improvements.
  
  == Regression potential ==
  
  minor change to ext4, which has been regression tested, so risk here is
  small.  The entropy change will alter the random number generation, but
  I believe this does not change the cryptographical security of the
  random numbers being generated, so think this change is not security
  risk.
  
  originally the ext4 change caused boot time user space regressions
  because of the entropy change of this fix, but the random fix addresses
  this, so I believe this risk is now zero.

** Description changed:

  == SRU Justification Eoan ==
  
  Now that 5.4 contains a fix to the bootup regression due to the lack of
  entropy at bootable we should apply this fix and also revert the revert
  of commit "Revert "ext4: make __ext4_get_inode_loc plug"".
  
  == Fix ==
  
  So, to clarify, apply the two upstream 5.4-rc commits:
  
  commit 50ee7529ec4500c88f8664560770a7a1b65db72b
  Author: Linus Torvalds <torva...@linux-foundation.org>
  Date:   Sat Sep 28 16:53:52 2019 -0700
  
      random: try to actively add entropy rather than passively wait for
  it
  
  commit 02f03c4206c1b2a7451d3b3546f86c9c783eac13
  Author: Linus Torvalds <torva...@linux-foundation.org>
  Date:   Sun Sep 29 17:59:23 2019 -0700
  
      Revert "Revert "ext4: make __ext4_get_inode_loc plug""
  
  I've benchmarked the Eoan kernel with these two patches and found the
  following speed improvements:
  
  git grep of the kernel: 0.14%
  building fwts: 0.40%
  build stress-ng 0.45%
  tar up kernel source: 7.6%
  boot time of eoan cloud image: 10.5%
  
- So I think this justifies the speed improvements.
+ So I think the speed improvements justify the SRU.
  
  == Regression potential ==
  
  minor change to ext4, which has been regression tested, so risk here is
  small.  The entropy change will alter the random number generation, but
  I believe this does not change the cryptographical security of the
  random numbers being generated, so think this change is not security
  risk.
  
  originally the ext4 change caused boot time user space regressions
  because of the entropy change of this fix, but the random fix addresses
  this, so I believe this risk is now zero.

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https://bugs.launchpad.net/bugs/1846486

Title:
  revert the revert of ext4: make __ext4_get_inode_loc plug

Status in linux package in Ubuntu:
  In Progress

Bug description:
  == SRU Justification Eoan ==

  Now that 5.4 contains a fix to the bootup regression due to the lack
  of entropy at bootable we should apply this fix and also revert the
  revert of commit "Revert "ext4: make __ext4_get_inode_loc plug"".

  == Fix ==

  So, to clarify, apply the two upstream 5.4-rc commits:

  commit 50ee7529ec4500c88f8664560770a7a1b65db72b
  Author: Linus Torvalds <torva...@linux-foundation.org>
  Date:   Sat Sep 28 16:53:52 2019 -0700

      random: try to actively add entropy rather than passively wait for
  it

  commit 02f03c4206c1b2a7451d3b3546f86c9c783eac13
  Author: Linus Torvalds <torva...@linux-foundation.org>
  Date:   Sun Sep 29 17:59:23 2019 -0700

      Revert "Revert "ext4: make __ext4_get_inode_loc plug""

  I've benchmarked the Eoan kernel with these two patches and found the
  following speed improvements:

  git grep of the kernel: 0.14%
  building fwts: 0.40%
  build stress-ng 0.45%
  tar up kernel source: 7.6%
  boot time of eoan cloud image: 10.5%

  So I think the speed improvements justify the SRU.

  == Regression potential ==

  minor change to ext4, which has been regression tested, so risk here
  is small.  The entropy change will alter the random number generation,
  but I believe this does not change the cryptographical security of the
  random numbers being generated, so think this change is not security
  risk.

  originally the ext4 change caused boot time user space regressions
  because of the entropy change of this fix, but the random fix
  addresses this, so I believe this risk is now zero.

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