Ubuntu
linux package

using init_on_alloc or init_on_free kernel parameters on ppc64el prevent boot

  1. Groovy (20.10)
  2. Bug #1922593
Bug #1922593 reported by Thadeu Lima de Souza Cascardo
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
Invalid
Undecided
Unassigned
Focal
Confirmed
Low
Thadeu Lima de Souza Cascardo
Groovy
Confirmed
Low
Thadeu Lima de Souza Cascardo

Bug Description

[Impact]
init_on_alloc and init_on_free kernel parameters cannot be used on ppc64el.

[Test case]
Boot the system with and without init_on_alloc and init_on_free kernel parameters, both with 0 and 1 as values.

[Fix]
Upstream commit 04013513cc84c401c7de9023ff3eda7863fc4add ("mm, page_alloc: do not rely on the order of page_poison and init_on_alloc/free parameters") defers setting the static branches to mm_init, which is after jump_label_init has been called, while on ppc64el, parse_early_param is called before that, leading to the crash very early at boot.

[Potential regression]
Boot can be broken, or init_on_alloc/init_on_free may not be properly functioning during early boot or even after that, allowing kernel data leak to happen in the presence of bugs.

Thadeu Lima de Souza Cascardo (cascardo)
Changed in linux (Ubuntu):
status: New → Invalid
Changed in linux (Ubuntu Focal):
status: New → Confirmed
Changed in linux (Ubuntu Groovy):
status: New → Confirmed
assignee: nobody → Thadeu Lima de Souza Cascardo (cascardo)
Changed in linux (Ubuntu Focal):
assignee: nobody → Thadeu Lima de Souza Cascardo (cascardo)
Changed in linux (Ubuntu Groovy):
importance: Undecided → Low
Changed in linux (Ubuntu Focal):
importance: Undecided → Low
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