[SRU][Disco][PATCH 0/1] fix for kprobes regression (LP: #1840750)

[Kleber Sacilotto de Souza]

BugLink: https://bugs.launchpad.net/bugs/1840750

[Impact]
ftrace test in ubuntu_kernel_selftests causes a system crash + reboot when
testing "Register/unregister many kprobe events".

[Fix]
The issue has been discussed in the following LKML thread:
https://lkml.org/lkml/2019/6/5/274

and the following 3 upstream commits have been identified to resolve this
issue:

d2a68c4effd8 x86/ftrace: Do not call function graph from dynamic trampolines
3c0dab44e227 x86/ftrace: Set trampoline pages as executable
7298e24f9042 x86/kprobes: Set instruction page as executable

>From these commits, the Disco kernel currently in -proposed (5.0.0-26.27) is
missing only the following commit, which has been already committed as part of
LP: #1839887 (Disco update: upstream stable patchset 2019-08-12) but not yet
released:

7298e24f9042 x86/kprobes: Set instruction page as executable

[Regression potential]
The commit touches the x86/kprobes code so there's a chance of regression there
which I would flag as medium. However, it has been applied upstream for
v5.2-rc1 and there is no follow-up commits marked as fix for it.

Nadav Amit (1):
  x86/kprobes: Set instruction page as executable

 arch/x86/kernel/kprobes/core.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

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2.17.1