<s>
Ksplice	B-Application
is	O
an	O
open-source	O
extension	O
of	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
that	O
allows	O
security	O
patches	O
to	O
be	O
applied	O
to	O
a	O
running	O
kernel	B-Operating_System
without	O
the	O
need	O
for	O
reboots	O
,	O
avoiding	O
downtimes	O
and	O
improving	O
availability	O
(	O
a	O
technique	O
broadly	O
referred	O
to	O
as	O
dynamic	B-Architecture
software	I-Architecture
updating	I-Architecture
)	O
.	O
</s>
<s>
Ksplice	B-Application
supports	O
only	O
the	O
patches	O
that	O
do	O
not	O
make	O
significant	O
semantic	O
changes	O
to	O
kernel	B-Operating_System
's	O
data	B-General_Concept
structures	I-General_Concept
.	O
</s>
<s>
Ksplice	B-Application
has	O
been	O
implemented	O
for	O
Linux	B-Operating_System
on	O
the	O
x86-64	B-Device
and	O
AArch64	B-Architecture
architectures	O
.	O
</s>
<s>
It	O
was	O
developed	O
by	O
Ksplice	B-Application
,	O
Inc	O
.	O
until	O
21	O
July	O
2011	O
,	O
when	O
Oracle	B-Application
acquired	O
Ksplice	B-Application
and	O
then	O
offered	O
support	O
for	O
Oracle	B-Application
Linux	B-Operating_System
.	O
</s>
<s>
Support	O
for	O
Red	O
Hat	O
Enterprise	O
Linux	B-Operating_System
was	O
dropped	O
and	O
turned	O
into	O
a	O
free	O
30-day	O
trial	O
for	O
RHEL	O
customers	O
as	O
an	O
incentive	O
to	O
migrate	O
to	O
Oracle	B-Application
Linux	B-Operating_System
Premier	O
Support	O
.	O
</s>
<s>
Ksplice	B-Application
is	O
today	O
offered	O
on	O
the	O
two	O
kernel	B-Operating_System
flavors	O
distributed	O
with	O
Oracle	B-Application
Linux	B-Operating_System
:	O
</s>
<s>
,	O
Ksplice	B-Application
is	O
available	O
for	O
free	O
on	O
desktop	O
Linux	B-Operating_System
installations	O
,	O
with	O
official	O
support	O
available	O
for	O
Ubuntu	B-Operating_System
Linux	I-Operating_System
distribution	I-Operating_System
.	O
</s>
<s>
Ksplice	B-Application
takes	O
as	O
input	O
a	O
unified	O
diff	O
and	O
the	O
original	O
kernel	B-Operating_System
source	O
code	O
,	O
and	O
it	O
updates	O
the	O
running	O
kernel	B-Operating_System
in	O
memory	B-General_Concept
.	O
</s>
<s>
Using	O
Ksplice	B-Application
does	O
not	O
require	O
any	O
preparation	O
before	O
the	O
system	O
is	O
originally	O
booted	B-Operating_System
,	O
(	O
the	O
running	O
kernel	B-Operating_System
needs	O
no	O
special	O
prior	O
compiling	B-Language
,	O
for	O
example	O
)	O
.	O
</s>
<s>
In	O
order	O
to	O
generate	O
an	O
update	O
,	O
Ksplice	B-Application
must	O
determine	O
what	O
code	O
within	O
the	O
kernel	B-Operating_System
has	O
been	O
changed	O
by	O
the	O
source	O
code	O
patch	O
.	O
</s>
<s>
Ksplice	B-Application
performs	O
this	O
analysis	O
at	O
the	O
Executable	O
and	O
Linkable	O
Format	O
(	O
ELF	O
)	O
object	O
code	O
layer	O
,	O
rather	O
than	O
at	O
the	O
C	B-Language
source	O
code	O
layer	O
.	O
</s>
<s>
To	O
apply	O
a	O
patch	O
,	O
Ksplice	B-Application
first	O
freezes	O
execution	O
of	O
a	O
computer	O
so	O
it	O
is	O
the	O
only	O
program	O
running	O
.	O
</s>
<s>
The	O
system	O
verifies	O
that	O
no	O
processors	B-General_Concept
were	O
in	O
the	O
middle	O
of	O
executing	O
functions	O
that	O
will	O
be	O
modified	O
by	O
the	O
patch	O
.	O
</s>
<s>
Ksplice	B-Application
modifies	O
the	O
beginning	O
of	O
changed	O
functions	O
so	O
that	O
they	O
instead	O
point	O
to	O
new	O
,	O
updated	O
versions	O
of	O
those	O
functions	O
,	O
and	O
modifies	O
data	O
and	O
structures	O
in	O
memory	B-General_Concept
that	O
need	O
to	O
be	O
changed	O
.	O
</s>
<s>
Finally	O
,	O
Ksplice	B-Application
resumes	O
each	O
processor	O
running	O
where	O
it	O
left	O
off	O
.	O
</s>
<s>
To	O
be	O
fully	O
automatic	O
,	O
Ksplice	B-Application
's	O
design	O
was	O
originally	O
limited	O
to	O
patches	O
that	O
did	O
not	O
introduce	O
semantic	O
changes	O
to	O
data	B-General_Concept
structures	I-General_Concept
,	O
since	O
most	O
Linux	B-Operating_System
kernel	I-Operating_System
security	O
patches	O
do	O
not	O
make	O
these	O
kinds	O
of	O
changes	O
.	O
</s>
<s>
An	O
evaluation	O
against	O
Linux	B-Operating_System
kernel	I-Operating_System
security	O
patches	O
from	O
May	O
2005	O
to	O
May	O
2008	O
found	O
that	O
Ksplice	B-Application
was	O
able	O
to	O
apply	O
fixes	O
for	O
all	O
the	O
64	O
significant	O
kernel	B-Operating_System
vulnerabilities	O
discovered	O
in	O
that	O
interval	O
.	O
</s>
<s>
In	O
2009	O
,	O
major	O
Linux	B-Operating_System
vendors	O
asked	O
their	O
customers	O
to	O
install	O
a	O
kernel	B-Operating_System
update	O
more	O
than	O
once	O
per	O
month	O
.	O
</s>
<s>
For	O
patches	O
that	O
do	O
introduce	O
semantic	O
changes	O
to	O
data	B-General_Concept
structures	I-General_Concept
,	O
Ksplice	B-Application
requires	O
a	O
programmer	O
to	O
write	O
a	O
short	O
amount	O
of	O
additional	O
code	O
to	O
help	O
apply	O
the	O
patch	O
.	O
</s>
<s>
The	O
Ksplice	B-Application
software	O
was	O
created	O
by	O
four	O
MIT	O
students	O
based	O
on	O
Jeff	O
Arnold	O
's	O
master	O
's	O
thesis	O
,	O
and	O
they	O
later	O
created	O
Ksplice	B-Application
,	O
Inc	O
.	O
Around	O
May	O
2009	O
,	O
the	O
company	O
won	O
the	O
MIT	O
$100K	O
Entrepreneurship	O
Competition	O
and	O
the	O
Cyber	O
Security	O
Challenge	O
of	O
Global	O
Security	O
Challenge	O
.	O
</s>
<s>
Whereas	O
the	O
Ksplice	B-Application
software	O
was	O
provided	O
under	O
an	O
open	O
source	O
license	O
,	O
Ksplice	B-Application
,	O
Inc	O
.	O
provided	O
a	O
service	O
to	O
make	O
it	O
easier	O
to	O
use	O
the	O
software	O
.	O
</s>
<s>
Ksplice	B-Application
,	O
Inc	O
.	O
provided	O
prebuilt	O
and	O
tested	O
updates	O
for	O
the	O
Red	O
Hat	O
,	O
CentOS	O
,	O
Debian	O
,	O
Ubuntu	B-Operating_System
and	O
Fedora	O
Linux	B-Application
distributions	I-Application
.	O
</s>
<s>
The	O
virtualization	O
technologies	O
OpenVZ	B-Language
and	O
Virtuozzo	O
were	O
also	O
supported	O
.	O
</s>
<s>
Updates	O
for	O
Ubuntu	B-Operating_System
Desktop	O
and	O
Fedora	O
systems	O
were	O
provided	O
free	O
of	O
charge	O
,	O
whereas	O
other	O
platforms	O
were	O
offered	O
on	O
a	O
subscription	O
basis	O
.	O
</s>
<s>
On	O
21	O
July	O
2011	O
,	O
Oracle	B-Application
Corporation	I-Application
announced	O
that	O
they	O
acquired	O
Ksplice	B-Application
,	O
Inc	O
.	O
At	O
the	O
time	O
the	O
company	O
was	O
acquired	O
,	O
Ksplice	B-Application
,	O
Inc	O
.	O
claimed	O
to	O
have	O
over	O
700	O
companies	O
using	O
the	O
service	O
to	O
protect	O
over	O
100,000	O
servers	O
.	O
</s>
<s>
While	O
the	O
service	O
had	O
been	O
available	O
for	O
multiple	O
Linux	B-Application
distributions	I-Application
,	O
it	O
was	O
stated	O
at	O
the	O
time	O
of	O
acquisition	O
that	O
"	O
Oracle	B-Application
believes	O
it	O
will	O
be	O
the	O
only	O
enterprise	O
Linux	B-Operating_System
provider	O
that	O
can	O
offer	O
zero	O
downtime	O
updates.	O
"	O
</s>
<s>
More	O
explicitly	O
,	O
"	O
Oracle	B-Application
does	O
not	O
plan	O
to	O
support	O
the	O
use	O
of	O
Ksplice	B-Application
technology	O
with	O
Red	O
Hat	O
Enterprise	O
Linux.	O
"	O
</s>
<s>
Existing	O
legacy	O
customers	O
continue	O
to	O
be	O
supported	O
by	O
Ksplice	B-Application
,	O
but	O
no	O
new	O
customers	O
are	O
being	O
accepted	O
for	O
other	O
platforms	O
.	O
</s>
<s>
,	O
Ksplice	B-Application
is	O
available	O
for	O
free	O
on	O
Ubuntu	B-Operating_System
.	O
</s>
<s>
In	O
January	O
2016	O
,	O
Ksplice	B-Application
was	O
integrated	O
into	O
Oracle	B-Application
's	O
Unbreakable	O
Enterprise	O
Kernel	B-Operating_System
Release4	O
for	O
Oracle	B-Application
Linux6	O
and	O
7	O
,	O
which	O
is	O
Oracle	B-Application
's	O
redistribution	O
of	O
Red	O
Hat	O
Enterprise	O
Linux	B-Operating_System
.	O
</s>
<s>
As	O
of	O
March	O
2023	O
,	O
Ksplice	B-Application
is	O
integrated	O
into	O
:	O
</s>
