CVE-2021-46990

In the Linux kernel, the following vulnerability has been resolved:

powerpc/64s: Fix crashes when toggling entry flush barrier

The entry flush mitigation can be enabled/disabled at runtime via a
debugfs file (entry_flush), which causes the kernel to patch itself to
enable/disable the relevant mitigations.

However depending on which mitigation we're using, it may not be safe to
do that patching while other CPUs are active. For example the following
crash:

  sleeper[15639]: segfault (11) at c000000000004c20 nip c000000000004c20 lr c000000000004c20

Shows that we returned to userspace with a corrupted LR that points into
the kernel, due to executing the partially patched call to the fallback
entry flush (ie. we missed the LR restore).

Fix it by doing the patching under stop machine. The CPUs that aren't
doing the patching will be spinning in the core of the stop machine
logic. That is currently sufficient for our purposes, because none of
the patching we do is to that code or anywhere in the vicinity.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTNIST
5.5 MEDIUM
LOCAL
LOW
LOW
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
LinuxCNA
---
---
CISA-ADPADP
---
---
CVEADP
---
---
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
VendorProductVersion
linuxlinux_kernel
4.4.245 ≤
𝑥
< 4.4.269
linuxlinux_kernel
4.9.245 ≤
𝑥
< 4.9.269
linuxlinux_kernel
4.14.208 ≤
𝑥
< 4.14.233
linuxlinux_kernel
4.19.159 ≤
𝑥
< 4.19.191
linuxlinux_kernel
5.4.79 ≤
𝑥
< 5.4.120
linuxlinux_kernel
5.10 ≤
𝑥
< 5.10.38
linuxlinux_kernel
5.11 ≤
𝑥
< 5.11.22
linuxlinux_kernel
5.12 ≤
𝑥
< 5.12.5
linuxlinux_kernel
5.13:rc1
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
linux
bullseye
5.10.223-1
fixed
bullseye (security)
5.10.226-1
fixed
bookworm
6.1.106-3
fixed
bookworm (security)
6.1.112-1
fixed
trixie
6.11.5-1
fixed
sid
6.11.6-1
fixed
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
linux
noble
not-affected
mantic
not-affected
jammy
not-affected
focal
Fixed 5.4.0-80.90
released
bionic
pending
xenial
Fixed 4.4.0-253.287
released
trusty
not-affected
linux-allwinner-5.19
noble
dne
mantic
dne
jammy
ignored
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-aws
noble
not-affected
mantic
not-affected
jammy
not-affected
focal
Fixed 5.4.0-1054.57
released
bionic
pending
xenial
Fixed 4.4.0-1168.183
released
trusty
Fixed 4.4.0-1130.136
released
linux-aws-5.0
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
ignored
xenial
dne
trusty
dne
linux-aws-5.11
noble
dne
mantic
dne
jammy
dne
focal
ignored
bionic
dne
xenial
dne
trusty
dne
linux-aws-5.13
noble
dne
mantic
dne
jammy
dne
focal
ignored
bionic
dne
xenial
dne
trusty
dne
linux-aws-5.15
noble
dne
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jammy
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focal
not-affected
bionic
dne
xenial
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linux-aws-5.19
noble
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linux-aws-5.3
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linux-aws-5.4
noble
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bionic
pending
xenial
dne
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linux-aws-5.8
noble
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ignored
bionic
dne
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linux-aws-6.2
noble
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ignored
focal
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linux-aws-6.5
noble
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not-affected
focal
dne
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dne
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linux-aws-fips
noble
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linux-aws-hwe
noble
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dne
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Fixed 4.15.0-1109.116~16.04.1
released
trusty
dne
linux-azure
noble
not-affected
mantic
not-affected
jammy
not-affected
focal
Fixed 5.4.0-1055.57
released
bionic
ignored
xenial
Fixed 4.15.0-1121.134~16.04.1
released
trusty
Fixed 4.15.0-1121.134~14.04.1
released
linux-azure-4.15
noble
dne
mantic
dne
jammy
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focal
dne
bionic
pending
xenial
dne
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linux-azure-5.11
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linux-azure-5.13
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dne
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linux-azure-5.15
noble
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not-affected
bionic
dne
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dne
trusty
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linux-azure-5.19
noble
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linux-azure-5.3
noble
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ignored
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linux-azure-5.4
noble
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pending
xenial
dne
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linux-azure-5.8
noble
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ignored
bionic
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linux-azure-6.2
noble
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focal
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dne
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linux-azure-6.5
noble
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focal
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dne
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trusty
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linux-azure-edge
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ignored
xenial
dne
trusty
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linux-azure-fde
noble
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mantic
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jammy
not-affected
focal
ignored
bionic
dne
xenial
dne
trusty
dne
linux-azure-fde-5.15
noble
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mantic
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jammy
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focal
not-affected
bionic
dne
xenial
dne
trusty
dne
linux-azure-fde-5.19
noble
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ignored
focal
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bionic
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xenial
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linux-azure-fde-6.2
noble
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ignored
focal
dne
bionic
dne
xenial
dne
trusty
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linux-azure-fips
noble
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jammy
dne
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-bluefield
noble
dne
mantic
dne
jammy
dne
focal
Fixed 5.4.0-1016.19
released
bionic
dne
xenial
dne
trusty
dne
linux-dell300x
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
ignored
xenial
dne
trusty
dne
linux-fips
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
dne
xenial
ignored
trusty
ignored
linux-gcp
noble
not-affected
mantic
not-affected
jammy
not-affected
focal
Fixed 5.4.0-1049.53
released
bionic
ignored
xenial
Fixed 4.15.0-1106.120~16.04.1
released
trusty
dne
linux-gcp-4.15
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
pending
xenial
dne
trusty
dne
linux-gcp-5.11
noble
dne
mantic
dne
jammy
dne
focal
ignored
bionic
dne
xenial
dne
trusty
dne
linux-gcp-5.13
noble
dne
mantic
dne
jammy
dne
focal
ignored
bionic
dne
xenial
dne
trusty
dne
linux-gcp-5.15
noble
dne
mantic
dne
jammy
dne
focal
not-affected
bionic
dne
xenial
dne
trusty
dne
linux-gcp-5.19
noble
dne
mantic
dne
jammy
ignored
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-gcp-5.3
noble
dne
mantic
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jammy
dne
focal
dne
bionic
ignored
xenial
dne
trusty
dne
linux-gcp-5.4
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
pending
xenial
dne
trusty
dne
linux-gcp-5.8
noble
dne
mantic
dne
jammy
dne
focal
ignored
bionic
dne
xenial
dne
trusty
dne
linux-gcp-6.2
noble
dne
mantic
dne
jammy
ignored
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-gcp-6.5
noble
dne
mantic
dne
jammy
not-affected
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-gcp-fips
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-gke
noble
not-affected
mantic
dne
jammy
not-affected
focal
ignored
bionic
dne
xenial
ignored
trusty
dne
linux-gke-4.15
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
ignored
xenial
dne
trusty
dne
linux-gke-5.0
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
ignored
xenial
dne
trusty
dne
linux-gke-5.15
noble
dne
mantic
dne
jammy
dne
focal
ignored
bionic
dne
xenial
dne
trusty
dne
linux-gke-5.3
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
ignored
xenial
dne
trusty
dne
linux-gke-5.4
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
ignored
xenial
dne
trusty
dne
linux-gkeop
noble
dne
mantic
dne
jammy
not-affected
focal
Fixed 5.4.0-1021.22
released
bionic
dne
xenial
dne
trusty
dne
linux-gkeop-5.15
noble
dne
mantic
dne
jammy
dne
focal
not-affected
bionic
dne
xenial
dne
trusty
dne
linux-gkeop-5.4
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
ignored
xenial
dne
trusty
dne
linux-hwe
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
ignored
xenial
Fixed 4.15.0-151.157~16.04.1
released
trusty
dne
linux-hwe-5.11
noble
dne
mantic
dne
jammy
dne
focal
ignored
bionic
dne
xenial
dne
trusty
dne
linux-hwe-5.13
noble
dne
mantic
dne
jammy
dne
focal
ignored
bionic
dne
xenial
dne
trusty
dne
linux-hwe-5.15
noble
dne
mantic
dne
jammy
dne
focal
not-affected
bionic
dne
xenial
dne
trusty
dne
linux-hwe-5.19
noble
dne
mantic
dne
jammy
ignored
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-hwe-5.4
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
pending
xenial
dne
trusty
dne
linux-hwe-5.8
noble
dne
mantic
dne
jammy
dne
focal
ignored
bionic
dne
xenial
dne
trusty
dne
linux-hwe-6.2
noble
dne
mantic
dne
jammy
ignored
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-hwe-6.5
noble
dne
mantic
dne
jammy
not-affected
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-hwe-6.8
noble
dne
jammy
not-affected
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-hwe-edge
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
ignored
xenial
ignored
trusty
dne
linux-ibm
noble
not-affected
mantic
ignored
jammy
not-affected
focal
not-affected
bionic
dne
xenial
dne
trusty
dne
linux-ibm-5.15
noble
dne
mantic
dne
jammy
dne
focal
not-affected
bionic
dne
xenial
dne
trusty
dne
linux-ibm-5.4
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
not-affected
xenial
dne
trusty
dne
linux-intel
noble
not-affected
mantic
dne
jammy
dne
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-intel-5.13
noble
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mantic
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jammy
dne
focal
ignored
bionic
dne
xenial
dne
trusty
dne
linux-intel-iot-realtime
noble
dne
jammy
dne
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-intel-iotg
noble
dne
mantic
dne
jammy
not-affected
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-intel-iotg-5.15
noble
dne
mantic
dne
jammy
dne
focal
not-affected
bionic
dne
xenial
dne
trusty
dne
linux-iot
noble
dne
mantic
dne
jammy
dne
focal
not-affected
bionic
dne
xenial
dne
trusty
dne
linux-kvm
noble
dne
mantic
dne
jammy
not-affected
focal
Fixed 5.4.0-1044.46
released
bionic
pending
xenial
Fixed 4.4.0-1131.141
released
trusty
dne
linux-laptop
noble
dne
mantic
not-affected
jammy
dne
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-lowlatency
noble
not-affected
mantic
not-affected
jammy
not-affected
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-lowlatency-hwe-5.15
noble
dne
mantic
dne
jammy
dne
focal
not-affected
bionic
dne
xenial
dne
trusty
dne
linux-lowlatency-hwe-5.19
noble
dne
mantic
dne
jammy
ignored
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-lowlatency-hwe-6.2
noble
dne
mantic
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jammy
ignored
focal
dne
bionic
dne
xenial
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trusty
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linux-lowlatency-hwe-6.5
noble
dne
mantic
dne
jammy
not-affected
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-lowlatency-hwe-6.8
noble
dne
jammy
not-affected
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-lts-xenial
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
dne
xenial
dne
trusty
Fixed 4.4.0-253.287~14.04.1
released
linux-nvidia
noble
not-affected
mantic
dne
jammy
not-affected
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-nvidia-6.2
noble
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mantic
dne
jammy
ignored
focal
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bionic
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linux-nvidia-6.5
noble
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focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-nvidia-6.8
noble
dne
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not-affected
focal
dne
bionic
dne
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dne
trusty
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linux-nvidia-lowlatency
noble
not-affected
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focal
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bionic
dne
xenial
dne
trusty
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linux-oem
noble
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mantic
dne
jammy
dne
focal
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ignored
xenial
ignored
trusty
dne
linux-oem-5.10
noble
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jammy
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focal
ignored
bionic
dne
xenial
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dne
linux-oem-5.13
noble
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jammy
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focal
ignored
bionic
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trusty
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linux-oem-5.14
noble
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mantic
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jammy
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focal
ignored
bionic
dne
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linux-oem-5.17
noble
dne
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jammy
ignored
focal
dne
bionic
dne
xenial
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dne
linux-oem-5.6
noble
dne
mantic
dne
jammy
dne
focal
ignored
bionic
dne
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trusty
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linux-oem-6.0
noble
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mantic
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ignored
focal
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dne
xenial
dne
trusty
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linux-oem-6.1
noble
dne
mantic
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jammy
ignored
focal
dne
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dne
xenial
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trusty
dne
linux-oem-6.5
noble
dne
mantic
dne
jammy
not-affected
focal
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bionic
dne
xenial
dne
trusty
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linux-oem-6.8
noble
not-affected
mantic
dne
jammy
dne
focal
dne
bionic
dne
xenial
dne
trusty
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linux-oem-osp1
noble
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mantic
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focal
dne
bionic
ignored
xenial
dne
trusty
dne
linux-oracle
noble
not-affected
mantic
not-affected
jammy
not-affected
focal
Fixed 5.4.0-1052.56
released
bionic
pending
xenial
Fixed 4.15.0-1078.86~16.04.1
released
trusty
dne
linux-oracle-5.0
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
ignored
xenial
dne
trusty
dne
linux-oracle-5.11
noble
dne
mantic
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ignored
bionic
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linux-oracle-5.13
noble
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focal
ignored
bionic
dne
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trusty
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linux-oracle-5.15
noble
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mantic
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jammy
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focal
not-affected
bionic
dne
xenial
dne
trusty
dne
linux-oracle-5.3
noble
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focal
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bionic
ignored
xenial
dne
trusty
dne
linux-oracle-5.4
noble
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mantic
dne
jammy
dne
focal
dne
bionic
pending
xenial
dne
trusty
dne
linux-oracle-5.8
noble
dne
mantic
dne
jammy
dne
focal
ignored
bionic
dne
xenial
dne
trusty
dne
linux-oracle-6.5
noble
dne
mantic
dne
jammy
not-affected
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-raspi
noble
not-affected
mantic
not-affected
jammy
not-affected
focal
Fixed 5.4.0-1041.45
released
bionic
dne
xenial
dne
trusty
dne
linux-raspi-5.4
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
pending
xenial
dne
trusty
dne
linux-raspi-realtime
noble
dne
jammy
dne
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-raspi2
noble
dne
mantic
dne
jammy
dne
focal
ignored
bionic
ignored
xenial
ignored
trusty
dne
linux-raspi2-5.3
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
ignored
xenial
dne
trusty
dne
linux-realtime
noble
dne
jammy
ignored
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-riscv
noble
not-affected
mantic
not-affected
jammy
ignored
focal
ignored
bionic
dne
xenial
dne
trusty
dne
linux-riscv-5.11
noble
dne
mantic
dne
jammy
dne
focal
ignored
bionic
dne
xenial
dne
trusty
dne
linux-riscv-5.15
noble
dne
mantic
dne
jammy
dne
focal
not-affected
bionic
dne
xenial
dne
trusty
dne
linux-riscv-5.19
noble
dne
mantic
dne
jammy
ignored
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-riscv-5.8
noble
dne
mantic
dne
jammy
dne
focal
ignored
bionic
dne
xenial
dne
trusty
dne
linux-riscv-6.5
noble
dne
mantic
dne
jammy
not-affected
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-riscv-6.8
noble
dne
jammy
not-affected
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-snapdragon
noble
dne
mantic
dne
jammy
dne
focal
dne
bionic
ignored
xenial
ignored
trusty
dne
linux-starfive
noble
dne
mantic
not-affected
jammy
dne
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-starfive-5.19
noble
dne
mantic
dne
jammy
ignored
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-starfive-6.2
noble
dne
mantic
dne
jammy
ignored
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-starfive-6.5
noble
dne
mantic
dne
jammy
not-affected
focal
dne
bionic
dne
xenial
dne
trusty
dne
linux-xilinx-zynqmp
noble
dne
mantic
dne
jammy
not-affected
focal
not-affected
bionic
dne
xenial
dne
trusty
dne