CVE-2022-50620: f2fs: fix to invalidate dcc->f2fs_issue_discard in error path

Published Dec 8, 2025
·
Updated

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

f2fs: fix to invalidate dcc->f2fsissuediscard in error path

Syzbot reports a NULL pointer dereference issue as below:

refcountadd include/linux/refcount.h:193 [inline] refcountinc include/linux/refcount.h:250 [inline] refcountinc include/linux/refcount.h:267 [inline] gettaskstruct include/linux/sched/task.h:110 [inline] kthreadstop+0x34/0x1c0 kernel/kthread.c:703 f2fsstopdiscardthread+0x3c/0x5c fs/f2fs/segment.c:1638 killf2fssuper+0x5c/0x194 fs/f2fs/super.c:4522 deactivatelockedsuper+0x70/0xe8 fs/super.c:332 deactivatesuper+0xd0/0xd4 fs/super.c:363 cleanupmnt+0x1f8/0x234 fs/namespace.c:1186 cleanupmnt+0x20/0x30 fs/namespace.c:1193 taskworkrun+0xc4/0x14c kernel/taskwork.c:177 exittaskwork include/linux/taskwork.h:38 [inline] doexit+0x26c/0xbe0 kernel/exit.c:795 dogroupexit+0x60/0xe8 kernel/exit.c:925 dosysexitgroup kernel/exit.c:936 [inline] sesysexitgroup kernel/exit.c:934 [inline] wakeupparent+0x0/0x40 kernel/exit.c:934 invokesyscall arch/arm64/kernel/syscall.c:38 [inline] invokesyscall arch/arm64/kernel/syscall.c:52 [inline] el0svccommon+0x138/0x220 arch/arm64/kernel/syscall.c:142 doel0svc+0x48/0x164 arch/arm64/kernel/syscall.c:206 el0svc+0x58/0x150 arch/arm64/kernel/entry-common.c:636 el0t64synchandler+0x84/0xf0 arch/arm64/kernel/entry-common.c:654 el0t64sync+0x18c/0x190 arch/arm64/kernel/entry.S:581

The root cause of this issue is in error path of f2fsstartdiscardthread(), it missed to invalidate dcc->f2fsissuediscard, later kthreadstop() may access invalid pointer.

Affected Software

120 affected componentsFixes available
Linux Linux kernel (f2fs)
ubuntu/linux-hwe-edge*
ubuntu/linux-aws-5.0*
ubuntu/linux-aws-5.3*
ubuntu/linux-azure*
ubuntu/linux-azure-5.3*
ubuntu/linux-azure-edge*
ubuntu/linux-gcp*
ubuntu/linux-gcp-5.3*
ubuntu/linux-gke-4.15*
ubuntu/linux-gke-5.4*
ubuntu/linux-gkeop-5.4*
ubuntu/linux-hwe*
ubuntu/linux-hwe-edge*
ubuntu/linux-oem*
ubuntu/linux-oracle-5.0*
ubuntu/linux-oracle-5.3*
ubuntu/linux-aws-5.15<5.15.0-1033.37~20.04.1
5.15.0-1033.37~20.04.1
ubuntu/linux-azure-5.15<5.15.0-1035.42~20.04.1
5.15.0-1035.42~20.04.1
ubuntu/linux-gcp-5.15<5.15.0-1031.38~20.04.1
5.15.0-1031.38~20.04.1
ubuntu/linux-hwe-5.15<5.15.0-69.76~20.04.1
5.15.0-69.76~20.04.1
ubuntu/linux-intel-iotg-5.15<5.15.0-1027.32~20.04.1
5.15.0-1027.32~20.04.1
ubuntu/linux-lowlatency-hwe-5.15<5.15.0-69.76~20.04.1
5.15.0-69.76~20.04.1
ubuntu/linux-nvidia-tegra-5.15<5.15.0-1014.14~20.04.1
5.15.0-1014.14~20.04.1
ubuntu/linux-oracle-5.15<5.15.0-1032.38~20.04.1
5.15.0-1032.38~20.04.1
ubuntu/linux-riscv-5.15<5.15.0-1030.34~20.04.1
5.15.0-1030.34~20.04.1
ubuntu/linux-aws-5.11*
ubuntu/linux-aws-5.13*
ubuntu/linux-aws-5.8*
ubuntu/linux-azure-5.11*
ubuntu/linux-azure-5.13*
ubuntu/linux-azure-5.8*
ubuntu/linux-azure-fde*
ubuntu/linux-gcp-5.11*
ubuntu/linux-gcp-5.13*
ubuntu/linux-gcp-5.8*
ubuntu/linux-gke*
ubuntu/linux-gke-5.15*
ubuntu/linux-gkeop*
ubuntu/linux-gkeop-5.15*
ubuntu/linux-hwe-5.11*
ubuntu/linux-hwe-5.13*
ubuntu/linux-hwe-5.8*
ubuntu/linux-intel-5.13*
ubuntu/linux-oem-5.10*
ubuntu/linux-oem-5.13*
ubuntu/linux-oem-5.6*
ubuntu/linux-oracle-5.11*
ubuntu/linux-oracle-5.13*
ubuntu/linux-oracle-5.8*
ubuntu/linux-raspi2*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.11*
ubuntu/linux-riscv-5.8*
ubuntu/linux<5.15.0-69.76
5.15.0-69.76
ubuntu/linux-allwinner-5.19*
ubuntu/linux-aws<5.15.0-1033.37
5.15.0-1033.37
ubuntu/linux-aws-5.19*
ubuntu/linux-aws-6.2*
ubuntu/linux-aws-6.5*
ubuntu/linux-azure<5.15.0-1035.42
5.15.0-1035.42
ubuntu/linux-azure-5.19*
ubuntu/linux-azure-6.2*
ubuntu/linux-azure-6.5*
ubuntu/linux-azure-fde<5.15.0-1035.42.1
5.15.0-1035.42.1
ubuntu/linux-azure-fde-5.19*
ubuntu/linux-azure-fde-6.2*
ubuntu/linux-gcp<5.15.0-1031.38
5.15.0-1031.38
ubuntu/linux-gcp-5.19*
ubuntu/linux-gcp-6.2*
ubuntu/linux-gcp-6.5*
ubuntu/linux-gke<5.15.0-1030.35
5.15.0-1030.35
ubuntu/linux-gkeop<5.15.0-1017.22
5.15.0-1017.22
ubuntu/linux-hwe-5.19*
ubuntu/linux-hwe-6.2*
ubuntu/linux-hwe-6.5*
ubuntu/linux-ibm<5.15.0-1027.30
5.15.0-1027.30
ubuntu/linux-intel-iot-realtime*
ubuntu/linux-intel-iotg<5.15.0-1027.32
5.15.0-1027.32
ubuntu/linux-kvm<5.15.0-1030.35
5.15.0-1030.35
ubuntu/linux-lowlatency<5.15.0-69.76
5.15.0-69.76
ubuntu/linux-lowlatency-hwe-5.19*
ubuntu/linux-lowlatency-hwe-6.2*
ubuntu/linux-lowlatency-hwe-6.5*
ubuntu/linux-nvidia<5.15.0-1023.23
5.15.0-1023.23
ubuntu/linux-nvidia-6.2*
ubuntu/linux-nvidia-6.5*
ubuntu/linux-oem-5.17*
ubuntu/linux-oem-6.0*
ubuntu/linux-oem-6.1*
ubuntu/linux-oem-6.5*
ubuntu/linux-oracle<5.15.0-1032.38
5.15.0-1032.38
ubuntu/linux-oracle-6.5*
ubuntu/linux-raspi<5.15.0-1026.28
5.15.0-1026.28
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.19*
ubuntu/linux-riscv-6.5*
ubuntu/linux-starfive-5.19*
ubuntu/linux-starfive-6.2*
ubuntu/linux-starfive-6.5*
ubuntu/linux-bluefield<5.15.0-1015.17
5.15.0-1015.17
ubuntu/linux-intel-iot-realtime<5.15.0-1023.28
5.15.0-1023.28
ubuntu/linux-realtime<5.15.0-1034.37
5.15.0-1034.37
ubuntu/linux-azure-6.11*
ubuntu/linux-gcp-6.11*
ubuntu/linux-hwe-6.11*
ubuntu/linux-lowlatency-hwe-6.11*
ubuntu/linux-nvidia-6.11*
ubuntu/linux-oem-6.11*
ubuntu/linux-oem-6.8*
ubuntu/linux-raspi-realtime*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-6.14*
ubuntu/linux-vmware*
debian/linux<6.1.4-1
6.1.4-1
debian/linux<6.1.4-1
6.1.4-1
debian/linux<6.1.4-1
6.1.4-1
debian/linux
6.1.176-16.1.190-16.12.107-16.12.116-17.2.15-17.3.4-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade ubuntu/linux-aws-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1033.37~20.04.1
  2. Upgrade

    Upgrade ubuntu/linux-azure-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1035.42~20.04.1
  3. Upgrade

    Upgrade ubuntu/linux-gcp-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1031.38~20.04.1
  4. Upgrade

    Upgrade ubuntu/linux-hwe-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-69.76~20.04.1
  5. Upgrade

    Upgrade ubuntu/linux-intel-iotg-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1027.32~20.04.1
  6. Upgrade

    Upgrade ubuntu/linux-lowlatency-hwe-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-69.76~20.04.1
  7. Upgrade

    Upgrade ubuntu/linux-nvidia-tegra-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1014.14~20.04.1
  8. Upgrade

    Upgrade ubuntu/linux-oracle-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1032.38~20.04.1
  9. Upgrade

    Upgrade ubuntu/linux-riscv-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1030.34~20.04.1
  10. Upgrade

    Upgrade ubuntu/linux to a version that resolves this vulnerability.

    Fixed in 5.15.0-69.76
  11. Upgrade

    Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.

    Fixed in 5.15.0-1033.37
  12. Upgrade

    Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.

    Fixed in 5.15.0-1035.42
  13. Upgrade

    Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.

    Fixed in 5.15.0-1035.42.1
  14. Upgrade

    Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.

    Fixed in 5.15.0-1031.38
  15. Upgrade

    Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.

    Fixed in 5.15.0-1030.35
  16. Upgrade

    Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.

    Fixed in 5.15.0-1017.22
  17. Upgrade

    Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.

    Fixed in 5.15.0-1027.30
  18. Upgrade

    Upgrade ubuntu/linux-intel-iotg to a version that resolves this vulnerability.

    Fixed in 5.15.0-1027.32
  19. Upgrade

    Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.

    Fixed in 5.15.0-1030.35
  20. Upgrade

    Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.

    Fixed in 5.15.0-69.76
  21. Upgrade

    Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.

    Fixed in 5.15.0-1023.23
  22. Upgrade

    Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.

    Fixed in 5.15.0-1032.38
  23. Upgrade

    Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.

    Fixed in 5.15.0-1026.28
  24. Upgrade

    Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.

    Fixed in 5.15.0-1015.17
  25. Upgrade

    Upgrade ubuntu/linux-intel-iot-realtime to a version that resolves this vulnerability.

    Fixed in 5.15.0-1023.28
  26. Upgrade

    Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.

    Fixed in 5.15.0-1034.37
  27. Upgrade

    Upgrade debian/linux to a version that resolves this vulnerability.

    Fixed in 6.1.4-1
  28. Upgrade

    Upgrade debian/linux to a version that resolves this vulnerability.

    Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.107-1Fixed in 6.12.116-1Fixed in 7.2.15-1Fixed in 7.3.4-1

Event History

Dec 8, 2025
CVE Published
via MITRE·01:16 AM
Data Sourced
via MITRE·01:16 AM
Description
Data Sourced
via OSV·02:15 AM
DescriptionSeverityAffected Software
Data Sourced
via NVD·02:15 AM
Description

Frequently Asked Questions

1

What is the severity of CVE-2022-50620?

CVE-2022-50620 is classified as a medium severity vulnerability due to its potential for causing system instability.

2

How do I fix CVE-2022-50620?

To address CVE-2022-50620, users should update their Linux kernel to the latest stable version that includes the fix.

3

What impact does CVE-2022-50620 have on systems?

CVE-2022-50620 can lead to a NULL pointer dereference, potentially resulting in crashes or unexpected behavior.

4

Which versions of the Linux kernel are affected by CVE-2022-50620?

CVE-2022-50620 affects multiple versions of the Linux kernel prior to the patches that resolve the vulnerability.

5

Is CVE-2022-50620 being actively exploited in the wild?

As of the latest information, there are no confirmed reports of active exploitation of CVE-2022-50620.

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