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OpenAdvisories
High · 7.8 CVE-2024-26958 EUVD-2024-24220GHSA-5xmm-chg9-ppmr

nfs: fix UAF in direct writes

Published May 1, 2024 · Updated Oct 15, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: linux Package: linux Package: linux-allwinner-5.19 Package: linux-aws Package: linux-aws-5.0 Package: linux-aws-5.11 Package: linux-aws-5.13 Package: linux-aws-5.15 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.4 Package: linux-aws-5.8 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-aws-fips Package: linux-aws-hwe Package: linux-azure Package: linux-azure-4.15 Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.15 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.4 Package: linux-azure-5.8 Package: linux-azure-6.2 Package: linux-azure-6.5 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.2 Package: linux-azure-fips Package: linux-bluefield Package: linux-fips Package: linux-gcp Package: linux-gcp-4.15 Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.15 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.4 Package: linux-gcp-5.8 Package: linux-gcp-6.2 Package: linux-gcp-6.5 Package: linux-gcp-fips Package: linux-gke Package: linux-gke-4.15 Package: linux-gke-5.15 Package: linux-gke-5.4 Package: linux-gkeop Package: linux-gkeop-5.15 Package: linux-gkeop-5.4 Package: linux-hwe Package: linux-hwe-5.11 Package: linux-hwe-5.13 Package: linux-hwe-5.15 Package: linux-hwe-5.19 Package: linux-hwe-5.4 Package: linux-hwe-5.8 Package: linux-hwe-6.2 Package: linux-hwe-6.5 Package: linux-hwe-edge Package: linux-ibm Package: linux-ibm-5.15 Package: linux-ibm-5.4 Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-intel-iotg Package: linux-intel-iotg-5.15 Package: linux-iot Package: linux-kvm Package: linux-lowlatency Package: linux-lowlatency-hwe-5.15 Package: linux-lowlatency-hwe-5.19 Package: linux-lowlatency-hwe-6.2 Package: linux-lowlatency-hwe-6.5 Package: linux-nvidia Package: linux-nvidia-6.2 Package: linux-nvidia-6.5 Package: linux-nvidia-tegra Package: linux-nvidia-tegra-5.15 Package: linux-nvidia-tegra-igx Package: linux-oem Package: linux-oem-5.10 Package: linux-oem-5.13 Package: linux-oem-5.14 Package: linux-oem-5.17 Package: linux-oem-5.6 Package: linux-oem-6.0 Package: linux-oem-6.1 Package: linux-oem-6.5 Package: linux-oem-6.8 Package: linux-oracle Package: linux-oracle-5.0 Package: linux-oracle-5.11 Package: linux-oracle-5.13 Package: linux-oracle-5.15 Package: linux-oracle-5.3 Package: linux-oracle-5.4 Package: linux-oracle-5.8 Package: linux-oracle-6.5 Package: linux-raspi Package: linux-raspi-5.4 Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-riscv Package: linux-riscv-5.11 Package: linux-riscv-5.15 Package: linux-riscv-5.19 Package: linux-riscv-5.8 Package: linux-riscv-6.5 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Package: linux-starfive-6.5 Package: linux-vmware Package: linux-xilinx-zynqmp Platform: Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

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

nfs: fix UAF in direct writes

In production we have been hitting the following warning consistently

------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 17 PID: 1800359 at lib/refcount.c:28 refcount_warn_saturate+0x9c/0xe0
Workqueue: nfsiod nfs_direct_write_schedule_work [nfs]
RIP: 0010:refcount_warn_saturate+0x9c/0xe0
PKRU: 55555554
Call Trace:
<TASK>
? __warn+0x9f/0x130
? refcount_warn_saturate+0x9c/0xe0
? report_bug+0xcc/0x150
? handle_bug+0x3d/0x70
? exc_invalid_op+0x16/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0x9c/0xe0
nfs_direct_write_schedule_work+0x237/0x250 [nfs]
process_one_work+0x12f/0x4a0
worker_thread+0x14e/0x3b0
? ZSTD_getCParams_internal+0x220/0x220
kthread+0xdc/0x120
? __btf_name_valid+0xa0/0xa0
ret_from_fork+0x1f/0x30

This is because we're completing the nfs_direct_request twice in a row.

The source of this is when we have our commit requests to submit, we
process them and send them off, and then in the completion path for the
commit requests we have

if (nfs_commit_end(cinfo.mds))
nfs_direct_write_complete(dreq);

However since we're submitting asynchronous requests we sometimes have
one that completes before we submit the next one, so we end up calling
complete on the nfs_direct_request twice.

The only other place we use nfs_generic_commit_list() is in
__nfs_commit_inode, which wraps this call in a

nfs_commit_begin();
nfs_commit_end();

Which is a common pattern for this style of completion handling, one
that is also repeated in the direct code with get_dreq()/put_dreq()
calls around where we process events as well as in the completion paths.

Fix this by using the same pattern for the commit requests.

Before with my 200 node rocksdb stress running this warning would pop
every 10ish minutes. With my patch the stress test has been running for
several hours without popping.

Affected products

VendorProductAffectedFixed
Linux Linux 4.5 5.4.297

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 linux 6.7.12-1 —
Debian 13 linux 6.7.12-1 —
Debian 12 linux 6.1.85-1 —
Debian 11 linux 5.10.216-1 DSA-5681-1
Debian 10 linux-5.10 5.10.216-1~deb10u1 DLA-3842-1
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield 5.15.0-1047.49 —
Ubuntu 24.04 LTS linux 6.8.0-35.35 USN-6816-1
Ubuntu 24.04 LTS linux-aws 6.8.0-1009.9 USN-6817-1
Ubuntu 24.04 LTS linux-azure 6.8.0-1008.8 USN-6817-3
Ubuntu 24.04 LTS linux-gcp 6.8.0-1008.9 USN-6817-1
Ubuntu 24.04 LTS linux-gke 6.8.0-1004.7 USN-6817-3
Ubuntu 24.04 LTS linux-ibm +2 6.8.0-1006.6 USN-6878-1, USN-6817-2, USN-6816-1
Ubuntu 24.04 LTS linux-raspi 6.8.0-1005.5 USN-6816-1
Ubuntu 24.04 LTS linux-riscv +1 6.8.0-35.35.1 USN-6816-1
Ubuntu 22.04 LTS linux +1 5.15.0-116.126 USN-6898-2, USN-6898-1
Ubuntu 22.04 LTS linux-aws 5.15.0-1065.71 USN-6898-3
Ubuntu 22.04 LTS linux-azure 5.15.0-1068.77 USN-6917-1
Ubuntu 22.04 LTS linux-azure-fde 5.15.0-1068.77.1 USN-6917-1
Ubuntu 22.04 LTS linux-gcp 5.15.0-1064.72 USN-6898-1
Ubuntu 22.04 LTS linux-gke 5.15.0-1062.68 USN-6898-1
Ubuntu 22.04 LTS linux-gkeop 5.15.0-1048.55 USN-6898-1
Ubuntu 22.04 LTS linux-ibm +1 5.15.0-1058.61 USN-6919-1, USN-6898-1
Ubuntu 22.04 LTS linux-intel-iotg 5.15.0-1060.66 USN-6898-1
Ubuntu 22.04 LTS linux-kvm 5.15.0-1062.67 USN-6898-1
Ubuntu 22.04 LTS linux-nvidia 5.15.0-1060.61 USN-6898-1
Ubuntu 22.04 LTS linux-nvidia-tegra 5.15.0-1026.26 —
Ubuntu 22.04 LTS linux-nvidia-tegra-igx 5.15.0-1015.15 —
Ubuntu 22.04 LTS linux-oracle 5.15.0-1063.69 USN-6898-1
Ubuntu 22.04 LTS linux-riscv +31 No fix yet —
Ubuntu 22.04 LTS linux-xilinx-zynqmp 5.15.0-1035.39 USN-7019-1
Ubuntu 20.04 LTS linux-aws-5.15 5.15.0-1065.71~20.04.1 USN-6898-4
Ubuntu 20.04 LTS linux-azure-5.15 5.15.0-1068.77~20.04.1 USN-6917-1
Ubuntu 20.04 LTS linux-azure-fde-5.15 5.15.0-1068.77~20.04.1.1 USN-6917-1
Ubuntu 20.04 LTS linux-gcp-5.15 5.15.0-1065.73~20.04.1 USN-6927-1
Ubuntu 20.04 LTS linux-gke +27 No fix yet —
Ubuntu 20.04 LTS linux-gkeop-5.15 5.15.0-1048.55~20.04.1 USN-6898-1
Ubuntu 20.04 LTS linux-hwe-5.15 +1 5.15.0-116.126~20.04.1 USN-6898-3, USN-6898-2
Ubuntu 20.04 LTS linux-ibm-5.15 5.15.0-1058.61~20.04.1 USN-6898-2
Ubuntu 20.04 LTS linux-intel-iotg-5.15 5.15.0-1060.66~20.04.1 USN-6898-1
Ubuntu 20.04 LTS linux-nvidia-tegra-5.15 5.15.0-1027.27~20.04.1 —
Ubuntu 20.04 LTS linux-oracle-5.15 5.15.0-1063.69~20.04.1 USN-6898-2
Ubuntu 20.04 LTS linux-riscv-5.15 5.15.0-1061.65~20.04.1 —
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Show 13 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 16.04 LTS linux-hwe-edge No fix yet —
Ubuntu Pro Realtime 24.04 LTS linux-raspi-realtime 6.8.0-2004.4 —
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1002.2 —
Ubuntu Pro Realtime 22.04 LTS linux-intel-iot-realtime 5.15.0-1058.60 —
Ubuntu Pro Realtime 22.04 LTS linux-realtime 5.15.0-1066.74 —
Ubuntu Pro FIPS 20.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-updates 22.04 LTS linux-aws-fips 5.15.0-1065.71+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-azure-fips 5.15.0-1068.77+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips 5.15.0-115.125+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-gcp-fips 5.15.0-1064.72+fips1 —
Ubuntu Pro FIPS-updates 20.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-updates 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-preview 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro 20.04 LTS linux +10 No fix yet —
Ubuntu Pro 18.04 LTS linux +12 No fix yet —
Ubuntu Pro 16.04 LTS linux-gcp +4 No fix yet —
Ubuntu Pro 14.04 LTS linux-azure No fix yet —
ReleasePackageFixed inAdvisory
RHEL 9 bpftool 7.4.0-503.11.1.el9_5 RHSA-2024:9315
RHEL 9 rv +67 5.14.0-503.11.1.el9_5 RHSA-2024:9315
RHEL 8 kernel-rt +12 4.18.0-553.16.1.rt7.357.el8_10 RHSA-2024:5102
RHEL 8 perf +26 4.18.0-553.16.1.el8_10 RHSA-2024:5101

AlmaLinux

Errata ↗
ReleasePackageFixed inAdvisory
AlmaLinux 8 kernel-rt +11 4.18.0-553.16.1.rt7.357.el8_10 ALSA-2024:5102
AlmaLinux 8 perf +24 4.18.0-553.16.1.el8_10 ALSA-2024:5101

Rocky Linux

Errata ↗
ReleasePackageFixed inAdvisory
Rocky Linux 8 kernel 4.18.0-553.16.1.el8_10 RXSA-2024:5101, RLSA-2024:5101
Rocky Linux 8 kernel-rt 4.18.0-553.16.1.rt7.357.el8_10 RLSA-2024:5102
ReleasePackageFixed inAdvisory
SLES 15 SP6 kernel-64kb +3 6.4.0-150600.23.7.3 SUSE-SU-2024:2203-1
SLES 15 SP6 kernel-azure +1 6.4.0-150600.8.5.4 SUSE-SU-2024:2135-1
SLES 15 SP6 kernel-default-base 6.4.0-150600.23.7.3.150600.12.2.7 SUSE-SU-2024:2203-1
SLES 15 SP6 kernel-docs 6.4.0-150600.23.7.4 SUSE-SU-2024:2203-1
SLES 15 SP6 kernel-source 6.4.0-150600.23.7.2 SUSE-SU-2024:2203-1
SLES 15 SP6 kernel-syms 6.4.0-150600.23.7.1 SUSE-SU-2024:2203-1
SLES 15 SP6 kernel-syms-azure 6.4.0-150600.8.5.1 SUSE-SU-2024:2135-1
SLES 15 SP5 kernel-64kb +6 5.14.21-150500.55.68.1 SUSE-SU-2024:2190-1
SLES 15 SP5 kernel-azure +2 5.14.21-150500.33.57.1 SUSE-SU-2024:2019-1
SLES 15 SP5 kernel-default-base 5.14.21-150500.55.68.1.150500.6.31.1 SUSE-SU-2024:2190-1
SLES 12 SP5 kernel-azure +2 4.12.14-16.188.1 SUSE-SU-2024:1979-1
SLES 12 SP5 kernel-docs +4 4.12.14-122.219.1 SUSE-SU-2024:2184-1
Show 9 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 12 SP5 kernel-azure +2 4.12.14-16.188.1 SUSE-SU-2024:1979-1
SLES for SAP 12 SP5 kernel-syms +2 4.12.14-122.219.1 SUSE-SU-2024:2184-1
SLE Real Time 12 SP5 kernel-rt +3 4.12.14-10.188.1 SUSE-SU-2024:1983-1
SLE Micro 6.0 kernel-default-base 6.4.0-17.1.1.51 SUSE-SU-2025:20008-1
SLE Micro 6.0 kernel-rt +1 6.4.0-9.1 SUSE-SU-2025:20028-1
SLE Micro 6.0 kernel-source +2 6.4.0-18.1 SUSE-SU-2025:20008-1
SLE Micro 5.5 kernel-default 5.14.21-150500.55.68.1 SUSE-SU-2024:2190-1
SLE Micro 5.5 kernel-default-base 5.14.21-150500.55.68.1.150500.6.31.1 SUSE-SU-2024:2190-1
SLE Micro 5.5 kernel-rt +1 5.14.21-150500.13.58.1 SUSE-SU-2024:2008-1
SLE Live Patching 15 SP6 kernel-default 6.4.0-150600.23.7.3 SUSE-SU-2024:2203-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6-RT_Update_1 1-150600.1.5.1 SUSE-SU-2024:2973-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_1 1-150600.13.3.7 SUSE-SU-2024:2203-1
SLE Live Patching 15 SP5 kernel-default 5.14.21-150500.55.68.1 SUSE-SU-2024:2190-1
SLE Live Patching 15 SP5 kernel-livepatch-SLE15-SP5_Update_15 +1 1-150500.11.3.1 SUSE-SU-2024:2190-1, SUSE-SU-2024:2008-1
SLE Live Patching 12 SP5 kernel-default 4.12.14-122.219.1 SUSE-SU-2024:2184-1
SLE Live Patching 12 SP5 kgraft-patch-SLE12-SP5_Update_57 1-8.3.1 SUSE-SU-2024:2184-1
SUSE Real Time Module 15 SP6 kernel-rt +3 6.4.0-150600.10.5.1 SUSE-SU-2024:2973-1
SUSE Real Time Module 15 SP5 kernel-rt +3 5.14.21-150500.13.58.1 SUSE-SU-2024:2008-1
ReleasePackageFixed inAdvisory
openSUSE Leap 15.6 dtb-aarch64 +2 6.4.0-150600.23.7.1 SUSE-SU-2024:2203-1
openSUSE Leap 15.6 kernel-64kb +5 6.4.0-150600.23.7.3 SUSE-SU-2024:2203-1
openSUSE Leap 15.6 kernel-azure +1 6.4.0-150600.8.5.4 SUSE-SU-2024:2135-1
openSUSE Leap 15.6 kernel-default-base 6.4.0-150600.23.7.3.150600.12.2.7 SUSE-SU-2024:2203-1
openSUSE Leap 15.6 kernel-docs 6.4.0-150600.23.7.4 SUSE-SU-2024:2203-1
openSUSE Leap 15.6 kernel-rt +3 6.4.0-150600.10.5.1 SUSE-SU-2024:2973-1
openSUSE Leap 15.6 kernel-source 6.4.0-150600.23.7.2 SUSE-SU-2024:2203-1
openSUSE Leap 15.6 kernel-syms-azure 6.4.0-150600.8.5.1 SUSE-SU-2024:2135-1
openSUSE Leap 15.5 dtb-aarch64 +10 5.14.21-150500.55.68.1 SUSE-SU-2024:2190-1
openSUSE Leap 15.5 kernel-azure +2 5.14.21-150500.33.57.1 SUSE-SU-2024:2019-1
openSUSE Leap 15.5 kernel-default-base 5.14.21-150500.55.68.1.150500.6.31.1 SUSE-SU-2024:2190-1
openSUSE Leap 15.5 kernel-rt +3 5.14.21-150500.13.58.1 SUSE-SU-2024:2008-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 kernel-livepatch-6.1.84-99.169 1.0-0.amzn2023 ALAS2023-2024-696
Amazon Linux 2023 perf +14 6.1.84-99.169.amzn2023 ALAS2023-2024-696

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 9 bpftool 7.4.0-503.11.1.el9_5 ELSA-2024-9315
Oracle Linux 9 rv +28 5.14.0-503.11.1.el9_5 ELSA-2024-9315
Oracle Linux 8 perf +19 4.18.0-553.16.1.el8_10 ELSA-2024-5101
Oracle Linux 7 kernel-uek +6 5.4.17-2136.348.3.el8uek ELSA-2025-20663
Oracle Linux 7 kernel-uek-tools 5.4.17-2136.348.3.el7uek ELSA-2025-20663

Advisories 45

References