vulnerability
Amazon Linux 2023: CVE-2025-39759: Important priority package update for kernel (Multiple Advisories)
| Severity | CVSS | Published | Added | Modified |
|---|---|---|---|---|
| 5 | (AV:L/AC:L/Au:S/C:N/I:N/A:C) | Sep 11, 2025 | Sep 30, 2025 | Oct 16, 2025 |
Severity
5
CVSS
(AV:L/AC:L/Au:S/C:N/I:N/A:C)
Published
Sep 11, 2025
Added
Sep 30, 2025
Modified
Oct 16, 2025
Description
In the Linux kernel, the following vulnerability has been resolved:
btrfs: qgroup: fix race between quota disable and quota rescan ioctl
There's a race between a task disabling quotas and another running the
rescan ioctl that can result in a use-after-free of qgroup records from
the fs_info->qgroup_tree rbtree.
This happens as follows:
1) Task A enters btrfs_ioctl_quota_rescan() -> btrfs_qgroup_rescan();
2) Task B enters btrfs_quota_disable() and calls
btrfs_qgroup_wait_for_completion(), which does nothing because at that
point fs_info->qgroup_rescan_running is false (it wasn't set yet by
task A);
3) Task B calls btrfs_free_qgroup_config() which starts freeing qgroups
from fs_info->qgroup_tree without taking the lock fs_info->qgroup_lock;
4) Task A enters qgroup_rescan_zero_tracking() which starts iterating
the fs_info->qgroup_tree tree while holding fs_info->qgroup_lock,
but task B is freeing qgroup records from that tree without holding
the lock, resulting in a use-after-free.
Fix this by taking fs_info->qgroup_lock at btrfs_free_qgroup_config().
Also at btrfs_qgroup_rescan() don't start the rescan worker if quotas
were already disabled.
btrfs: qgroup: fix race between quota disable and quota rescan ioctl
There's a race between a task disabling quotas and another running the
rescan ioctl that can result in a use-after-free of qgroup records from
the fs_info->qgroup_tree rbtree.
This happens as follows:
1) Task A enters btrfs_ioctl_quota_rescan() -> btrfs_qgroup_rescan();
2) Task B enters btrfs_quota_disable() and calls
btrfs_qgroup_wait_for_completion(), which does nothing because at that
point fs_info->qgroup_rescan_running is false (it wasn't set yet by
task A);
3) Task B calls btrfs_free_qgroup_config() which starts freeing qgroups
from fs_info->qgroup_tree without taking the lock fs_info->qgroup_lock;
4) Task A enters qgroup_rescan_zero_tracking() which starts iterating
the fs_info->qgroup_tree tree while holding fs_info->qgroup_lock,
but task B is freeing qgroup records from that tree without holding
the lock, resulting in a use-after-free.
Fix this by taking fs_info->qgroup_lock at btrfs_free_qgroup_config().
Also at btrfs_qgroup_rescan() don't start the rescan worker if quotas
were already disabled.
Solutions
amazon-linux-2023-upgrade-bpftoolamazon-linux-2023-upgrade-bpftool6-12amazon-linux-2023-upgrade-bpftool6-12-debuginfoamazon-linux-2023-upgrade-bpftool-debuginfoamazon-linux-2023-upgrade-kernelamazon-linux-2023-upgrade-kernel6-12amazon-linux-2023-upgrade-kernel6-12-debuginfoamazon-linux-2023-upgrade-kernel6-12-debuginfo-common-aarch64amazon-linux-2023-upgrade-kernel6-12-debuginfo-common-x86-64amazon-linux-2023-upgrade-kernel6-12-develamazon-linux-2023-upgrade-kernel6-12-headersamazon-linux-2023-upgrade-kernel6-12-libbpfamazon-linux-2023-upgrade-kernel6-12-libbpf-debuginfoamazon-linux-2023-upgrade-kernel6-12-libbpf-develamazon-linux-2023-upgrade-kernel6-12-libbpf-staticamazon-linux-2023-upgrade-kernel6-12-modules-extraamazon-linux-2023-upgrade-kernel6-12-modules-extra-commonamazon-linux-2023-upgrade-kernel6-12-toolsamazon-linux-2023-upgrade-kernel6-12-tools-debuginfoamazon-linux-2023-upgrade-kernel6-12-tools-develamazon-linux-2023-upgrade-kernel-debuginfoamazon-linux-2023-upgrade-kernel-debuginfo-common-aarch64amazon-linux-2023-upgrade-kernel-debuginfo-common-x86-64amazon-linux-2023-upgrade-kernel-develamazon-linux-2023-upgrade-kernel-headersamazon-linux-2023-upgrade-kernel-libbpfamazon-linux-2023-upgrade-kernel-libbpf-debuginfoamazon-linux-2023-upgrade-kernel-libbpf-develamazon-linux-2023-upgrade-kernel-libbpf-staticamazon-linux-2023-upgrade-kernel-livepatch-6-1-150-174-273amazon-linux-2023-upgrade-kernel-livepatch-6-12-46-66-121amazon-linux-2023-upgrade-kernel-modules-extraamazon-linux-2023-upgrade-kernel-modules-extra-commonamazon-linux-2023-upgrade-kernel-toolsamazon-linux-2023-upgrade-kernel-tools-debuginfoamazon-linux-2023-upgrade-kernel-tools-develamazon-linux-2023-upgrade-perfamazon-linux-2023-upgrade-perf6-12amazon-linux-2023-upgrade-perf6-12-debuginfoamazon-linux-2023-upgrade-perf-debuginfoamazon-linux-2023-upgrade-python3-perfamazon-linux-2023-upgrade-python3-perf6-12amazon-linux-2023-upgrade-python3-perf6-12-debuginfoamazon-linux-2023-upgrade-python3-perf-debuginfo
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