cbcvebase.
CVE-2025-39884
published 2025-09-23

CVE-2025-39884: In the Linux kernel, the following vulnerability has been resolved: btrfs: fix subvolume deletion lockup caused by inodes xarray race There is a race condition…

PriorityP416medium4.7CVSS 3.1
AVLACHPRLUINSUCNINAH
EPSS
0.10%
0.9th percentile
In the Linux kernel, the following vulnerability has been resolved: btrfs: fix subvolume deletion lockup caused by inodes xarray race There is a race condition between inode eviction and inode caching that can cause a live struct btrfs_inode to be missing from the root->inodes xarray. Specifically, there is a window during evict() between the inode being unhashed and deleted from the xarray. If btrfs_iget() is called for the same inode in that window, it will be recreated and inserted into the xarray, but then eviction will delete the new entry, leaving nothing in the xarray: Thread 1 Thread 2 evict() remove_inode_hash() btrfs_iget_path() btrfs_iget_locked() btrfs_read_locked_inode() btrfs_add_inode_to_root() destroy_inode() btrfs_destroy_inode() btrfs_del_inode_from_root() __xa_erase In turn, this can cause issues for subvolume deletion. Specifically, if an inode is in this lost state, and all other inodes are evicted, then btrfs_del_inode_from_root() will call btrfs_add_dead_root() prematurely. If the lost inode has a delayed_node attached to it, then when btrfs_clean_one_deleted_snapshot() calls btrfs_kill_all_delayed_nodes(), it will loop forever because the delayed_nodes xarray will never become empty (unless memory pressure forces the inode out). We saw this manifest as soft lockups in production. Fix it by only deleting the xarray entry if it matches the given inode (using __xa_cmpxchg()).

Affected

18 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.16.8-1 (forky)linux 6.16.8-1 (forky)
linuxlinux
linuxlinux>= 310b2f5d5a9451b708ab1d3385c3b0998084904c < 9ba898c9fcbe6ebb88bcd4df8aab0f90090d202e9ba898c9fcbe6ebb88bcd4df8aab0f90090d202e
linuxlinux>= 310b2f5d5a9451b708ab1d3385c3b0998084904c < f1498abaf74f8d7b1e7001f16ed77818d8ae6a59f1498abaf74f8d7b1e7001f16ed77818d8ae6a59
linuxlinux>= 310b2f5d5a9451b708ab1d3385c3b0998084904c < f6a6c280059c4ddc23e12e3de1b01098e240036ff6a6c280059c4ddc23e12e3de1b01098e240036f
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.12.48-16.12.48-1
linuxlinux_kernel>= 0 < 6.16.8-16.16.8-1
linuxlinux_kernel>= 6.11 < 6.12.486.12.48
linuxlinux_kernel>= 6.13 < 6.16.86.16.8
msrcazl3_httpd_2.4.58-4_on_azure_linux_3.0
msrcazl3_httpd_2.4.61-1_on_azure_linux_3.0
msrcazure_linux_3.0_arm
msrcazure_linux_3.0_x64
msrccbl2_httpd_2.4.59-1_on_cbl_mariner_2.0
msrccbl2_httpd_2.4.61-1_on_cbl_mariner_2.0
msrccbl_mariner_2.0_arm
msrccbl_mariner_2.0_x64

CVSS provenance

nvdv3.14.7MEDIUMCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
osv4.7MEDIUM
vendor_msrc6.2MEDIUM
vendor_debian4.7LOW
vendor_redhat4.7MEDIUM
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