btrfs: always detect conflicting inodes when logging inode refs

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-71183
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-01-31 12:16:03 UTC
Updated2026-07-30 06:24:55 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: btrfs: always detect conflicting inodes when logging inode refs After rename exchanging (either with the rename exchange operation or regular renames in multiple non-atomic steps) two inodes and at least one of them is a directory, we can end up with a log tree that contains only of the inodes and after a power failure that can result in an attempt to delete the other inode when it should not because it was not deleted before the power failure. In some case that delete attempt fails when the target inode is a directory that contains a subvolume inside it, since the log replay code is not prepared to deal with directory entries that point to root items (only inode items). 1) We have directories "dir1" (inode A) and "dir2" (inode B) under the same parent directory; 2) We have a file (inode C) under directory "dir1" (inode A); 3) We have a subvolume inside directory "dir2" (inode B); 4) All these inodes were persisted in a past transaction and we are currently at transaction N; 5) We rename the file (inode C), so at btrfs_log_new_name() we update inode C's last_unlink_trans to N; 6) We get a rename exchange for "dir1" (inode A) and "dir2" (inode B), so after the exchange "dir1" is inode B and "dir2" is inode A. During the rename exchange we call btrfs_log_new_name() for inodes A and B, but because they are directories, we don't update their last_unlink_trans to N; 7) An fsync against the file (inode C) is done, and because its inode has a last_unlink_trans with a value of N we log its parent directory (inode A) (through btrfs_log_all_parents(), called from btrfs_log_inode_parent()). 8) So we end up with inode B not logged, which now has the old name of inode A. At copy_inode_items_to_log(), when logging inode A, we did not check if we had any conflicting inode to log because inode A has a generation lower than the current transaction (created in a past transaction); 9) After a power failure, when replaying the log tree, since we find that inode A has a new name that conflicts with the name of inode B in the fs tree, we attempt to delete inode B... this is wrong since that directory was never deleted before the power failure, and because there is a subvolume inside that directory, attempting to delete it will fail since replay_dir_deletes() and btrfs_unlink_inode() are not prepared to deal with dir items that point to roots instead of inodes. When that happens the mount fails and we get a stack trace like the following: [87.2314] BTRFS info (device dm-0): start tree-log replay [87.2318] BTRFS critical (device dm-0): failed to delete reference to subvol, root 5 inode 256 parent 259 [87.2332] ------------[ cut here ]------------ [87.2338] BTRFS: Transaction aborted (error -2) [87.2346] WARNING: CPU: 1 PID: 638968 at fs/btrfs/inode.c:4345 __btrfs_unlink_inode+0x416/0x440 [btrfs] [87.2368] Modules linked in: btrfs loop dm_thin_pool (...) [87.2470] CPU: 1 UID: 0 PID: 638968 Comm: mount Tainted: G W 6.18.0-rc7-btrfs-next-218+ #2 PREEMPT(full) [87.2489] Tainted: [W]=WARN [87.2494] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014 [87.2514] RIP: 0010:__btrfs_unlink_inode+0x416/0x440 [btrfs] [87.2538] Code: c0 89 04 24 (...) [87.2568] RSP: 0018:ffffc0e741f4b9b8 EFLAGS: 00010286 [87.2574] RAX: 0000000000000000 RBX: ffff9d3ec8a6cf60 RCX: 0000000000000000 [87.2582] RDX: 0000000000000002 RSI: ffffffff84ab45a1 RDI: 00000000ffffffff [87.2591] RBP: ffff9d3ec8a6ef20 R08: 0000000000000000 R09: ffffc0e741f4b840 [87.2599] R10: ffff9d45dc1fffa8 R11: 0000000000000003 R12: ffff9d3ee26d77e0 [87.2608] R13: ffffc0e741f4ba98 R14: ffff9d4458040800 R15: ffff9d44b6b7ca10 [87.2618] FS: 00007f7b9603a840(0000) GS:ffff9d4658982000(0000) knlGS:0000000000000000 [87. ---truncated---

Risk And Classification

Primary CVSS: v3.1 5.5 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Problem Types: NVD-CWE-noinfo

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary5.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
3.1CNADECLARED9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 56f23fdbb600e6087db7b009775b95ce07cc3195 c7f0207db68d5a1b4af23acbef1a8e8ddc431ebb git Not specified
CNA Linux Linux affected 56f23fdbb600e6087db7b009775b95ce07cc3195 a63998cd6687c14b160dccb0bbcf281b2eb0dab3 git Not specified
CNA Linux Linux affected 56f23fdbb600e6087db7b009775b95ce07cc3195 0c2413c69129f6ce60157f7b53d9ba880260400b git Not specified
CNA Linux Linux affected 56f23fdbb600e6087db7b009775b95ce07cc3195 d52af58dd463821c5c516aebb031a58934f696ea git Not specified
CNA Linux Linux affected 56f23fdbb600e6087db7b009775b95ce07cc3195 7ba0b6461bc4edb3005ea6e00cdae189bcf908a5 git Not specified
CNA Linux Linux affected 048605483fbdd1e77ead32a7cd7b95cc17eaaf0e git Not specified
CNA Linux Linux affected 033ad030df0ea932a21499582fea59e1df95769b git Not specified
CNA Linux Linux affected 1653a3b0e9436c10eb307c318776cf91fe18ff08 git Not specified
CNA Linux Linux affected ff440e9185e96cbb94481fc8b6192b944dcfc061 git Not specified
CNA Linux Linux affected 3.18.32 3.19 semver Not specified
CNA Linux Linux affected 4.1.23 4.2 semver Not specified
CNA Linux Linux affected 4.4.8 4.5 semver Not specified
CNA Linux Linux affected 4.5.2 4.6 semver Not specified
CNA Linux Linux affected 4.6 Not specified
CNA Linux Linux unaffected 4.6 semver Not specified
CNA Linux Linux unaffected 6.1.161 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.121 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.66 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.6 6.18.* semver Not specified
CNA Linux Linux unaffected 6.19 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/c7f0207db68d5a1b4af23acbef1a8e8ddc431ebb 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/7ba0b6461bc4edb3005ea6e00cdae189bcf908a5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/a63998cd6687c14b160dccb0bbcf281b2eb0dab3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/0c2413c69129f6ce60157f7b53d9ba880260400b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/d52af58dd463821c5c516aebb031a58934f696ea 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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