CVE-2026-89645: btrfs: drop recovered reloc root refs on recovery failure
btrfs: drop recovered reloc root refs on recovery failure
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.12.111-1 - Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 7.2.6-1 - Upgrade
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debian/linux-6.12to a version that resolves this vulnerability.Fixed in 6.12.111-1~deb12u1 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 6.1.191 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 6.6.160 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 6.12.109 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 6.18.50 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 7.2.4 - Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.12.115-2Fixed in 7.2.12-1Fixed in 7.2.15-1 - Upgrade
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debian/linux-6.12to a version that resolves this vulnerability.Fixed in 6.12.113-1~deb12u1 - Upgrade
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ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1
Event History
Frequently Asked Questions
When can this issue be triggered?
It occurs during Btrfs relocation recovery when processing a pending-relocation filesystem image. A failure while loading or adding a later filesystem root, or failure of the first transaction commit, can leave relocation-root references behind.
What conditions make an affected system more likely to encounter the problem?
The described failure paths include an out-of-memory error while processing a later root and an injected failure of the first transaction commit. The issue depends on relocation recovery and an error occurring before relocation roots are merged and dirty subvolumes are cleaned.
How can the affected state be identified?
In the demonstrated first-commit failure case, filesystem roots retained reloc_root pointers while BTRFS_FS_ERROR remained unset. The fault-injection test observed 25 such roots on a pending-relocation image before the fix.
What does the fix change?
On recovery failure, the fix clears the reloc_root pointers for roots associated during recovery and drops their corresponding references. After the first transaction commit succeeds, it drops only temporary filesystem-root references and leaves normal merge and cleanup paths to handle relocation roots.