In the Linux kernel, the following vulnerability has been resolved: f2fs: fix incorrect FI_NO_EXTENT handling in __destroy_extent_node() When… (CVE-2026-63812)
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix incorrect FI_NO_EXTENT handling in __destroy_extent_node() When __destroy_extent_node() sets the inode flag FI_NO_EXTENT, it does not reset the length of the largest extent to 0 and update the inode folio. Since modifications to the extent tree are disallowed afterward, the cached largest extent may become stale. This can trigger the following error in xfstests generic/388: F2FS-fs (dm-0): sanity_check_extent_cache: inode (ino=1761) extent info [220057, 57, 6] is incorrect, run fsck to fix In the f2fs_drop_inode path, __destroy_extent_node() does not need to guarantee that et->node_cnt is 0, because concurrency with writeback is expected in this path, and writeback may update the extent cache. This patch reverts commit ed78aeebef05 ("f2fs: fix node_cnt race between extent node destroy and writeback"), and remove the unnecessary zero check of et->node_cnt.
AI Analysis
Technical Summary
The Linux kernel's f2fs filesystem had a flaw in __destroy_extent_node() where setting the FI_NO_EXTENT inode flag did not reset the largest extent length or update the inode folio, causing stale extent cache data. This could trigger filesystem sanity check errors, such as those seen in xfstests generic/388. The patch reverts a prior commit related to node count race conditions and removes an unnecessary zero check on et->node_cnt, correcting the extent cache handling during inode destruction and writeback concurrency.
Potential Impact
The vulnerability could cause stale extent cache information in the f2fs filesystem, leading to filesystem errors and requiring filesystem checks (fsck) to fix. There is no indication of direct security compromise or exploitation in the wild.
Mitigation Recommendations
A patch has been applied to the Linux kernel to fix the incorrect handling of the FI_NO_EXTENT flag in __destroy_extent_node(). Users should update to the fixed kernel version once available. Patch status is not explicitly confirmed in the provided data, so check the vendor advisory for current remediation guidance.
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix incorrect FI_NO_EXTENT handling in __destroy_extent_node() When… (CVE-2026-63812)
Description
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix incorrect FI_NO_EXTENT handling in __destroy_extent_node() When __destroy_extent_node() sets the inode flag FI_NO_EXTENT, it does not reset the length of the largest extent to 0 and update the inode folio. Since modifications to the extent tree are disallowed afterward, the cached largest extent may become stale. This can trigger the following error in xfstests generic/388: F2FS-fs (dm-0): sanity_check_extent_cache: inode (ino=1761) extent info [220057, 57, 6] is incorrect, run fsck to fix In the f2fs_drop_inode path, __destroy_extent_node() does not need to guarantee that et->node_cnt is 0, because concurrency with writeback is expected in this path, and writeback may update the extent cache. This patch reverts commit ed78aeebef05 ("f2fs: fix node_cnt race between extent node destroy and writeback"), and remove the unnecessary zero check of et->node_cnt.
CVSS v3.1
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel's f2fs filesystem had a flaw in __destroy_extent_node() where setting the FI_NO_EXTENT inode flag did not reset the largest extent length or update the inode folio, causing stale extent cache data. This could trigger filesystem sanity check errors, such as those seen in xfstests generic/388. The patch reverts a prior commit related to node count race conditions and removes an unnecessary zero check on et->node_cnt, correcting the extent cache handling during inode destruction and writeback concurrency.
Potential Impact
The vulnerability could cause stale extent cache information in the f2fs filesystem, leading to filesystem errors and requiring filesystem checks (fsck) to fix. There is no indication of direct security compromise or exploitation in the wild.
Mitigation Recommendations
A patch has been applied to the Linux kernel to fix the incorrect handling of the FI_NO_EXTENT flag in __destroy_extent_node(). Users should update to the fixed kernel version once available. Patch status is not explicitly confirmed in the provided data, so check the vendor advisory for current remediation guidance.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-7w3g-6v3x-44mp
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-63812"]
- Ecosystems
- []
- Database Specific Severity
- null
- Cvss Version
- null
Threat ID: 6a5d27ad2a4a8d5989131c22
Added to database: 07/19/2026, 19:38:21 UTC
Last enriched: 07/19/2026, 20:21:44 UTC
Last updated: 07/20/2026, 19:41:22 UTC
Views: 11
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