In the Linux kernel, the following vulnerability has been resolved: ext4: don't cache extent during splitting extent Caching extents during the splitting process is risky, as it may result in stale extents remaining in the status tree. Moreover, in most cases, the corresponding extent block entries are likely already cached before the split happens, making caching here not particularly useful. Assume we have an unwritten extent, and then DIO writes the first half. [UUUUUUUUUUUUUUUU] on-disk extent U: unwritten extent [UUUUUUUUUUUUUUUU] extent status tree |<- ->| ----> dio write this range First, when ext4_split_extent_at() splits this extent, it truncates the existing extent and then inserts a new one. During this process, this extent status entry may be shrunk, and calls to ext4_find_extent() and ext4_cache_extents() may occur, which could potentially insert the truncated range as a hole into the extent status tree. After the split is completed, this hole is not replaced with the correct status. [UUUUUUU|UUUUUUUU] on-disk extent U: unwritten extent [UUUUUUU|HHHHHHHH] extent status tree H: hole Then, the outer calling functions will not correct this remaining hole extent either. Finally, if we perform a delayed buffer write on this latter part, it will re-insert the delayed extent and cause an error in space accounting. In adition, if the unwritten extent cache is not shrunk during the splitting, ext4_cache_extents() also conflicts with existing extents when caching extents. In the future, we will add checks when caching extents, which will trigger a warning. Therefore, Do not cache extents that are being split.
In the Linux kernel, the following vulnerability has been resolved: ext4: don't cache extent during splitting extent Caching extents during the splitting process is risky, as it may result in stale extents remaining in the status tree. Moreover, in most cases, the corresponding extent block entries are likely already cached before the split happens, making caching here not particularly useful. Assume we have an unwritten extent, and then DIO writes the first half. [UUUUUUUUUUUUUUUU] on-disk extent U: unwritten extent [UUUUUUUUUUUUUUUU] extent status tree |<- ->| ----> dio write this range First, when ext4_split_extent_at() splits this extent, it truncates the existing extent and then inserts a new one. During this process, this extent status entry may be shrunk, and calls to ext4_find_extent() and ext4_cache_extents() may occur, which could potentially insert the truncated range as a hole into the extent status tree. After the split is completed, this hole is not replaced with the correct status. [UUUUUUU|UUUUUUUU] on-disk extent U: unwritten extent [UUUUUUU|HHHHHHHH] extent status tree H: hole Then, the outer calling functions will not correct this remaining hole extent either. Finally, if we perform a delayed buffer write on this latter part, it will re-insert the delayed extent and cause an error in space accounting. In adition, if the unwritten extent cache is not shrunk during the splitting, ext4_cache_extents() also conflicts with existing extents when caching extents. In the future, we will add checks when caching extents, which will trigger a warning. Therefore, Do not cache extents that are being split.
Update Linux/Linux to 8302b5b4aacdbb378f7b1216bb2ee782b5142415 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanext4: don't cache extent during splitting extent affects Linux/Linux (generic), Linux/Linux (generic). Severity is medium. In the Linux kernel, the following vulnerability has been resolved: ext4: don't cache extent during splitting extent Caching extents during the splitting process is risky, as it may result in stale extents remaining in the status tree. Moreover, in most cases, the corresponding extent block entries are likely already cached before the split happens, making caching here not particularly useful. Assume we have an unwritten extent, and then DIO writes the first half. [UUUUUUUUUUUUUUUU] on-disk extent U: unwritten extent [UUUUUUUUUUUUUUUU] extent status tree |<- ->| ----> dio write this range First, when ext4_split_extent_at() splits this extent, it truncates the existing extent and then inserts a new one. During this process, this extent status entry may be shrunk, and calls to ext4_find_extent() and ext4_cache_extents() may occur, which could potentially insert the truncated range as a hole into the extent status tree. After the split is completed, this hole is not replaced with the correct status. [UUUUUUU|UUUUUUUU] on-disk extent U: unwritten extent [UUUUUUU|HHHHHHHH] extent status tree H: hole Then, the outer calling functions will not correct this remaining hole extent either. Finally, if we perform a delayed buffer write on this latter part, it will re-insert the delayed extent and cause an error in space accounting. In adition, if the unwritten extent cache is not shrunk during the splitting, ext4_cache_extents() also conflicts with existing extents when caching extents. In the future, we will add checks when caching extents, which will trigger a warning. Therefore, Do not cache extents that are being split.
AI coding agents often install or upgrade packages automatically in generic. A medium vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <8302b5b4aacdbb378f7b1216bb2ee782b5142415 || >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <692103feca376ae4298c92aa8828015d20f1d87b || >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <4c2d9dac4d328244f9365b0a1fa27ec802821820 || >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <93b2ebbbcb2e63cfc21a1946dfe91d3aa7952036 || >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <96007fd3c106aea773c1afae2d6f64cceb6da208 || >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <5b1f4290453314e11cd8e15c7baa8a9b76c19b23 || >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <9a2b95cdaf07785e2739199037bd9c0863ccc1be || >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <8b4b19a2f96348d70bfa306ef7d4a13b0bcbea79 | 8302b5b4aacdbb378f7b1216bb2ee782b5142415, 692103feca376ae4298c92aa8828015d20f1d87b, 4c2d9dac4d328244f9365b0a1fa27ec802821820, 93b2ebbbcb2e63cfc21a1946dfe91d3aa7952036, 96007fd3c106aea773c1afae2d6f64cceb6da208, 5b1f4290453314e11cd8e15c7baa8a9b76c19b23, 9a2b95cdaf07785e2739199037bd9c0863ccc1be, 8b4b19a2f96348d70bfa306ef7d4a13b0bcbea79 |
| Linux/Linuxgeneric | 3.12 | Not reported |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by CVE List V5 (cvelist).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardUpdate Linux/Linux to 8302b5b4aacdbb378f7b1216bb2ee782b5142415 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanext4: don't cache extent during splitting extent affects Linux/Linux (generic), Linux/Linux (generic). Severity is medium. In the Linux kernel, the following vulnerability has been resolved: ext4: don't cache extent during splitting extent Caching extents during the splitting process is risky, as it may result in stale extents remaining in the status tree. Moreover, in most cases, the corresponding extent block entries are likely already cached before the split happens, making caching here not particularly useful. Assume we have an unwritten extent, and then DIO writes the first half. [UUUUUUUUUUUUUUUU] on-disk extent U: unwritten extent [UUUUUUUUUUUUUUUU] extent status tree |<- ->| ----> dio write this range First, when ext4_split_extent_at() splits this extent, it truncates the existing extent and then inserts a new one. During this process, this extent status entry may be shrunk, and calls to ext4_find_extent() and ext4_cache_extents() may occur, which could potentially insert the truncated range as a hole into the extent status tree. After the split is completed, this hole is not replaced with the correct status. [UUUUUUU|UUUUUUUU] on-disk extent U: unwritten extent [UUUUUUU|HHHHHHHH] extent status tree H: hole Then, the outer calling functions will not correct this remaining hole extent either. Finally, if we perform a delayed buffer write on this latter part, it will re-insert the delayed extent and cause an error in space accounting. In adition, if the unwritten extent cache is not shrunk during the splitting, ext4_cache_extents() also conflicts with existing extents when caching extents. In the future, we will add checks when caching extents, which will trigger a warning. Therefore, Do not cache extents that are being split.
AI coding agents often install or upgrade packages automatically in generic. A medium vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <8302b5b4aacdbb378f7b1216bb2ee782b5142415 || >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <692103feca376ae4298c92aa8828015d20f1d87b || >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <4c2d9dac4d328244f9365b0a1fa27ec802821820 || >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <93b2ebbbcb2e63cfc21a1946dfe91d3aa7952036 || >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <96007fd3c106aea773c1afae2d6f64cceb6da208 || >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <5b1f4290453314e11cd8e15c7baa8a9b76c19b23 || >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <9a2b95cdaf07785e2739199037bd9c0863ccc1be || >=107a7bd31ac003e42c0f966aa8e5b26947de6024 <8b4b19a2f96348d70bfa306ef7d4a13b0bcbea79 | 8302b5b4aacdbb378f7b1216bb2ee782b5142415, 692103feca376ae4298c92aa8828015d20f1d87b, 4c2d9dac4d328244f9365b0a1fa27ec802821820, 93b2ebbbcb2e63cfc21a1946dfe91d3aa7952036, 96007fd3c106aea773c1afae2d6f64cceb6da208, 5b1f4290453314e11cd8e15c7baa8a9b76c19b23, 9a2b95cdaf07785e2739199037bd9c0863ccc1be, 8b4b19a2f96348d70bfa306ef7d4a13b0bcbea79 |
| Linux/Linuxgeneric | 3.12 | Not reported |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by CVE List V5 (cvelist).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard