PT-2026-51921 · Linux · Linux
Published
2026-06-24
·
Updated
2026-06-24
·
CVE-2026-53027
None
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In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: fix missing run load for vcn0 in attr data get block locked()
When a compressed or sparse attribute has its clusters frame-aligned,
vcn is rounded down to the frame start using cmask, which can result
in vcn != vcn0. In this case, vcn and vcn0 may reside in different
attribute segments.
The code already handles the case where vcn is in a different segment
by loading its runs before allocation. However, it fails to load runs
for vcn0 when vcn0 resides in a different segment than vcn. This causes
run lookup entry() to return SPARSE LCN for vcn0 since its segment was
never loaded into the in-memory run list, triggering the WARN ON(1).
Fix this by adding a missing check for vcn0 after the existing vcn
segment check. If vcn0 falls outside the current segment range
[svcn, evcn1), find and load the attribute segment containing vcn0
before performing the run lookup.
The following scenario triggers the bug:
attr data get block locked()
vcn = vcn0 & cmask <- vcn != vcn0 after frame alignment
load runs for vcn segment <- vcn0 segment not loaded!
attr allocate clusters() <- allocation succeeds
run lookup entry(vcn0) <- vcn0 not in run -> SPARSE LCN
WARN ON(1) <- bug fires here!
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Related Identifiers
Affected Products
Linux