ext4: fix dirtyclusters double decrement on fs shutdown

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2026-45920
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-27 14:17:06 UTC
Updated2026-05-27 14:48:03 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: ext4: fix dirtyclusters double decrement on fs shutdown fstests test generic/388 occasionally reproduces a warning in ext4_put_super() associated with the dirty clusters count: WARNING: CPU: 7 PID: 76064 at fs/ext4/super.c:1324 ext4_put_super+0x48c/0x590 [ext4] Tracing the failure shows that the warning fires due to an s_dirtyclusters_counter value of -1. IOW, this appears to be a spurious decrement as opposed to some sort of leak. Further tracing of the dirty cluster count deltas and an LLM scan of the resulting output identified the cause as a double decrement in the error path between ext4_mb_mark_diskspace_used() and the caller ext4_mb_new_blocks(). First, note that generic/388 is a shutdown vs. fsstress test and so produces a random set of operations and shutdown injections. In the problematic case, the shutdown triggers an error return from the ext4_handle_dirty_metadata() call(s) made from ext4_mb_mark_context(). The changed value is non-zero at this point, so ext4_mb_mark_diskspace_used() does not exit after the error bubbles up from ext4_mb_mark_context(). Instead, the former decrements both cluster counters and returns the error up to ext4_mb_new_blocks(). The latter falls into the !ar->len out path which decrements the dirty clusters counter a second time, creating the inconsistency. To avoid this problem and simplify ownership of the cluster reservation in this codepath, lift the counter reduction to a single place in the caller. This makes it more clear that ext4_mb_new_blocks() is responsible for acquiring cluster reservation (via ext4_claim_free_clusters()) in the !delalloc case as well as releasing it, regardless of whether it ends up consumed or returned due to failure.

Risk And Classification

EPSS: 0.000240000 probability, percentile 0.073320000 (date 2026-06-01)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 0087d9fb3f29f59e8d42c8b058376d80e5adde4c 523d5a4df3c649fa305c89efb552ec62a1ce9d3d git Not specified
CNA Linux Linux affected 0087d9fb3f29f59e8d42c8b058376d80e5adde4c ca408af08544d96769c93a3d81a7f63f61129e95 git Not specified
CNA Linux Linux affected 0087d9fb3f29f59e8d42c8b058376d80e5adde4c 55576fa14771d33994c29a9ae960e07bb3f56c20 git Not specified
CNA Linux Linux affected 0087d9fb3f29f59e8d42c8b058376d80e5adde4c dbc4e10619ed87a50e637b96f2e574df36a7a769 git Not specified
CNA Linux Linux affected 0087d9fb3f29f59e8d42c8b058376d80e5adde4c 61e372122b6d95aec940fdaea0a16f988f359897 git Not specified
CNA Linux Linux affected 0087d9fb3f29f59e8d42c8b058376d80e5adde4c 3924aea2c33df3864929c1acd178bfc29d8f005f git Not specified
CNA Linux Linux affected 0087d9fb3f29f59e8d42c8b058376d80e5adde4c 81982a11406c5da6c6e2b188028e7056e16b7128 git Not specified
CNA Linux Linux affected 0087d9fb3f29f59e8d42c8b058376d80e5adde4c 94a8cea54cd935c54fa2fba70354757c0fc245e3 git Not specified
CNA Linux Linux affected 2.6.29 Not specified
CNA Linux Linux unaffected 2.6.29 semver Not specified
CNA Linux Linux unaffected 5.10.253 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.203 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.167 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.130 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.75 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.14 6.18.* semver Not specified
CNA Linux Linux unaffected 6.19.4 6.19.* semver Not specified
CNA Linux Linux unaffected 7.0 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/81982a11406c5da6c6e2b188028e7056e16b7128 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/61e372122b6d95aec940fdaea0a16f988f359897 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/55576fa14771d33994c29a9ae960e07bb3f56c20 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/3924aea2c33df3864929c1acd178bfc29d8f005f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ca408af08544d96769c93a3d81a7f63f61129e95 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/94a8cea54cd935c54fa2fba70354757c0fc245e3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/dbc4e10619ed87a50e637b96f2e574df36a7a769 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/523d5a4df3c649fa305c89efb552ec62a1ce9d3d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
© CVE.report 2026 |

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report