nfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation revoke
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation revoke nfsd4_alloc_layout_stateid reads fp->fi_deleg_file without holding fi_lock when the parent stateid is a delegation. A concurrent delegation revoke via the laundromat can clear fi_deleg_file under fi_lock, causing nfsd_file_get() to return NULL and triggering the BUG_ON. This race is client-reachable: two NFS clients can trigger it by having one hold a delegation while another opens the same file to force a recall. When the first client doesn't respond to the recall, the laundromat revokes it. A concurrent LAYOUTGET from any client using the delegation stateid hits the race window. Fix this by taking fi_lock around the fi_deleg_file read in the SC_TYPE_DELEG path, matching the locking discipline of the find_any_file() arm, and replacing the BUG_ON with a graceful error return that cleans up the partially-initialized layout stateid.
CVE-2026-89686
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-89686
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "c5c707f96fc9a6e5a57ca5baac892673270abe3d",
"lessThan": "d12af460df27876661707efab3a8532146cb961f",
"versionType": "git"
},
{
"status": "affected",
"version": "c5c707f96fc9a6e5a57ca5baac892673270abe3d",
"lessThan": "c517f27498757e616d2a8fe6d16caad1fee422e6",
"versionType": "git"
},
{
"status": "affected",
"version": "c5c707f96fc9a6e5a57ca5baac892673270abe3d",
"lessThan": "607a56fea772c1f4f4989d8e255dd4f7192d9604",
"versionType": "git"
},
{
"status": "affected",
"version": "c5c707f96fc9a6e5a57ca5baac892673270abe3d",
"lessThan": "97bda8b4284d90897a1f1922e5082ff9e35d7c7e",
"versionType": "git"
},
{
"status": "affected",
"version": "c5c707f96fc9a6e5a57ca5baac892673270abe3d",
"lessThan": "ca94ba36172046be6a694a7986f6931e47ed4d51",
"versionType": "git"
}
],
"programFiles": [
"fs/nfsd/nfs4layouts.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.0"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.109",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.50",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/nfsd/nfs4layouts.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89686
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #46707 · Revision 1
- Added to Heist Feed
- Publisher date