CVE-2026-89686 (GCVE-0-2026-89686)
Vulnerability from cvelistv5
Published
2026-09-11 19:46
Modified
2026-10-21 12:48
Severity ?
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: c5c707f96fc9a6e5a57ca5baac892673270abe3d
Version: c5c707f96fc9a6e5a57ca5baac892673270abe3d
Version: c5c707f96fc9a6e5a57ca5baac892673270abe3d
Version: c5c707f96fc9a6e5a57ca5baac892673270abe3d
Version: c5c707f96fc9a6e5a57ca5baac892673270abe3d
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