Wind River Support Network

Description

'In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: decrease sc_count directly if fail to queue dl_recall\n\nA deadlock warning occurred when invoking nfs4_put_stid following a failed\ndl_recall queue operation:\n            T1                            T2\n                                nfs4_laundromat\n                                 nfs4_get_client_reaplist\n                                  nfs4_anylock_blockers\n__break_lease\n spin_lock // ctx->flc_lock\n                                   spin_lock // clp->cl_lock\n                                   nfs4_lockowner_has_blockers\n                                    locks_owner_has_blockers\n                                     spin_lock // flctx->flc_lock\n nfsd_break_deleg_cb\n  nfsd_break_one_deleg\n   nfs4_put_stid\n    refcount_dec_and_lock\n     spin_lock // clp->cl_lock\n\nWhen a file is opened, an nfs4_delegation is allocated with sc_count\ninitialized to 1, and the file_lease holds a reference to the delegation.\nThe file_lease is then associated with the file through kernel_setlease.\n\nThe disassociation is performed in nfsd4_delegreturn via the following\ncall chain:\nnfsd4_delegreturn --> destroy_delegation --> destroy_unhashed_deleg -->\nnfs4_unlock_deleg_lease --> kernel_setlease --> generic_delete_lease\nThe corresponding sc_count reference will be released after this\ndisassociation.\n\nSince nfsd_break_one_deleg executes while holding the flc_lock, the\ndisassociation process becomes blocked when attempting to acquire flc_lock\nin generic_delete_lease. This means:\n1) sc_count in nfsd_break_one_deleg will not be decremented to 0;\n2) The nfs4_put_stid called by nfsd_break_one_deleg will not attempt to\nacquire cl_lock;\n3) Consequently, no deadlock condition is created.\n\nGiven that sc_count in nfsd_break_one_deleg remains non-zero, we can\nsafely perform refcount_dec on sc_count directly. This approach\neffectively avoids triggering deadlock warnings.\n']
CREATE(Triage):(User=myu2) [CVE-2025-37871 (https://nvd.nist.gov/vuln/detail/CVE-2025-37871)