6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeff Layton [ Upstream commit d0beaee498e11880e72826026db0e9c9890fc114 ] For an async COPY, nfsd4_copy() called nfs4_init_copy_state() before dup_copy_fields(), so the s2s_cp_stateids IDR was pointed at &u->copy->cp_stateid -- memory in the per-rqstp COMPOUND buffer that is reused by the next request. dup_copy_fields() copies only the value into async_copy, so the IDR slot dangled at the transient buffer for the whole background copy. Any IDR walker then dereferences reused request memory: the laundromat reads cs_type from it and, if the bytes look like an expired NFS4_COPYNOTIFY_STID, follows into refcount_dec()/idr_remove()/kfree() on garbage; manage_cpntf_state() has the same exposure via idr_find(). Duplicate the fields first, then register the stateid on the stable async_copy. result->cb_stateid is unchanged. Fixes: e0639dc5805a ("NFSD introduce async copy feature") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Jeff Layton Link: https://patch.msgid.link/20260710-nfsd-testing-v3-3-a0ff7db6aa3e@kernel.org Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin --- fs/nfsd/nfs4proc.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 79791ebfc1a30..de32446f58b37 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -1853,11 +1853,14 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, async_copy->cp_src = kmalloc(sizeof(*async_copy->cp_src), GFP_KERNEL); if (!async_copy->cp_src) goto out_err; - if (!nfs4_init_copy_state(nn, copy)) + dup_copy_fields(copy, async_copy); + + if (!nfs4_init_copy_state(nn, async_copy)) goto out_err; - memcpy(&result->cb_stateid, ©->cp_stateid.cs_stid, + memcpy(&result->cb_stateid, &async_copy->cp_stateid.cs_stid, + sizeof(result->cb_stateid)); + memcpy(&async_copy->cp_res.cb_stateid, &result->cb_stateid, sizeof(result->cb_stateid)); - dup_copy_fields(copy, async_copy); async_copy->copy_task = kthread_create(nfsd4_do_async_copy, async_copy, "%s", "copy thread"); if (IS_ERR(async_copy->copy_task)) -- 2.53.0