From d0beaee498e11880e72826026db0e9c9890fc114 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Fri, 10 Jul 2026 10:00:07 -0400 Subject: [PATCH] nfsd: fix stale s2s_cp_stateids IDR entry for async COPY 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 --- fs/nfsd/nfs4proc.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index b2f1a9bc9202..b9049a3d7c07 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -2237,11 +2237,12 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, async_copy->cp_src = kmalloc_obj(*async_copy->cp_src); if (!async_copy->cp_src) goto out_dec_async_copy_err; - if (!nfs4_init_copy_state(nn, copy)) - goto out_dec_async_copy_err; - memcpy(&result->cb_stateid, ©->cp_stateid.cs_stid, - sizeof(result->cb_stateid)); dup_copy_fields(copy, async_copy); + + if (!nfs4_init_copy_state(nn, async_copy)) + goto out_dec_async_copy_err; + memcpy(&result->cb_stateid, &async_copy->cp_stateid.cs_stid, + sizeof(result->cb_stateid)); if ((READ_ONCE(copy->nf_dst->nf_file->f_mode) & FMODE_NOCMTIME) != 0) async_copy->attr_update = true;