FAILED: patch "[PATCH] nfsd: fix stale s2s_cp_stateids IDR entry for async COPY" failed to apply to 6.12-stable tree

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x d0beaee498e11880e72826026db0e9c9890fc114
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026090320-purple-stiffness-b344@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d0beaee498e11880e72826026db0e9c9890fc114 Mon Sep 17 00:00:00 2001
From: Jeff Layton <[email protected]>
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.

index b2f1a9bc9202..b9049a3d7c07 100644
@@ -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, &copy->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;

From: Olga Kornievskaia <[email protected]>

[ Upstream commit 4183cf383b6faec17a0882b84cd2d901dba62b16 ]

When delegated attributes are given on open, the file is opened with NOCMTIME and modifying operations do not update mtime/ctime as to not get out-of-sync with the client's delegated view. However, for COPY operation, the server should update its view of mtime/ctime and reflect that in any GETATTR queries.

[ Stable adaptation: Linux 6.12 does not contain the Fixes commit or nfsd_update_cmtime_attr(), so omit the timestamp-update call sites. Keep the attr_update context needed by d0beaee498e1 ("nfsd: fix stale s2s_cp_stateids IDR entry for async COPY"), and alias its newer error label to the existing 6.12 cleanup path. ]

Stable-dep-of: d0beaee498e1 ("nfsd: fix stale s2s_cp_stateids IDR entry for async COPY")

---
 fs/nfsd/nfs4proc.c | 8 ++++++--
 fs/nfsd/xdr4.h     | 1 +
 2 files changed, 7 insertions(+), 2 deletions(-)

index 2c7a8943cad9c..ee67978996293 100644
@@ -1853,12 +1853,15 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 			goto out_err;
 		async_copy->cp_src = kmalloc(sizeof(*async_copy->cp_src), GFP_KERNEL);
 		if (!async_copy->cp_src)
-			goto out_err;
+			goto out_dec_async_copy_err;
 		if (!nfs4_init_copy_state(nn, copy))
-			goto out_err;
+			goto out_dec_async_copy_err;
 		memcpy(&result->cb_stateid, &copy->cp_stateid.cs_stid,
 			sizeof(result->cb_stateid));
 		dup_copy_fields(copy, async_copy);
+		if ((READ_ONCE(copy->nf_dst->nf_file->f_mode) &
+			       FMODE_NOCMTIME) != 0)
+			async_copy->attr_update = true;
 		async_copy->copy_task = kthread_create(nfsd4_do_async_copy,
 				async_copy, "%s", "copy thread");
 		if (IS_ERR(async_copy->copy_task))

@@ -1877,6 +1880,7 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	trace_nfsd_copy_done(copy, status);
 	release_copy_files(copy);
 	return status;
+out_dec_async_copy_err:
 out_err:
 	if (nfsd4_ssc_is_inter(copy)) {
 		/*

index c75b295df206a..1f62c3755988c 100644
@@ -736,6 +736,7 @@ struct nfsd4_copy {
 
 	struct nfsd_file        *nf_src;
 	struct nfsd_file        *nf_dst;
+	bool			attr_update;
 
 	copy_stateid_t		cp_stateid;
 

2.53.0

From: Jeff Layton <[email protected]>

[ 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.

---
 fs/nfsd/nfs4proc.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

index ee67978996293..d4b47f43b07d8 100644
@@ -1854,11 +1854,12 @@ 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_dec_async_copy_err;
-		if (!nfs4_init_copy_state(nn, copy))
+		dup_copy_fields(copy, async_copy);
+
+		if (!nfs4_init_copy_state(nn, async_copy))
 			goto out_dec_async_copy_err;
-		memcpy(&result->cb_stateid, &copy->cp_stateid.cs_stid,
+		memcpy(&result->cb_stateid, &async_copy->cp_stateid.cs_stid,
 			sizeof(result->cb_stateid));
-		dup_copy_fields(copy, async_copy);
 		if ((READ_ONCE(copy->nf_dst->nf_file->f_mode) &
 			       FMODE_NOCMTIME) != 0)
 			async_copy->attr_update = true;

2.53.0