FAILED: patch "[PATCH] sunrpc: defer rq_argp and rq_resp free until after RCU grace" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] sunrpc: defer rq_argp and rq_resp free until after RCU grace" failed to apply to 6.6-stable tree

[gregkh]

The patch below does not apply to the 6.6-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 <stable@vger.kernel.org>.

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-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x c479bde671cbe2f9e152834a8b0eb7c3c295bbaf
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026090350-breeze-repugnant-70de@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

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

From c479bde671cbe2f9e152834a8b0eb7c3c295bbaf Mon Sep 17 00:00:00 2001
From: Jeff Layton <jlayton@kernel.org>
Date: Thu, 11 Jun 2026 16:00:47 -0400
Subject: [PATCH] sunrpc: defer rq_argp and rq_resp free until after RCU grace
 period
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

svc_rqst_free() frees rqstp->rq_argp and rqstp->rq_resp synchronously
via kfree(), but defers the rqstp struct free via kfree_rcu().  After
svc_exit_thread() calls list_del_rcu() and svc_rqst_free(), there is
a window where RCU readers that started before list_del_rcu() can still
traverse the thread list and find the rqstp.  These readers (e.g.
nfsd_nl_rpc_status_get_dumpit()) dereference rqstp->rq_argp, which has
already been freed — a use-after-free.

Fix this by moving the kfree of rq_argp and rq_resp into an explicit
call_rcu() callback alongside the struct free.  Resources not accessed
by RCU readers (bvec, buffer pages, scratch folio, auth_data) remain
synchronously freed.

Fixes: 812443865c5f ("sunrpc: add a rcu_head to svc_rqst and use kfree_rcu to free it")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260611-nfsd-testing-v2-4-5b90e276f2d9@kernel.org
Signed-off-by: Chuck Lever <cel@kernel.org>

diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 86d39610cf0a..dd80a2eaaa74 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -716,6 +716,15 @@ svc_release_buffer(struct svc_rqst *rqstp)
 	}
 }
 
+static void svc_rqst_free_rcu(struct rcu_head *head)
+{
+	struct svc_rqst *rqstp = container_of(head, struct svc_rqst, rq_rcu_head);
+
+	kfree(rqstp->rq_resp);
+	kfree(rqstp->rq_argp);
+	kfree(rqstp);
+}
+
 static void
 svc_rqst_free(struct svc_rqst *rqstp)
 {
@@ -724,10 +733,8 @@ svc_rqst_free(struct svc_rqst *rqstp)
 	svc_release_buffer(rqstp);
 	if (rqstp->rq_scratch_folio)
 		folio_put(rqstp->rq_scratch_folio);
-	kfree(rqstp->rq_resp);
-	kfree(rqstp->rq_argp);
 	kfree(rqstp->rq_auth_data);
-	kfree_rcu(rqstp, rq_rcu_head);
+	call_rcu(&rqstp->rq_rcu_head, svc_rqst_free_rcu);
 }
 
 static struct svc_rqst *

[PATCH 6.6.y 1/7] SUNRPC: move all of xprt handling into svc_xprt_handle()

[Sasha Levin]

From: NeilBrown <neilb@suse.de>

[ Upstream commit e3274026e2ec69eec6ab51bc499e14bb548548d0 ]

svc_xprt_handle() does lots of things itself, but leaves some to the
caller - svc_recv().  This isn't elegant.

Move that code out of svc_recv() into svc_xprt_handle()

Move the calls to svc_xprt_release() from svc_send() and svc_drop()
(the two possible final steps in svc_process()) and from svc_recv() (in
the case where svc_process() wasn't called) into svc_xprt_handle().

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Stable-dep-of: c479bde671cb ("sunrpc: defer rq_argp and rq_resp free until after RCU grace period")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/sunrpc/svc_xprt.c | 53 ++++++++++++++++---------------------------
 1 file changed, 20 insertions(+), 33 deletions(-)

diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 5cfe5c7408b74..5440d6b50efa5 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -784,7 +784,7 @@ static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt
 	svc_xprt_received(newxpt);
 }
 
-static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
+static void svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 {
 	struct svc_serv *serv = rqstp->rq_server;
 	int len = 0;
@@ -825,11 +825,26 @@ static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 			len = xprt->xpt_ops->xpo_recvfrom(rqstp);
 		rqstp->rq_reserved = serv->sv_max_mesg;
 		atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
+		if (len <= 0)
+			goto out;
+
+		trace_svc_xdr_recvfrom(&rqstp->rq_arg);
+
+		clear_bit(XPT_OLD, &xprt->xpt_flags);
+
+		rqstp->rq_chandle.defer = svc_defer;
+
+		if (serv->sv_stats)
+			serv->sv_stats->netcnt++;
+		percpu_counter_inc(&rqstp->rq_pool->sp_messages_arrived);
+		rqstp->rq_stime = ktime_get();
+		svc_process(rqstp);
 	} else
 		svc_xprt_received(xprt);
 
 out:
-	return len;
+	rqstp->rq_res.len = 0;
+	svc_xprt_release(rqstp);
 }
 
 /**
@@ -843,11 +858,9 @@ static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 void svc_recv(struct svc_rqst *rqstp)
 {
 	struct svc_xprt		*xprt = NULL;
-	struct svc_serv		*serv = rqstp->rq_server;
-	int			len;
 
 	if (!svc_alloc_arg(rqstp))
-		goto out;
+		return;
 
 	try_to_freeze();
 	cond_resched();
@@ -855,31 +868,9 @@ void svc_recv(struct svc_rqst *rqstp)
 		goto out;
 
 	xprt = svc_get_next_xprt(rqstp);
-	if (!xprt)
-		goto out;
-
-	len = svc_handle_xprt(rqstp, xprt);
-
-	/* No data, incomplete (TCP) read, or accept() */
-	if (len <= 0)
-		goto out_release;
-
-	trace_svc_xdr_recvfrom(&rqstp->rq_arg);
-
-	clear_bit(XPT_OLD, &xprt->xpt_flags);
-
-	rqstp->rq_chandle.defer = svc_defer;
-
-	if (serv->sv_stats)
-		serv->sv_stats->netcnt++;
-	percpu_counter_inc(&rqstp->rq_pool->sp_messages_arrived);
-	rqstp->rq_stime = ktime_get();
-	svc_process(rqstp);
+	if (xprt)
+		svc_handle_xprt(rqstp, xprt);
 out:
-	return;
-out_release:
-	rqstp->rq_res.len = 0;
-	svc_xprt_release(rqstp);
 }
 EXPORT_SYMBOL_GPL(svc_recv);
 
@@ -889,7 +880,6 @@ EXPORT_SYMBOL_GPL(svc_recv);
 void svc_drop(struct svc_rqst *rqstp)
 {
 	trace_svc_drop(rqstp);
-	svc_xprt_release(rqstp);
 }
 EXPORT_SYMBOL_GPL(svc_drop);
 
@@ -905,8 +895,6 @@ void svc_send(struct svc_rqst *rqstp)
 	int status;
 
 	xprt = rqstp->rq_xprt;
-	if (!xprt)
-		return;
 
 	/* calculate over-all length */
 	xb = &rqstp->rq_res;
@@ -919,7 +907,6 @@ void svc_send(struct svc_rqst *rqstp)
 	status = xprt->xpt_ops->xpo_sendto(rqstp);
 
 	trace_svc_send(rqstp, status);
-	svc_xprt_release(rqstp);
 }
 
 /*
-- 
2.53.0

[PATCH 6.6.y 2/7] SUNRPC: Add a server-side API for retrieving an RPC's pseudoflavor

[Sasha Levin]

From: Chuck Lever <chuck.lever@oracle.com>

[ Upstream commit deb704281f076097b0347116a82edeba96697db1 ]

NFSD will use this new API to determine whether nfsd_splice_read is
safe to use. This avoids the need to add a dependency to NFSD for
CONFIG_SUNRPC_GSS.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Stable-dep-of: c479bde671cb ("sunrpc: defer rq_argp and rq_resp free until after RCU grace period")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/sunrpc/svcauth.h    |  7 ++++++-
 net/sunrpc/auth_gss/svcauth_gss.c |  6 ++++++
 net/sunrpc/svcauth.c              | 16 ++++++++++++++++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/include/linux/sunrpc/svcauth.h b/include/linux/sunrpc/svcauth.h
index 6f90203edbf8d..61c455f1e1f50 100644
--- a/include/linux/sunrpc/svcauth.h
+++ b/include/linux/sunrpc/svcauth.h
@@ -131,8 +131,11 @@ enum svc_auth_status {
  *   This call releases a domain.
  *
  * set_client()
- *   Givens a pending request (struct svc_rqst), finds and assigns
+ *   Given a pending request (struct svc_rqst), finds and assigns
  *   an appropriate 'auth_domain' as the client.
+ *
+ * pseudoflavor()
+ *   Returns RPC_AUTH pseudoflavor in use by @rqstp.
  */
 struct auth_ops {
 	char *	name;
@@ -143,11 +146,13 @@ struct auth_ops {
 	int			(*release)(struct svc_rqst *rqstp);
 	void			(*domain_release)(struct auth_domain *dom);
 	enum svc_auth_status	(*set_client)(struct svc_rqst *rqstp);
+	rpc_authflavor_t	(*pseudoflavor)(struct svc_rqst *rqstp);
 };
 
 struct svc_xprt;
 
 extern enum svc_auth_status svc_authenticate(struct svc_rqst *rqstp);
+extern rpc_authflavor_t svc_auth_flavor(struct svc_rqst *rqstp);
 extern int	svc_authorise(struct svc_rqst *rqstp);
 extern enum svc_auth_status svc_set_client(struct svc_rqst *rqstp);
 extern int	svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops);
diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 49a8623cc1d57..3015839da877f 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -2009,6 +2009,11 @@ svcauth_gss_domain_release(struct auth_domain *dom)
 	call_rcu(&dom->rcu_head, svcauth_gss_domain_release_rcu);
 }
 
+static rpc_authflavor_t svcauth_gss_pseudoflavor(struct svc_rqst *rqstp)
+{
+	return svcauth_gss_flavor(rqstp->rq_gssclient);
+}
+
 static struct auth_ops svcauthops_gss = {
 	.name		= "rpcsec_gss",
 	.owner		= THIS_MODULE,
@@ -2017,6 +2022,7 @@ static struct auth_ops svcauthops_gss = {
 	.release	= svcauth_gss_release,
 	.domain_release = svcauth_gss_domain_release,
 	.set_client	= svcauth_gss_set_client,
+	.pseudoflavor	= svcauth_gss_pseudoflavor,
 };
 
 static int rsi_cache_create_net(struct net *net)
diff --git a/net/sunrpc/svcauth.c b/net/sunrpc/svcauth.c
index aa4429d0b8106..1619211f0960a 100644
--- a/net/sunrpc/svcauth.c
+++ b/net/sunrpc/svcauth.c
@@ -160,6 +160,22 @@ svc_auth_unregister(rpc_authflavor_t flavor)
 }
 EXPORT_SYMBOL_GPL(svc_auth_unregister);
 
+/**
+ * svc_auth_flavor - return RPC transaction's RPC_AUTH flavor
+ * @rqstp: RPC transaction context
+ *
+ * Returns an RPC flavor or GSS pseudoflavor.
+ */
+rpc_authflavor_t svc_auth_flavor(struct svc_rqst *rqstp)
+{
+	struct auth_ops *aops = rqstp->rq_authop;
+
+	if (!aops->pseudoflavor)
+		return aops->flavour;
+	return aops->pseudoflavor(rqstp);
+}
+EXPORT_SYMBOL_GPL(svc_auth_flavor);
+
 /**************************************************
  * 'auth_domains' are stored in a hash table indexed by name.
  * When the last reference to an 'auth_domain' is dropped,
-- 
2.53.0

[PATCH 6.6.y 3/7] sunrpc: refactor pool_mode setting code

[Sasha Levin]

From: Jeff Layton <jlayton@kernel.org>

[ Upstream commit 5f71f3c325534da55dfda487a67208e2e0f0cd1b ]

Allow the pool_mode setting code to be called from internal callers
so we can call it from a new netlink op. Add a new svc_pool_map_get
function to return the current setting. Change the existing module
parameter handling to use the new interfaces under the hood.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Stable-dep-of: c479bde671cb ("sunrpc: defer rq_argp and rq_resp free until after RCU grace period")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/sunrpc/svc.h |  2 +
 net/sunrpc/svc.c           | 85 ++++++++++++++++++++++++++++----------
 2 files changed, 66 insertions(+), 21 deletions(-)

diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 3d8b215f32d5b..d4558fefd9b4e 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -395,6 +395,8 @@ struct svc_procedure {
 /*
  * Function prototypes.
  */
+int sunrpc_set_pool_mode(const char *val);
+int sunrpc_get_pool_mode(char *val, size_t size);
 int svc_rpcb_setup(struct svc_serv *serv, struct net *net);
 void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net);
 int svc_bind(struct svc_serv *serv, struct net *net);
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 4d8d460747164..bf88a955920f2 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -72,57 +72,100 @@ static struct svc_pool_map svc_pool_map = {
 static DEFINE_MUTEX(svc_pool_map_mutex);/* protects svc_pool_map.count only */
 
 static int
-param_set_pool_mode(const char *val, const struct kernel_param *kp)
+__param_set_pool_mode(const char *val, struct svc_pool_map *m)
 {
-	int *ip = (int *)kp->arg;
-	struct svc_pool_map *m = &svc_pool_map;
-	int err;
+	int err, mode;
 
 	mutex_lock(&svc_pool_map_mutex);
 
-	err = -EBUSY;
-	if (m->count)
-		goto out;
-
 	err = 0;
 	if (!strncmp(val, "auto", 4))
-		*ip = SVC_POOL_AUTO;
+		mode = SVC_POOL_AUTO;
 	else if (!strncmp(val, "global", 6))
-		*ip = SVC_POOL_GLOBAL;
+		mode = SVC_POOL_GLOBAL;
 	else if (!strncmp(val, "percpu", 6))
-		*ip = SVC_POOL_PERCPU;
+		mode = SVC_POOL_PERCPU;
 	else if (!strncmp(val, "pernode", 7))
-		*ip = SVC_POOL_PERNODE;
+		mode = SVC_POOL_PERNODE;
 	else
 		err = -EINVAL;
 
+	if (err)
+		goto out;
+
+	if (m->count == 0)
+		m->mode = mode;
+	else if (mode != m->mode)
+		err = -EBUSY;
 out:
 	mutex_unlock(&svc_pool_map_mutex);
 	return err;
 }
 
 static int
-param_get_pool_mode(char *buf, const struct kernel_param *kp)
+param_set_pool_mode(const char *val, const struct kernel_param *kp)
+{
+	struct svc_pool_map *m = kp->arg;
+
+	return __param_set_pool_mode(val, m);
+}
+
+int sunrpc_set_pool_mode(const char *val)
+{
+	return __param_set_pool_mode(val, &svc_pool_map);
+}
+EXPORT_SYMBOL(sunrpc_set_pool_mode);
+
+/**
+ * sunrpc_get_pool_mode - get the current pool_mode for the host
+ * @buf: where to write the current pool_mode
+ * @size: size of @buf
+ *
+ * Grab the current pool_mode from the svc_pool_map and write
+ * the resulting string to @buf. Returns the number of characters
+ * written to @buf (a'la snprintf()).
+ */
+int
+sunrpc_get_pool_mode(char *buf, size_t size)
 {
-	int *ip = (int *)kp->arg;
+	struct svc_pool_map *m = &svc_pool_map;
 
-	switch (*ip)
+	switch (m->mode)
 	{
 	case SVC_POOL_AUTO:
-		return sysfs_emit(buf, "auto\n");
+		return snprintf(buf, size, "auto");
 	case SVC_POOL_GLOBAL:
-		return sysfs_emit(buf, "global\n");
+		return snprintf(buf, size, "global");
 	case SVC_POOL_PERCPU:
-		return sysfs_emit(buf, "percpu\n");
+		return snprintf(buf, size, "percpu");
 	case SVC_POOL_PERNODE:
-		return sysfs_emit(buf, "pernode\n");
+		return snprintf(buf, size, "pernode");
 	default:
-		return sysfs_emit(buf, "%d\n", *ip);
+		return snprintf(buf, size, "%d", m->mode);
 	}
 }
+EXPORT_SYMBOL(sunrpc_get_pool_mode);
+
+static int
+param_get_pool_mode(char *buf, const struct kernel_param *kp)
+{
+	char str[16];
+	int len;
+
+	len = sunrpc_get_pool_mode(str, ARRAY_SIZE(str));
+
+	/* Ensure we have room for newline and NUL */
+	len = min_t(int, len, ARRAY_SIZE(str) - 2);
+
+	/* tack on the newline */
+	str[len] = '\n';
+	str[len + 1] = '\0';
+
+	return sysfs_emit(buf, str);
+}
 
 module_param_call(pool_mode, param_set_pool_mode, param_get_pool_mode,
-		 &svc_pool_map.mode, 0644);
+		  &svc_pool_map, 0644);
 
 /*
  * Detect best pool mapping mode heuristically,
-- 
2.53.0

[PATCH 6.6.y 4/7] SUNRPC: make various functions static, or not exported.

[Sasha Levin]

From: NeilBrown <neilb@suse.de>

[ Upstream commit f2b27e1d72527f94f030b6356b3187576e60885b ]

Various functions are only used within the sunrpc module, and several
are only use in the one file.  So clean up:

These are marked static, and any EXPORT is removed.
  svc_rcpb_setup()
  svc_rqst_alloc()
  svc_rqst_free()  - also moved before first use
  svc_rpcbind_set_version()
  svc_drop() - also moved to svc.c

These are now not EXPORTed, but are not static.
  svc_authenticate()
  svc_sock_update_bufs()

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Stable-dep-of: c479bde671cb ("sunrpc: defer rq_argp and rq_resp free until after RCU grace period")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/sunrpc/svc.h     |  9 -------
 include/linux/sunrpc/svcauth.h |  1 -
 include/linux/sunrpc/svcsock.h |  2 --
 net/sunrpc/sunrpc.h            |  4 +++
 net/sunrpc/svc.c               | 48 ++++++++++++++++++----------------
 net/sunrpc/svc_xprt.c          |  9 -------
 net/sunrpc/svcauth.c           |  1 -
 net/sunrpc/svcsock.c           |  1 -
 8 files changed, 29 insertions(+), 46 deletions(-)

diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index d4558fefd9b4e..e1afc35e961d1 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -397,17 +397,13 @@ struct svc_procedure {
  */
 int sunrpc_set_pool_mode(const char *val);
 int sunrpc_get_pool_mode(char *val, size_t size);
-int svc_rpcb_setup(struct svc_serv *serv, struct net *net);
 void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net);
 int svc_bind(struct svc_serv *serv, struct net *net);
 struct svc_serv *svc_create(struct svc_program *, unsigned int,
 			    int (*threadfn)(void *data));
-struct svc_rqst *svc_rqst_alloc(struct svc_serv *serv,
-					struct svc_pool *pool, int node);
 bool		   svc_rqst_replace_page(struct svc_rqst *rqstp,
 					 struct page *page);
 void		   svc_rqst_release_pages(struct svc_rqst *rqstp);
-void		   svc_rqst_free(struct svc_rqst *);
 void		   svc_exit_thread(struct svc_rqst *);
 struct svc_serv *  svc_create_pooled(struct svc_program *prog,
 				     struct svc_stat *stats,
@@ -443,11 +439,6 @@ int		   svc_generic_rpcbind_set(struct net *net,
 					   u32 version, int family,
 					   unsigned short proto,
 					   unsigned short port);
-int		   svc_rpcbind_set_version(struct net *net,
-					   const struct svc_program *progp,
-					   u32 version, int family,
-					   unsigned short proto,
-					   unsigned short port);
 
 #define	RPC_MAX_ADDRBUFLEN	(63U)
 
diff --git a/include/linux/sunrpc/svcauth.h b/include/linux/sunrpc/svcauth.h
index 61c455f1e1f50..63cf6fb26dcc1 100644
--- a/include/linux/sunrpc/svcauth.h
+++ b/include/linux/sunrpc/svcauth.h
@@ -151,7 +151,6 @@ struct auth_ops {
 
 struct svc_xprt;
 
-extern enum svc_auth_status svc_authenticate(struct svc_rqst *rqstp);
 extern rpc_authflavor_t svc_auth_flavor(struct svc_rqst *rqstp);
 extern int	svc_authorise(struct svc_rqst *rqstp);
 extern enum svc_auth_status svc_set_client(struct svc_rqst *rqstp);
diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h
index 9e6ecc3526e77..01a547fa447cf 100644
--- a/include/linux/sunrpc/svcsock.h
+++ b/include/linux/sunrpc/svcsock.h
@@ -61,8 +61,6 @@ static inline u32 svc_sock_final_rec(struct svc_sock *svsk)
  */
 void		svc_recv(struct svc_rqst *rqstp);
 void		svc_send(struct svc_rqst *rqstp);
-void		svc_drop(struct svc_rqst *);
-void		svc_sock_update_bufs(struct svc_serv *serv);
 int		svc_addsock(struct svc_serv *serv, struct net *net,
 			    const int fd, char *name_return, const size_t len,
 			    const struct cred *cred);
diff --git a/net/sunrpc/sunrpc.h b/net/sunrpc/sunrpc.h
index d4a362c9e4b3b..e3c6e3b63f0ba 100644
--- a/net/sunrpc/sunrpc.h
+++ b/net/sunrpc/sunrpc.h
@@ -36,7 +36,11 @@ static inline int sock_is_loopback(struct sock *sk)
 	return loopback;
 }
 
+struct svc_serv;
+struct svc_rqst;
 int rpc_clients_notifier_register(void);
 void rpc_clients_notifier_unregister(void);
 void auth_domain_cleanup(void);
+void svc_sock_update_bufs(struct svc_serv *serv);
+enum svc_auth_status svc_authenticate(struct svc_rqst *rqstp);
 #endif /* _NET_SUNRPC_SUNRPC_H */
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index bf88a955920f2..b9314d3632550 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -32,6 +32,7 @@
 #include <trace/events/sunrpc.h>
 
 #include "fail.h"
+#include "sunrpc.h"
 
 #define RPCDBG_FACILITY	RPCDBG_SVCDSP
 
@@ -431,7 +432,7 @@ struct svc_pool *svc_pool_for_cpu(struct svc_serv *serv)
 	return &serv->sv_pools[pidx % serv->sv_nrpools];
 }
 
-int svc_rpcb_setup(struct svc_serv *serv, struct net *net)
+static int svc_rpcb_setup(struct svc_serv *serv, struct net *net)
 {
 	int err;
 
@@ -443,7 +444,6 @@ int svc_rpcb_setup(struct svc_serv *serv, struct net *net)
 	svc_unregister(serv, net);
 	return 0;
 }
-EXPORT_SYMBOL_GPL(svc_rpcb_setup);
 
 void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net)
 {
@@ -677,7 +677,20 @@ svc_release_buffer(struct svc_rqst *rqstp)
 			put_page(rqstp->rq_pages[i]);
 }
 
-struct svc_rqst *
+static void
+svc_rqst_free(struct svc_rqst *rqstp)
+{
+	folio_batch_release(&rqstp->rq_fbatch);
+	svc_release_buffer(rqstp);
+	if (rqstp->rq_scratch_page)
+		put_page(rqstp->rq_scratch_page);
+	kfree(rqstp->rq_resp);
+	kfree(rqstp->rq_argp);
+	kfree(rqstp->rq_auth_data);
+	kfree_rcu(rqstp, rq_rcu_head);
+}
+
+static struct svc_rqst *
 svc_rqst_alloc(struct svc_serv *serv, struct svc_pool *pool, int node)
 {
 	struct svc_rqst	*rqstp;
@@ -712,7 +725,6 @@ svc_rqst_alloc(struct svc_serv *serv, struct svc_pool *pool, int node)
 	svc_rqst_free(rqstp);
 	return NULL;
 }
-EXPORT_SYMBOL_GPL(svc_rqst_alloc);
 
 static struct svc_rqst *
 svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node)
@@ -946,24 +958,6 @@ void svc_rqst_release_pages(struct svc_rqst *rqstp)
 	}
 }
 
-/*
- * Called from a server thread as it's exiting. Caller must hold the "service
- * mutex" for the service.
- */
-void
-svc_rqst_free(struct svc_rqst *rqstp)
-{
-	folio_batch_release(&rqstp->rq_fbatch);
-	svc_release_buffer(rqstp);
-	if (rqstp->rq_scratch_page)
-		put_page(rqstp->rq_scratch_page);
-	kfree(rqstp->rq_resp);
-	kfree(rqstp->rq_argp);
-	kfree(rqstp->rq_auth_data);
-	kfree_rcu(rqstp, rq_rcu_head);
-}
-EXPORT_SYMBOL_GPL(svc_rqst_free);
-
 void
 svc_exit_thread(struct svc_rqst *rqstp)
 {
@@ -1113,6 +1107,7 @@ static int __svc_register(struct net *net, const char *progname,
 	return error;
 }
 
+static
 int svc_rpcbind_set_version(struct net *net,
 			    const struct svc_program *progp,
 			    u32 version, int family,
@@ -1123,7 +1118,6 @@ int svc_rpcbind_set_version(struct net *net,
 				version, family, proto, port);
 
 }
-EXPORT_SYMBOL_GPL(svc_rpcbind_set_version);
 
 int svc_generic_rpcbind_set(struct net *net,
 			    const struct svc_program *progp,
@@ -1536,6 +1530,14 @@ svc_process_common(struct svc_rqst *rqstp)
 	goto sendit;
 }
 
+/*
+ * Drop request
+ */
+static void svc_drop(struct svc_rqst *rqstp)
+{
+	trace_svc_drop(rqstp);
+}
+
 /**
  * svc_process - Execute one RPC transaction
  * @rqstp: RPC transaction context
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 5440d6b50efa5..f44bba40fcf76 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -874,15 +874,6 @@ void svc_recv(struct svc_rqst *rqstp)
 }
 EXPORT_SYMBOL_GPL(svc_recv);
 
-/*
- * Drop request
- */
-void svc_drop(struct svc_rqst *rqstp)
-{
-	trace_svc_drop(rqstp);
-}
-EXPORT_SYMBOL_GPL(svc_drop);
-
 /**
  * svc_send - Return reply to client
  * @rqstp: RPC transaction context
diff --git a/net/sunrpc/svcauth.c b/net/sunrpc/svcauth.c
index 1619211f0960a..93d9e949e2652 100644
--- a/net/sunrpc/svcauth.c
+++ b/net/sunrpc/svcauth.c
@@ -98,7 +98,6 @@ enum svc_auth_status svc_authenticate(struct svc_rqst *rqstp)
 	rqstp->rq_authop = aops;
 	return aops->accept(rqstp);
 }
-EXPORT_SYMBOL_GPL(svc_authenticate);
 
 /**
  * svc_set_client - Assign an appropriate 'auth_domain' as the client
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 2c22677563330..e3010eb060930 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -1435,7 +1435,6 @@ void svc_sock_update_bufs(struct svc_serv *serv)
 		set_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags);
 	spin_unlock_bh(&serv->sv_lock);
 }
-EXPORT_SYMBOL_GPL(svc_sock_update_bufs);
 
 /*
  * Initialize socket for RPC use and create svc_sock struct
-- 
2.53.0

[PATCH 6.6.y 5/7] SUNRPC: Introduce xdr_set_scratch_folio()

[Sasha Levin]

From: Anna Schumaker <anna.schumaker@oracle.com>

[ Upstream commit c8a127596edc026e5364a7a609986dcd3999914c ]

This will replace xdr_set_scratch_page() when we switch pages to folios.

Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Stable-dep-of: c479bde671cb ("sunrpc: defer rq_argp and rq_resp free until after RCU grace period")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/sunrpc/xdr.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
index a180482dc209b..36a974baa101b 100644
--- a/include/linux/sunrpc/xdr.h
+++ b/include/linux/sunrpc/xdr.h
@@ -317,6 +317,19 @@ xdr_set_scratch_page(struct xdr_stream *xdr, struct page *page)
 	xdr_set_scratch_buffer(xdr, page_address(page), PAGE_SIZE);
 }
 
+/**
+ * xdr_set_scratch_folio - Attach a scratch buffer for decoding data
+ * @xdr: pointer to xdr_stream struct
+ * @page: an anonymous folio
+ *
+ * See xdr_set_scratch_buffer().
+ */
+static inline void
+xdr_set_scratch_folio(struct xdr_stream *xdr, struct folio *folio)
+{
+	xdr_set_scratch_buffer(xdr, folio_address(folio), folio_size(folio));
+}
+
 /**
  * xdr_reset_scratch_buffer - Clear scratch buffer information
  * @xdr: pointer to xdr_stream struct
-- 
2.53.0

[PATCH 6.6.y 6/7] SUNRPC: Update svcxdr_init_decode() to call xdr_set_scratch_folio()

[Sasha Levin]

From: Anna Schumaker <anna.schumaker@oracle.com>

[ Upstream commit d57e43b72bf2071caac90da323849c3983a695f0 ]

The only snag here is that __folio_alloc_node() doesn't handle
NUMA_NO_NODE, so I also need to update svc_pool_map_get_node() to return
numa_mem_id() instead. I arrived at this approach by  looking at what
other users of __folio_alloc_node() do for this case.

Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Stable-dep-of: c479bde671cb ("sunrpc: defer rq_argp and rq_resp free until after RCU grace period")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/sunrpc/svc.h |  4 ++--
 net/sunrpc/svc.c           | 10 +++++-----
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index e1afc35e961d1..b9fcacb3902b2 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -206,7 +206,7 @@ struct svc_rqst {
 	struct xdr_buf		rq_arg;
 	struct xdr_stream	rq_arg_stream;
 	struct xdr_stream	rq_res_stream;
-	struct page		*rq_scratch_page;
+	struct folio		*rq_scratch_folio;
 	struct xdr_buf		rq_res;
 	struct page		*rq_pages[RPCSVC_MAXPAGES + 1];
 	struct page *		*rq_respages;	/* points into rq_pages */
@@ -469,7 +469,7 @@ static inline void svcxdr_init_decode(struct svc_rqst *rqstp)
 	buf->len = buf->head->iov_len + buf->page_len + buf->tail->iov_len;
 
 	xdr_init_decode(xdr, buf, argv->iov_base, NULL);
-	xdr_set_scratch_page(xdr, rqstp->rq_scratch_page);
+	xdr_set_scratch_folio(xdr, rqstp->rq_scratch_folio);
 }
 
 /**
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index b9314d3632550..bfd685dfc70e9 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -366,7 +366,7 @@ static int svc_pool_map_get_node(unsigned int pidx)
 		if (m->mode == SVC_POOL_PERNODE)
 			return m->pool_to[pidx];
 	}
-	return NUMA_NO_NODE;
+	return numa_mem_id();
 }
 /*
  * Set the given thread's cpus_allowed mask so that it
@@ -682,8 +682,8 @@ svc_rqst_free(struct svc_rqst *rqstp)
 {
 	folio_batch_release(&rqstp->rq_fbatch);
 	svc_release_buffer(rqstp);
-	if (rqstp->rq_scratch_page)
-		put_page(rqstp->rq_scratch_page);
+	if (rqstp->rq_scratch_folio)
+		folio_put(rqstp->rq_scratch_folio);
 	kfree(rqstp->rq_resp);
 	kfree(rqstp->rq_argp);
 	kfree(rqstp->rq_auth_data);
@@ -705,8 +705,8 @@ svc_rqst_alloc(struct svc_serv *serv, struct svc_pool *pool, int node)
 	rqstp->rq_server = serv;
 	rqstp->rq_pool = pool;
 
-	rqstp->rq_scratch_page = alloc_pages_node(node, GFP_KERNEL, 0);
-	if (!rqstp->rq_scratch_page)
+	rqstp->rq_scratch_folio = __folio_alloc_node(GFP_KERNEL, 0, node);
+	if (!rqstp->rq_scratch_folio)
 		goto out_enomem;
 
 	rqstp->rq_argp = kmalloc_node(serv->sv_xdrsize, GFP_KERNEL, node);
-- 
2.53.0

[PATCH 6.6.y 7/7] sunrpc: defer rq_argp and rq_resp free until after RCU grace period

[Sasha Levin]

From: Jeff Layton <jlayton@kernel.org>

[ Upstream commit c479bde671cbe2f9e152834a8b0eb7c3c295bbaf ]

svc_rqst_free() frees rqstp->rq_argp and rqstp->rq_resp synchronously
via kfree(), but defers the rqstp struct free via kfree_rcu().  After
svc_exit_thread() calls list_del_rcu() and svc_rqst_free(), there is
a window where RCU readers that started before list_del_rcu() can still
traverse the thread list and find the rqstp.  These readers (e.g.
nfsd_nl_rpc_status_get_dumpit()) dereference rqstp->rq_argp, which has
already been freed — a use-after-free.

Fix this by moving the kfree of rq_argp and rq_resp into an explicit
call_rcu() callback alongside the struct free.  Resources not accessed
by RCU readers (bvec, buffer pages, scratch folio, auth_data) remain
synchronously freed.

Fixes: 812443865c5f ("sunrpc: add a rcu_head to svc_rqst and use kfree_rcu to free it")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260611-nfsd-testing-v2-4-5b90e276f2d9@kernel.org
Signed-off-by: Chuck Lever <cel@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/sunrpc/svc.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index bfd685dfc70e9..b6c4287077fbd 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -677,6 +677,15 @@ svc_release_buffer(struct svc_rqst *rqstp)
 			put_page(rqstp->rq_pages[i]);
 }
 
+static void svc_rqst_free_rcu(struct rcu_head *head)
+{
+	struct svc_rqst *rqstp = container_of(head, struct svc_rqst, rq_rcu_head);
+
+	kfree(rqstp->rq_resp);
+	kfree(rqstp->rq_argp);
+	kfree(rqstp);
+}
+
 static void
 svc_rqst_free(struct svc_rqst *rqstp)
 {
@@ -684,10 +693,8 @@ svc_rqst_free(struct svc_rqst *rqstp)
 	svc_release_buffer(rqstp);
 	if (rqstp->rq_scratch_folio)
 		folio_put(rqstp->rq_scratch_folio);
-	kfree(rqstp->rq_resp);
-	kfree(rqstp->rq_argp);
 	kfree(rqstp->rq_auth_data);
-	kfree_rcu(rqstp, rq_rcu_head);
+	call_rcu(&rqstp->rq_rcu_head, svc_rqst_free_rcu);
 }
 
 static struct svc_rqst *
-- 
2.53.0

[PATCH 6.6.y 1/4] SUNRPC: move all of xprt handling into svc_xprt_handle()

[Sasha Levin]

From: NeilBrown <neilb@suse.de>

[ Upstream commit e3274026e2ec69eec6ab51bc499e14bb548548d0 ]

svc_xprt_handle() does lots of things itself, but leaves some to the
caller - svc_recv().  This isn't elegant.

Move that code out of svc_recv() into svc_xprt_handle()

Move the calls to svc_xprt_release() from svc_send() and svc_drop()
(the two possible final steps in svc_process()) and from svc_recv() (in
the case where svc_process() wasn't called) into svc_xprt_handle().

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Stable-dep-of: c479bde671cb ("sunrpc: defer rq_argp and rq_resp free until after RCU grace period")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/sunrpc/svc_xprt.c | 53 ++++++++++++++++---------------------------
 1 file changed, 20 insertions(+), 33 deletions(-)

diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 5cfe5c7408b74..5440d6b50efa5 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -784,7 +784,7 @@ static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt
 	svc_xprt_received(newxpt);
 }
 
-static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
+static void svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 {
 	struct svc_serv *serv = rqstp->rq_server;
 	int len = 0;
@@ -825,11 +825,26 @@ static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 			len = xprt->xpt_ops->xpo_recvfrom(rqstp);
 		rqstp->rq_reserved = serv->sv_max_mesg;
 		atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
+		if (len <= 0)
+			goto out;
+
+		trace_svc_xdr_recvfrom(&rqstp->rq_arg);
+
+		clear_bit(XPT_OLD, &xprt->xpt_flags);
+
+		rqstp->rq_chandle.defer = svc_defer;
+
+		if (serv->sv_stats)
+			serv->sv_stats->netcnt++;
+		percpu_counter_inc(&rqstp->rq_pool->sp_messages_arrived);
+		rqstp->rq_stime = ktime_get();
+		svc_process(rqstp);
 	} else
 		svc_xprt_received(xprt);
 
 out:
-	return len;
+	rqstp->rq_res.len = 0;
+	svc_xprt_release(rqstp);
 }
 
 /**
@@ -843,11 +858,9 @@ static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 void svc_recv(struct svc_rqst *rqstp)
 {
 	struct svc_xprt		*xprt = NULL;
-	struct svc_serv		*serv = rqstp->rq_server;
-	int			len;
 
 	if (!svc_alloc_arg(rqstp))
-		goto out;
+		return;
 
 	try_to_freeze();
 	cond_resched();
@@ -855,31 +868,9 @@ void svc_recv(struct svc_rqst *rqstp)
 		goto out;
 
 	xprt = svc_get_next_xprt(rqstp);
-	if (!xprt)
-		goto out;
-
-	len = svc_handle_xprt(rqstp, xprt);
-
-	/* No data, incomplete (TCP) read, or accept() */
-	if (len <= 0)
-		goto out_release;
-
-	trace_svc_xdr_recvfrom(&rqstp->rq_arg);
-
-	clear_bit(XPT_OLD, &xprt->xpt_flags);
-
-	rqstp->rq_chandle.defer = svc_defer;
-
-	if (serv->sv_stats)
-		serv->sv_stats->netcnt++;
-	percpu_counter_inc(&rqstp->rq_pool->sp_messages_arrived);
-	rqstp->rq_stime = ktime_get();
-	svc_process(rqstp);
+	if (xprt)
+		svc_handle_xprt(rqstp, xprt);
 out:
-	return;
-out_release:
-	rqstp->rq_res.len = 0;
-	svc_xprt_release(rqstp);
 }
 EXPORT_SYMBOL_GPL(svc_recv);
 
@@ -889,7 +880,6 @@ EXPORT_SYMBOL_GPL(svc_recv);
 void svc_drop(struct svc_rqst *rqstp)
 {
 	trace_svc_drop(rqstp);
-	svc_xprt_release(rqstp);
 }
 EXPORT_SYMBOL_GPL(svc_drop);
 
@@ -905,8 +895,6 @@ void svc_send(struct svc_rqst *rqstp)
 	int status;
 
 	xprt = rqstp->rq_xprt;
-	if (!xprt)
-		return;
 
 	/* calculate over-all length */
 	xb = &rqstp->rq_res;
@@ -919,7 +907,6 @@ void svc_send(struct svc_rqst *rqstp)
 	status = xprt->xpt_ops->xpo_sendto(rqstp);
 
 	trace_svc_send(rqstp, status);
-	svc_xprt_release(rqstp);
 }
 
 /*
-- 
2.53.0

[PATCH 6.6.y 2/4] SUNRPC: Add a server-side API for retrieving an RPC's pseudoflavor

[Sasha Levin]

From: Chuck Lever <chuck.lever@oracle.com>

[ Upstream commit deb704281f076097b0347116a82edeba96697db1 ]

NFSD will use this new API to determine whether nfsd_splice_read is
safe to use. This avoids the need to add a dependency to NFSD for
CONFIG_SUNRPC_GSS.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Stable-dep-of: c479bde671cb ("sunrpc: defer rq_argp and rq_resp free until after RCU grace period")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/sunrpc/svcauth.h    |  7 ++++++-
 net/sunrpc/auth_gss/svcauth_gss.c |  6 ++++++
 net/sunrpc/svcauth.c              | 16 ++++++++++++++++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/include/linux/sunrpc/svcauth.h b/include/linux/sunrpc/svcauth.h
index 6f90203edbf8d..61c455f1e1f50 100644
--- a/include/linux/sunrpc/svcauth.h
+++ b/include/linux/sunrpc/svcauth.h
@@ -131,8 +131,11 @@ enum svc_auth_status {
  *   This call releases a domain.
  *
  * set_client()
- *   Givens a pending request (struct svc_rqst), finds and assigns
+ *   Given a pending request (struct svc_rqst), finds and assigns
  *   an appropriate 'auth_domain' as the client.
+ *
+ * pseudoflavor()
+ *   Returns RPC_AUTH pseudoflavor in use by @rqstp.
  */
 struct auth_ops {
 	char *	name;
@@ -143,11 +146,13 @@ struct auth_ops {
 	int			(*release)(struct svc_rqst *rqstp);
 	void			(*domain_release)(struct auth_domain *dom);
 	enum svc_auth_status	(*set_client)(struct svc_rqst *rqstp);
+	rpc_authflavor_t	(*pseudoflavor)(struct svc_rqst *rqstp);
 };
 
 struct svc_xprt;
 
 extern enum svc_auth_status svc_authenticate(struct svc_rqst *rqstp);
+extern rpc_authflavor_t svc_auth_flavor(struct svc_rqst *rqstp);
 extern int	svc_authorise(struct svc_rqst *rqstp);
 extern enum svc_auth_status svc_set_client(struct svc_rqst *rqstp);
 extern int	svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops);
diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 49a8623cc1d57..3015839da877f 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -2009,6 +2009,11 @@ svcauth_gss_domain_release(struct auth_domain *dom)
 	call_rcu(&dom->rcu_head, svcauth_gss_domain_release_rcu);
 }
 
+static rpc_authflavor_t svcauth_gss_pseudoflavor(struct svc_rqst *rqstp)
+{
+	return svcauth_gss_flavor(rqstp->rq_gssclient);
+}
+
 static struct auth_ops svcauthops_gss = {
 	.name		= "rpcsec_gss",
 	.owner		= THIS_MODULE,
@@ -2017,6 +2022,7 @@ static struct auth_ops svcauthops_gss = {
 	.release	= svcauth_gss_release,
 	.domain_release = svcauth_gss_domain_release,
 	.set_client	= svcauth_gss_set_client,
+	.pseudoflavor	= svcauth_gss_pseudoflavor,
 };
 
 static int rsi_cache_create_net(struct net *net)
diff --git a/net/sunrpc/svcauth.c b/net/sunrpc/svcauth.c
index aa4429d0b8106..1619211f0960a 100644
--- a/net/sunrpc/svcauth.c
+++ b/net/sunrpc/svcauth.c
@@ -160,6 +160,22 @@ svc_auth_unregister(rpc_authflavor_t flavor)
 }
 EXPORT_SYMBOL_GPL(svc_auth_unregister);
 
+/**
+ * svc_auth_flavor - return RPC transaction's RPC_AUTH flavor
+ * @rqstp: RPC transaction context
+ *
+ * Returns an RPC flavor or GSS pseudoflavor.
+ */
+rpc_authflavor_t svc_auth_flavor(struct svc_rqst *rqstp)
+{
+	struct auth_ops *aops = rqstp->rq_authop;
+
+	if (!aops->pseudoflavor)
+		return aops->flavour;
+	return aops->pseudoflavor(rqstp);
+}
+EXPORT_SYMBOL_GPL(svc_auth_flavor);
+
 /**************************************************
  * 'auth_domains' are stored in a hash table indexed by name.
  * When the last reference to an 'auth_domain' is dropped,
-- 
2.53.0

[PATCH 6.6.y 3/4] sunrpc: refactor pool_mode setting code

[Sasha Levin]

From: Jeff Layton <jlayton@kernel.org>

[ Upstream commit 5f71f3c325534da55dfda487a67208e2e0f0cd1b ]

Allow the pool_mode setting code to be called from internal callers
so we can call it from a new netlink op. Add a new svc_pool_map_get
function to return the current setting. Change the existing module
parameter handling to use the new interfaces under the hood.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Stable-dep-of: c479bde671cb ("sunrpc: defer rq_argp and rq_resp free until after RCU grace period")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/sunrpc/svc.h |  2 +
 net/sunrpc/svc.c           | 85 ++++++++++++++++++++++++++++----------
 2 files changed, 66 insertions(+), 21 deletions(-)

diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 3d8b215f32d5b..d4558fefd9b4e 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -395,6 +395,8 @@ struct svc_procedure {
 /*
  * Function prototypes.
  */
+int sunrpc_set_pool_mode(const char *val);
+int sunrpc_get_pool_mode(char *val, size_t size);
 int svc_rpcb_setup(struct svc_serv *serv, struct net *net);
 void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net);
 int svc_bind(struct svc_serv *serv, struct net *net);
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 4d8d460747164..bf88a955920f2 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -72,57 +72,100 @@ static struct svc_pool_map svc_pool_map = {
 static DEFINE_MUTEX(svc_pool_map_mutex);/* protects svc_pool_map.count only */
 
 static int
-param_set_pool_mode(const char *val, const struct kernel_param *kp)
+__param_set_pool_mode(const char *val, struct svc_pool_map *m)
 {
-	int *ip = (int *)kp->arg;
-	struct svc_pool_map *m = &svc_pool_map;
-	int err;
+	int err, mode;
 
 	mutex_lock(&svc_pool_map_mutex);
 
-	err = -EBUSY;
-	if (m->count)
-		goto out;
-
 	err = 0;
 	if (!strncmp(val, "auto", 4))
-		*ip = SVC_POOL_AUTO;
+		mode = SVC_POOL_AUTO;
 	else if (!strncmp(val, "global", 6))
-		*ip = SVC_POOL_GLOBAL;
+		mode = SVC_POOL_GLOBAL;
 	else if (!strncmp(val, "percpu", 6))
-		*ip = SVC_POOL_PERCPU;
+		mode = SVC_POOL_PERCPU;
 	else if (!strncmp(val, "pernode", 7))
-		*ip = SVC_POOL_PERNODE;
+		mode = SVC_POOL_PERNODE;
 	else
 		err = -EINVAL;
 
+	if (err)
+		goto out;
+
+	if (m->count == 0)
+		m->mode = mode;
+	else if (mode != m->mode)
+		err = -EBUSY;
 out:
 	mutex_unlock(&svc_pool_map_mutex);
 	return err;
 }
 
 static int
-param_get_pool_mode(char *buf, const struct kernel_param *kp)
+param_set_pool_mode(const char *val, const struct kernel_param *kp)
+{
+	struct svc_pool_map *m = kp->arg;
+
+	return __param_set_pool_mode(val, m);
+}
+
+int sunrpc_set_pool_mode(const char *val)
+{
+	return __param_set_pool_mode(val, &svc_pool_map);
+}
+EXPORT_SYMBOL(sunrpc_set_pool_mode);
+
+/**
+ * sunrpc_get_pool_mode - get the current pool_mode for the host
+ * @buf: where to write the current pool_mode
+ * @size: size of @buf
+ *
+ * Grab the current pool_mode from the svc_pool_map and write
+ * the resulting string to @buf. Returns the number of characters
+ * written to @buf (a'la snprintf()).
+ */
+int
+sunrpc_get_pool_mode(char *buf, size_t size)
 {
-	int *ip = (int *)kp->arg;
+	struct svc_pool_map *m = &svc_pool_map;
 
-	switch (*ip)
+	switch (m->mode)
 	{
 	case SVC_POOL_AUTO:
-		return sysfs_emit(buf, "auto\n");
+		return snprintf(buf, size, "auto");
 	case SVC_POOL_GLOBAL:
-		return sysfs_emit(buf, "global\n");
+		return snprintf(buf, size, "global");
 	case SVC_POOL_PERCPU:
-		return sysfs_emit(buf, "percpu\n");
+		return snprintf(buf, size, "percpu");
 	case SVC_POOL_PERNODE:
-		return sysfs_emit(buf, "pernode\n");
+		return snprintf(buf, size, "pernode");
 	default:
-		return sysfs_emit(buf, "%d\n", *ip);
+		return snprintf(buf, size, "%d", m->mode);
 	}
 }
+EXPORT_SYMBOL(sunrpc_get_pool_mode);
+
+static int
+param_get_pool_mode(char *buf, const struct kernel_param *kp)
+{
+	char str[16];
+	int len;
+
+	len = sunrpc_get_pool_mode(str, ARRAY_SIZE(str));
+
+	/* Ensure we have room for newline and NUL */
+	len = min_t(int, len, ARRAY_SIZE(str) - 2);
+
+	/* tack on the newline */
+	str[len] = '\n';
+	str[len + 1] = '\0';
+
+	return sysfs_emit(buf, str);
+}
 
 module_param_call(pool_mode, param_set_pool_mode, param_get_pool_mode,
-		 &svc_pool_map.mode, 0644);
+		  &svc_pool_map, 0644);
 
 /*
  * Detect best pool mapping mode heuristically,
-- 
2.53.0

[PATCH 6.6.y 4/4] sunrpc: defer rq_argp and rq_resp free until after RCU grace period

[Sasha Levin]

From: Jeff Layton <jlayton@kernel.org>

[ Upstream commit c479bde671cbe2f9e152834a8b0eb7c3c295bbaf ]

svc_rqst_free() frees rqstp->rq_argp and rqstp->rq_resp synchronously
via kfree(), but defers the rqstp struct free via kfree_rcu().  After
svc_exit_thread() calls list_del_rcu() and svc_rqst_free(), there is
a window where RCU readers that started before list_del_rcu() can still
traverse the thread list and find the rqstp.  These readers (e.g.
nfsd_nl_rpc_status_get_dumpit()) dereference rqstp->rq_argp, which has
already been freed — a use-after-free.

Fix this by moving the kfree of rq_argp and rq_resp into an explicit
call_rcu() callback alongside the struct free.  Resources not accessed
by RCU readers (bvec, buffer pages, scratch folio, auth_data) remain
synchronously freed.

Fixes: 812443865c5f ("sunrpc: add a rcu_head to svc_rqst and use kfree_rcu to free it")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260611-nfsd-testing-v2-4-5b90e276f2d9@kernel.org
Signed-off-by: Chuck Lever <cel@kernel.org>
[ placed the RCU callback beside the older exported svc_rqst_free() while retaining page-based synchronous cleanup. ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/sunrpc/svc.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index bf88a955920f2..ca0a854c9fdcf 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -946,6 +946,15 @@ void svc_rqst_release_pages(struct svc_rqst *rqstp)
 	}
 }
 
+static void svc_rqst_free_rcu(struct rcu_head *head)
+{
+	struct svc_rqst *rqstp = container_of(head, struct svc_rqst, rq_rcu_head);
+
+	kfree(rqstp->rq_resp);
+	kfree(rqstp->rq_argp);
+	kfree(rqstp);
+}
+
 /*
  * Called from a server thread as it's exiting. Caller must hold the "service
  * mutex" for the service.
@@ -957,10 +966,8 @@ svc_rqst_free(struct svc_rqst *rqstp)
 	svc_release_buffer(rqstp);
 	if (rqstp->rq_scratch_page)
 		put_page(rqstp->rq_scratch_page);
-	kfree(rqstp->rq_resp);
-	kfree(rqstp->rq_argp);
 	kfree(rqstp->rq_auth_data);
-	kfree_rcu(rqstp, rq_rcu_head);
+	call_rcu(&rqstp->rq_rcu_head, svc_rqst_free_rcu);
 }
 EXPORT_SYMBOL_GPL(svc_rqst_free);
 
-- 
2.53.0