Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEADgrafted

Changes:

Make expedited grace periods expedite normal RCU callbacks

Miscellaneous fixes:
 * Improve diagnostic output with character task states.
 * Mark accesses to inform KCSAN of concurrency design.
 * Move from kmalloc() to kmalloc_obj().
 * Documentation updates.
 * Improve handling of RCU deferred quiescent states.
 * Clean up unused function arguments and structure fields.
 * Reduce show_rcu_gp_kthreads() stack space.

Tasks RCU updates:
 * Clean up after SRCU re-implementation of Tasks Trace RCU.
 * Mark accesses to inform KCSAN of concurrency design.
 * Add ->lazy_timer status to diagnostic output.
 * Remove an unnecessary memory barrier.
 * Fix a data race, courtesy of KCSAN.
 * Documentation updates.
 * Convert cond_resched_tasks_rcu_qs() from macro to static inline
   function.

SRCU updates:
 * Add Rust helpers for SRCU.
 * Avoid losing queued work at cleanup_srcu_struct() time.

Torture-test updates:
 * Preparation work for immediate RCU priority deboosting.
 * Test RCU readers from real interrupt handlers (as opposed to softirq).
 * Simplify code through use of cpumask_next_wrap().
 * Improve diagnostic output with character task states.
 * Add rcutorture.nwriters parameter to allow lightweight stall testing,
   and rcutorture.stall_only to make doing so easier.
 * Test an RCU Tasks Trace grace period implying an RCU grace period.
 * Make RCU Tasks Trace torturing track reader batches.
 * Fix a data race, courtesy of KCSAN.
 * Plug a shuffle_tmp_mask memory leak on kthread spawn failure.

1 files changed, 271 insertions, 0 deletions

diff --git a/net/ethtool/plca.c b/net/ethtool/plca.c
new file mode 100644
index 000000000..91f0c4233
--- /dev/null
+++ b/net/ethtool/plca.c
@@ -0,0 +1,271 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/phy.h>
+#include <linux/ethtool_netlink.h>
+
+#include "common.h"
+#include "netlink.h"
+
+struct plca_req_info {
+	struct ethnl_req_info		base;
+};
+
+struct plca_reply_data {
+	struct ethnl_reply_data		base;
+	struct phy_plca_cfg		plca_cfg;
+	struct phy_plca_status		plca_st;
+};
+
+// Helpers ------------------------------------------------------------------ //
+
+#define PLCA_REPDATA(__reply_base) \
+	container_of(__reply_base, struct plca_reply_data, base)
+
+// PLCA get configuration message ------------------------------------------- //
+
+const struct nla_policy ethnl_plca_get_cfg_policy[] = {
+	[ETHTOOL_A_PLCA_HEADER]		=
+		NLA_POLICY_NESTED(ethnl_header_policy_phy),
+};
+
+static void plca_update_sint(int *dst, struct nlattr **tb, u32 attrid,
+			     bool *mod)
+{
+	const struct nlattr *attr = tb[attrid];
+
+	if (!attr ||
+	    WARN_ON_ONCE(attrid >= ARRAY_SIZE(ethnl_plca_set_cfg_policy)))
+		return;
+
+	switch (ethnl_plca_set_cfg_policy[attrid].type) {
+	case NLA_U8:
+		*dst = nla_get_u8(attr);
+		break;
+	case NLA_U32:
+		*dst = nla_get_u32(attr);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+	}
+
+	*mod = true;
+}
+
+static int plca_get_cfg_prepare_data(const struct ethnl_req_info *req_base,
+				     struct ethnl_reply_data *reply_base,
+				     const struct genl_info *info)
+{
+	struct plca_reply_data *data = PLCA_REPDATA(reply_base);
+	struct net_device *dev = reply_base->dev;
+	const struct ethtool_phy_ops *ops;
+	struct nlattr **tb = info->attrs;
+	struct phy_device *phydev;
+	int ret;
+
+	phydev = ethnl_req_get_phydev(req_base, tb, ETHTOOL_A_PLCA_HEADER,
+				      info->extack);
+	// check that the PHY device is available and connected
+	if (IS_ERR_OR_NULL(phydev)) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
+	// note: rtnl_lock is held already by ethnl_default_doit
+	ops = ethtool_phy_ops;
+	if (!ops || !ops->get_plca_cfg) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
+	ret = ethnl_ops_begin(dev);
+	if (ret < 0)
+		goto out;
+
+	memset(&data->plca_cfg, 0xff,
+	       sizeof_field(struct plca_reply_data, plca_cfg));
+
+	ret = ops->get_plca_cfg(phydev, &data->plca_cfg);
+	ethnl_ops_complete(dev);
+
+out:
+	return ret;
+}
+
+static int plca_get_cfg_reply_size(const struct ethnl_req_info *req_base,
+				   const struct ethnl_reply_data *reply_base)
+{
+	return nla_total_size(sizeof(u16)) +	/* _VERSION */
+	       nla_total_size(sizeof(u8)) +	/* _ENABLED */
+	       nla_total_size(sizeof(u32)) +	/* _NODE_CNT */
+	       nla_total_size(sizeof(u32)) +	/* _NODE_ID */
+	       nla_total_size(sizeof(u32)) +	/* _TO_TIMER */
+	       nla_total_size(sizeof(u32)) +	/* _BURST_COUNT */
+	       nla_total_size(sizeof(u32));	/* _BURST_TIMER */
+}
+
+static int plca_get_cfg_fill_reply(struct sk_buff *skb,
+				   const struct ethnl_req_info *req_base,
+				   const struct ethnl_reply_data *reply_base)
+{
+	const struct plca_reply_data *data = PLCA_REPDATA(reply_base);
+	const struct phy_plca_cfg *plca = &data->plca_cfg;
+
+	if ((plca->version >= 0 &&
+	     nla_put_u16(skb, ETHTOOL_A_PLCA_VERSION, plca->version)) ||
+	    (plca->enabled >= 0 &&
+	     nla_put_u8(skb, ETHTOOL_A_PLCA_ENABLED, !!plca->enabled)) ||
+	    (plca->node_id >= 0 &&
+	     nla_put_u32(skb, ETHTOOL_A_PLCA_NODE_ID, plca->node_id)) ||
+	    (plca->node_cnt >= 0 &&
+	     nla_put_u32(skb, ETHTOOL_A_PLCA_NODE_CNT, plca->node_cnt)) ||
+	    (plca->to_tmr >= 0 &&
+	     nla_put_u32(skb, ETHTOOL_A_PLCA_TO_TMR, plca->to_tmr)) ||
+	    (plca->burst_cnt >= 0 &&
+	     nla_put_u32(skb, ETHTOOL_A_PLCA_BURST_CNT, plca->burst_cnt)) ||
+	    (plca->burst_tmr >= 0 &&
+	     nla_put_u32(skb, ETHTOOL_A_PLCA_BURST_TMR, plca->burst_tmr)))
+		return -EMSGSIZE;
+
+	return 0;
+};
+
+// PLCA set configuration message ------------------------------------------- //
+
+const struct nla_policy ethnl_plca_set_cfg_policy[] = {
+	[ETHTOOL_A_PLCA_HEADER]		=
+		NLA_POLICY_NESTED(ethnl_header_policy_phy),
+	[ETHTOOL_A_PLCA_ENABLED]	= NLA_POLICY_MAX(NLA_U8, 1),
+	[ETHTOOL_A_PLCA_NODE_ID]	= NLA_POLICY_MAX(NLA_U32, 255),
+	[ETHTOOL_A_PLCA_NODE_CNT]	= NLA_POLICY_RANGE(NLA_U32, 1, 255),
+	[ETHTOOL_A_PLCA_TO_TMR]		= NLA_POLICY_MAX(NLA_U32, 255),
+	[ETHTOOL_A_PLCA_BURST_CNT]	= NLA_POLICY_MAX(NLA_U32, 255),
+	[ETHTOOL_A_PLCA_BURST_TMR]	= NLA_POLICY_MAX(NLA_U32, 255),
+};
+
+static int
+ethnl_set_plca(struct ethnl_req_info *req_info, struct genl_info *info)
+{
+	const struct ethtool_phy_ops *ops;
+	struct nlattr **tb = info->attrs;
+	struct phy_plca_cfg plca_cfg;
+	struct phy_device *phydev;
+	bool mod = false;
+	int ret;
+
+	phydev = ethnl_req_get_phydev(req_info, tb, ETHTOOL_A_PLCA_HEADER,
+				      info->extack);
+	// check that the PHY device is available and connected
+	if (IS_ERR_OR_NULL(phydev))
+		return -EOPNOTSUPP;
+
+	ops = ethtool_phy_ops;
+	if (!ops || !ops->set_plca_cfg)
+		return -EOPNOTSUPP;
+
+	memset(&plca_cfg, 0xff, sizeof(plca_cfg));
+	plca_update_sint(&plca_cfg.enabled, tb, ETHTOOL_A_PLCA_ENABLED, &mod);
+	plca_update_sint(&plca_cfg.node_id, tb, ETHTOOL_A_PLCA_NODE_ID, &mod);
+	plca_update_sint(&plca_cfg.node_cnt, tb, ETHTOOL_A_PLCA_NODE_CNT, &mod);
+	plca_update_sint(&plca_cfg.to_tmr, tb, ETHTOOL_A_PLCA_TO_TMR, &mod);
+	plca_update_sint(&plca_cfg.burst_cnt, tb, ETHTOOL_A_PLCA_BURST_CNT,
+			 &mod);
+	plca_update_sint(&plca_cfg.burst_tmr, tb, ETHTOOL_A_PLCA_BURST_TMR,
+			 &mod);
+	if (!mod)
+		return 0;
+
+	ret = ops->set_plca_cfg(phydev, &plca_cfg, info->extack);
+	return ret < 0 ? ret : 1;
+}
+
+const struct ethnl_request_ops ethnl_plca_cfg_request_ops = {
+	.request_cmd		= ETHTOOL_MSG_PLCA_GET_CFG,
+	.reply_cmd		= ETHTOOL_MSG_PLCA_GET_CFG_REPLY,
+	.hdr_attr		= ETHTOOL_A_PLCA_HEADER,
+	.req_info_size		= sizeof(struct plca_req_info),
+	.reply_data_size	= sizeof(struct plca_reply_data),
+
+	.prepare_data		= plca_get_cfg_prepare_data,
+	.reply_size		= plca_get_cfg_reply_size,
+	.fill_reply		= plca_get_cfg_fill_reply,
+
+	.set			= ethnl_set_plca,
+	.set_ntf_cmd		= ETHTOOL_MSG_PLCA_NTF,
+};
+
+// PLCA get status message -------------------------------------------------- //
+
+const struct nla_policy ethnl_plca_get_status_policy[] = {
+	[ETHTOOL_A_PLCA_HEADER]		=
+		NLA_POLICY_NESTED(ethnl_header_policy_phy),
+};
+
+static int plca_get_status_prepare_data(const struct ethnl_req_info *req_base,
+					struct ethnl_reply_data *reply_base,
+					const struct genl_info *info)
+{
+	struct plca_reply_data *data = PLCA_REPDATA(reply_base);
+	struct net_device *dev = reply_base->dev;
+	const struct ethtool_phy_ops *ops;
+	struct nlattr **tb = info->attrs;
+	struct phy_device *phydev;
+	int ret;
+
+	phydev = ethnl_req_get_phydev(req_base, tb, ETHTOOL_A_PLCA_HEADER,
+				      info->extack);
+	// check that the PHY device is available and connected
+	if (IS_ERR_OR_NULL(phydev)) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
+	// note: rtnl_lock is held already by ethnl_default_doit
+	ops = ethtool_phy_ops;
+	if (!ops || !ops->get_plca_status) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
+	ret = ethnl_ops_begin(dev);
+	if (ret < 0)
+		goto out;
+
+	memset(&data->plca_st, 0xff,
+	       sizeof_field(struct plca_reply_data, plca_st));
+
+	ret = ops->get_plca_status(phydev, &data->plca_st);
+	ethnl_ops_complete(dev);
+out:
+	return ret;
+}
+
+static int plca_get_status_reply_size(const struct ethnl_req_info *req_base,
+				      const struct ethnl_reply_data *reply_base)
+{
+	return nla_total_size(sizeof(u8));	/* _STATUS */
+}
+
+static int plca_get_status_fill_reply(struct sk_buff *skb,
+				      const struct ethnl_req_info *req_base,
+				      const struct ethnl_reply_data *reply_base)
+{
+	const struct plca_reply_data *data = PLCA_REPDATA(reply_base);
+	const u8 status = data->plca_st.pst;
+
+	if (nla_put_u8(skb, ETHTOOL_A_PLCA_STATUS, !!status))
+		return -EMSGSIZE;
+
+	return 0;
+};
+
+const struct ethnl_request_ops ethnl_plca_status_request_ops = {
+	.request_cmd		= ETHTOOL_MSG_PLCA_GET_STATUS,
+	.reply_cmd		= ETHTOOL_MSG_PLCA_GET_STATUS_REPLY,
+	.hdr_attr		= ETHTOOL_A_PLCA_HEADER,
+	.req_info_size		= sizeof(struct plca_req_info),
+	.reply_data_size	= sizeof(struct plca_reply_data),
+
+	.prepare_data		= plca_get_status_prepare_data,
+	.reply_size		= plca_get_status_reply_size,
+	.fill_reply		= plca_get_status_fill_reply,
+};