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, 226 insertions, 0 deletions

diff --git a/net/ethtool/linkstate.c b/net/ethtool/linkstate.c
new file mode 100644
index 000000000..24569e929
--- /dev/null
+++ b/net/ethtool/linkstate.c
@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/phy.h>
+#include <linux/phylib_stubs.h>
+
+#include "common.h"
+#include "netlink.h"
+
+struct linkstate_req_info {
+	struct ethnl_req_info		base;
+};
+
+struct linkstate_reply_data {
+	struct ethnl_reply_data			base;
+	int					link;
+	int					sqi;
+	int					sqi_max;
+	struct ethtool_link_ext_stats		link_stats;
+	bool					link_ext_state_provided;
+	struct ethtool_link_ext_state_info	ethtool_link_ext_state_info;
+};
+
+#define LINKSTATE_REPDATA(__reply_base) \
+	container_of(__reply_base, struct linkstate_reply_data, base)
+
+const struct nla_policy ethnl_linkstate_get_policy[] = {
+	[ETHTOOL_A_LINKSTATE_HEADER]		=
+		NLA_POLICY_NESTED(ethnl_header_policy_stats),
+};
+
+static int linkstate_get_sqi(struct phy_device *phydev)
+{
+	int ret;
+
+	if (!phydev)
+		return -EOPNOTSUPP;
+
+	mutex_lock(&phydev->lock);
+	if (!phydev->drv || !phydev->drv->get_sqi)
+		ret = -EOPNOTSUPP;
+	else if (!phydev->link)
+		ret = -ENETDOWN;
+	else
+		ret = phydev->drv->get_sqi(phydev);
+	mutex_unlock(&phydev->lock);
+
+	return ret;
+}
+
+static int linkstate_get_sqi_max(struct phy_device *phydev)
+{
+	int ret;
+
+	if (!phydev)
+		return -EOPNOTSUPP;
+
+	mutex_lock(&phydev->lock);
+	if (!phydev->drv || !phydev->drv->get_sqi_max)
+		ret = -EOPNOTSUPP;
+	else if (!phydev->link)
+		ret = -ENETDOWN;
+	else
+		ret = phydev->drv->get_sqi_max(phydev);
+	mutex_unlock(&phydev->lock);
+
+	return ret;
+};
+
+static bool linkstate_sqi_critical_error(int sqi)
+{
+	return sqi < 0 && sqi != -EOPNOTSUPP && sqi != -ENETDOWN;
+}
+
+static bool linkstate_sqi_valid(struct linkstate_reply_data *data)
+{
+	return data->sqi >= 0 && data->sqi_max >= 0 &&
+	       data->sqi <= data->sqi_max;
+}
+
+static int linkstate_get_link_ext_state(struct net_device *dev,
+					struct linkstate_reply_data *data)
+{
+	int err;
+
+	if (!dev->ethtool_ops->get_link_ext_state)
+		return -EOPNOTSUPP;
+
+	err = dev->ethtool_ops->get_link_ext_state(dev, &data->ethtool_link_ext_state_info);
+	if (err)
+		return err;
+
+	data->link_ext_state_provided = true;
+
+	return 0;
+}
+
+static int linkstate_prepare_data(const struct ethnl_req_info *req_base,
+				  struct ethnl_reply_data *reply_base,
+				  const struct genl_info *info)
+{
+	struct linkstate_reply_data *data = LINKSTATE_REPDATA(reply_base);
+	struct net_device *dev = reply_base->dev;
+	struct nlattr **tb = info->attrs;
+	struct phy_device *phydev;
+	int ret;
+
+	phydev = ethnl_req_get_phydev(req_base, tb, ETHTOOL_A_LINKSTATE_HEADER,
+				      info->extack);
+	if (IS_ERR(phydev))
+		return PTR_ERR(phydev);
+
+	ret = ethnl_ops_begin(dev);
+	if (ret < 0)
+		return ret;
+	data->link = __ethtool_get_link(dev);
+
+	ret = linkstate_get_sqi(phydev);
+	if (linkstate_sqi_critical_error(ret))
+		goto out;
+	data->sqi = ret;
+
+	ret = linkstate_get_sqi_max(phydev);
+	if (linkstate_sqi_critical_error(ret))
+		goto out;
+	data->sqi_max = ret;
+
+	if (dev->flags & IFF_UP) {
+		ret = linkstate_get_link_ext_state(dev, data);
+		if (ret < 0 && ret != -EOPNOTSUPP && ret != -ENODATA)
+			goto out;
+	}
+
+	ethtool_stats_init((u64 *)&data->link_stats,
+			   sizeof(data->link_stats) / 8);
+
+	if (req_base->flags & ETHTOOL_FLAG_STATS) {
+		if (phydev)
+			phy_ethtool_get_link_ext_stats(phydev,
+						       &data->link_stats);
+
+		if (dev->ethtool_ops->get_link_ext_stats)
+			dev->ethtool_ops->get_link_ext_stats(dev,
+							     &data->link_stats);
+	}
+
+	ret = 0;
+out:
+	ethnl_ops_complete(dev);
+	return ret;
+}
+
+static int linkstate_reply_size(const struct ethnl_req_info *req_base,
+				const struct ethnl_reply_data *reply_base)
+{
+	struct linkstate_reply_data *data = LINKSTATE_REPDATA(reply_base);
+	int len;
+
+	len = nla_total_size(sizeof(u8)) /* LINKSTATE_LINK */
+		+ 0;
+
+	if (linkstate_sqi_valid(data)) {
+		len += nla_total_size(sizeof(u32)); /* LINKSTATE_SQI */
+		len += nla_total_size(sizeof(u32)); /* LINKSTATE_SQI_MAX */
+	}
+
+	if (data->link_ext_state_provided)
+		len += nla_total_size(sizeof(u8)); /* LINKSTATE_EXT_STATE */
+
+	if (data->ethtool_link_ext_state_info.__link_ext_substate)
+		len += nla_total_size(sizeof(u8)); /* LINKSTATE_EXT_SUBSTATE */
+
+	if (data->link_stats.link_down_events != ETHTOOL_STAT_NOT_SET)
+		len += nla_total_size(sizeof(u32));
+
+	return len;
+}
+
+static int linkstate_fill_reply(struct sk_buff *skb,
+				const struct ethnl_req_info *req_base,
+				const struct ethnl_reply_data *reply_base)
+{
+	struct linkstate_reply_data *data = LINKSTATE_REPDATA(reply_base);
+
+	if (data->link >= 0 &&
+	    nla_put_u8(skb, ETHTOOL_A_LINKSTATE_LINK, !!data->link))
+		return -EMSGSIZE;
+
+	if (linkstate_sqi_valid(data)) {
+		if (nla_put_u32(skb, ETHTOOL_A_LINKSTATE_SQI, data->sqi))
+			return -EMSGSIZE;
+
+		if (nla_put_u32(skb, ETHTOOL_A_LINKSTATE_SQI_MAX,
+				data->sqi_max))
+			return -EMSGSIZE;
+	}
+
+	if (data->link_ext_state_provided) {
+		if (nla_put_u8(skb, ETHTOOL_A_LINKSTATE_EXT_STATE,
+			       data->ethtool_link_ext_state_info.link_ext_state))
+			return -EMSGSIZE;
+
+		if (data->ethtool_link_ext_state_info.__link_ext_substate &&
+		    nla_put_u8(skb, ETHTOOL_A_LINKSTATE_EXT_SUBSTATE,
+			       data->ethtool_link_ext_state_info.__link_ext_substate))
+			return -EMSGSIZE;
+	}
+
+	if (data->link_stats.link_down_events != ETHTOOL_STAT_NOT_SET)
+		if (nla_put_u32(skb, ETHTOOL_A_LINKSTATE_EXT_DOWN_CNT,
+				data->link_stats.link_down_events))
+			return -EMSGSIZE;
+
+	return 0;
+}
+
+const struct ethnl_request_ops ethnl_linkstate_request_ops = {
+	.request_cmd		= ETHTOOL_MSG_LINKSTATE_GET,
+	.reply_cmd		= ETHTOOL_MSG_LINKSTATE_GET_REPLY,
+	.hdr_attr		= ETHTOOL_A_LINKSTATE_HEADER,
+	.req_info_size		= sizeof(struct linkstate_req_info),
+	.reply_data_size	= sizeof(struct linkstate_reply_data),
+
+	.prepare_data		= linkstate_prepare_data,
+	.reply_size		= linkstate_reply_size,
+	.fill_reply		= linkstate_fill_reply,
+};