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, 191 insertions, 0 deletions

diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h
new file mode 100644
index 000000000..2cc5d416b
--- /dev/null
+++ b/include/net/inet6_hashtables.h
@@ -0,0 +1,191 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ * Authors:	Lotsa people, from code originally in tcp
+ */
+
+#ifndef _INET6_HASHTABLES_H
+#define _INET6_HASHTABLES_H
+
+
+#if IS_ENABLED(CONFIG_IPV6)
+#include <linux/in6.h>
+#include <linux/ipv6.h>
+#include <linux/types.h>
+#include <linux/jhash.h>
+
+#include <net/inet_sock.h>
+
+#include <net/ipv6.h>
+#include <net/netns/hash.h>
+
+struct inet_hashinfo;
+
+void inet6_init_ehash_secret(void);
+
+static inline unsigned int __inet6_ehashfn(const u32 lhash,
+				    const u16 lport,
+				    const u32 fhash,
+				    const __be16 fport,
+				    const u32 initval)
+{
+	const u32 ports = (((u32)lport) << 16) | (__force u32)fport;
+	return jhash_3words(lhash, fhash, ports, initval);
+}
+
+/*
+ * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
+ * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
+ *
+ * The sockhash lock must be held as a reader here.
+ */
+struct sock *__inet6_lookup_established(const struct net *net,
+					const struct in6_addr *saddr,
+					const __be16 sport,
+					const struct in6_addr *daddr,
+					const u16 hnum, const int dif,
+					const int sdif);
+
+typedef u32 (inet6_ehashfn_t)(const struct net *net,
+			       const struct in6_addr *laddr, const u16 lport,
+			       const struct in6_addr *faddr, const __be16 fport);
+
+inet6_ehashfn_t inet6_ehashfn;
+
+INDIRECT_CALLABLE_DECLARE(inet6_ehashfn_t udp6_ehashfn);
+
+struct sock *inet6_lookup_reuseport(const struct net *net, struct sock *sk,
+				    struct sk_buff *skb, int doff,
+				    const struct in6_addr *saddr,
+				    __be16 sport,
+				    const struct in6_addr *daddr,
+				    unsigned short hnum,
+				    inet6_ehashfn_t *ehashfn);
+
+struct sock *inet6_lookup_listener(const struct net *net,
+				   struct sk_buff *skb, int doff,
+				   const struct in6_addr *saddr,
+				   const __be16 sport,
+				   const struct in6_addr *daddr,
+				   const unsigned short hnum,
+				   const int dif, const int sdif);
+
+struct sock *inet6_lookup_run_sk_lookup(const struct net *net,
+					int protocol,
+					struct sk_buff *skb, int doff,
+					const struct in6_addr *saddr,
+					const __be16 sport,
+					const struct in6_addr *daddr,
+					const u16 hnum, const int dif,
+					inet6_ehashfn_t *ehashfn);
+
+static inline struct sock *__inet6_lookup(const struct net *net,
+					  struct sk_buff *skb, int doff,
+					  const struct in6_addr *saddr,
+					  const __be16 sport,
+					  const struct in6_addr *daddr,
+					  const u16 hnum,
+					  const int dif, const int sdif,
+					  bool *refcounted)
+{
+	struct sock *sk = __inet6_lookup_established(net, saddr, sport,
+						     daddr, hnum,
+						     dif, sdif);
+	*refcounted = true;
+	if (sk)
+		return sk;
+	*refcounted = false;
+	return inet6_lookup_listener(net, skb, doff, saddr, sport,
+				     daddr, hnum, dif, sdif);
+}
+
+static inline
+struct sock *inet6_steal_sock(struct net *net, struct sk_buff *skb, int doff,
+			      const struct in6_addr *saddr, const __be16 sport,
+			      const struct in6_addr *daddr, const __be16 dport,
+			      bool *refcounted, inet6_ehashfn_t *ehashfn)
+{
+	struct sock *sk, *reuse_sk;
+	bool prefetched;
+
+	sk = skb_steal_sock(skb, refcounted, &prefetched);
+	if (!sk)
+		return NULL;
+
+	if (!prefetched || !sk_fullsock(sk))
+		return sk;
+
+	if (sk->sk_protocol == IPPROTO_TCP) {
+		if (sk->sk_state != TCP_LISTEN)
+			return sk;
+	} else if (sk->sk_protocol == IPPROTO_UDP) {
+		if (sk->sk_state != TCP_CLOSE)
+			return sk;
+	} else {
+		return sk;
+	}
+
+	reuse_sk = inet6_lookup_reuseport(net, sk, skb, doff,
+					  saddr, sport, daddr, ntohs(dport),
+					  ehashfn);
+	if (!reuse_sk)
+		return sk;
+
+	/* We've chosen a new reuseport sock which is never refcounted. This
+	 * implies that sk also isn't refcounted.
+	 */
+	WARN_ON_ONCE(*refcounted);
+
+	return reuse_sk;
+}
+
+static inline struct sock *__inet6_lookup_skb(struct sk_buff *skb, int doff,
+					      const __be16 sport,
+					      const __be16 dport,
+					      int iif, int sdif,
+					      bool *refcounted)
+{
+	struct net *net = skb_dst_dev_net_rcu(skb);
+	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
+	struct sock *sk;
+
+	sk = inet6_steal_sock(net, skb, doff, &ip6h->saddr, sport, &ip6h->daddr, dport,
+			      refcounted, inet6_ehashfn);
+	if (IS_ERR(sk))
+		return NULL;
+	if (sk)
+		return sk;
+
+	return __inet6_lookup(net, skb, doff, &ip6h->saddr, sport,
+			      &ip6h->daddr, ntohs(dport),
+			      iif, sdif, refcounted);
+}
+
+struct sock *inet6_lookup(const struct net *net, struct sk_buff *skb, int doff,
+			  const struct in6_addr *saddr, const __be16 sport,
+			  const struct in6_addr *daddr, const __be16 dport,
+			  const int dif);
+
+static inline bool inet6_match(const struct net *net, const struct sock *sk,
+			       const struct in6_addr *saddr,
+			       const struct in6_addr *daddr,
+			       const __portpair ports,
+			       const int dif, const int sdif)
+{
+	if (!net_eq(sock_net(sk), net) ||
+	    sk->sk_family != AF_INET6 ||
+	    READ_ONCE(sk->sk_portpair) != ports ||
+	    !ipv6_addr_equal(&sk->sk_v6_daddr, saddr) ||
+	    !ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
+		return false;
+
+	/* READ_ONCE() paired with WRITE_ONCE() in sock_bindtoindex_locked() */
+	return inet_sk_bound_dev_eq(net, READ_ONCE(sk->sk_bound_dev_if), dif,
+				    sdif);
+}
+#endif /* IS_ENABLED(CONFIG_IPV6) */
+
+#endif /* _INET6_HASHTABLES_H */