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, 182 insertions, 0 deletions

diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
new file mode 100644
index 000000000..365925c9d
--- /dev/null
+++ b/include/net/inet_frag.h
@@ -0,0 +1,182 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __NET_FRAG_H__
+#define __NET_FRAG_H__
+
+#include <linux/rhashtable-types.h>
+#include <linux/completion.h>
+#include <linux/in6.h>
+#include <linux/rbtree_types.h>
+#include <linux/refcount.h>
+#include <net/dropreason-core.h>
+
+/* Per netns frag queues directory */
+struct fqdir {
+	/* sysctls */
+	long			high_thresh;
+	long			low_thresh;
+	int			timeout;
+	int			max_dist;
+	struct inet_frags	*f;
+	struct net		*net;
+	bool			dead;
+
+	struct rhashtable       rhashtable ____cacheline_aligned_in_smp;
+
+	/* Keep atomic mem on separate cachelines in structs that include it */
+	atomic_long_t		mem ____cacheline_aligned_in_smp;
+	struct work_struct	destroy_work;
+	struct llist_node	free_list;
+};
+
+/**
+ * enum: fragment queue flags
+ *
+ * @INET_FRAG_FIRST_IN: first fragment has arrived
+ * @INET_FRAG_LAST_IN: final fragment has arrived
+ * @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction
+ * @INET_FRAG_HASH_DEAD: inet_frag_kill() has not removed fq from rhashtable
+ * @INET_FRAG_DROP: if skbs must be dropped (instead of being consumed)
+ */
+enum {
+	INET_FRAG_FIRST_IN	= BIT(0),
+	INET_FRAG_LAST_IN	= BIT(1),
+	INET_FRAG_COMPLETE	= BIT(2),
+	INET_FRAG_HASH_DEAD	= BIT(3),
+	INET_FRAG_DROP		= BIT(4),
+};
+
+struct frag_v4_compare_key {
+	__be32		saddr;
+	__be32		daddr;
+	u32		user;
+	u32		vif;
+	__be16		id;
+	u16		protocol;
+};
+
+struct frag_v6_compare_key {
+	struct in6_addr	saddr;
+	struct in6_addr	daddr;
+	u32		user;
+	__be32		id;
+	u32		iif;
+};
+
+/**
+ * struct inet_frag_queue - fragment queue
+ *
+ * @node: rhash node
+ * @key: keys identifying this frag.
+ * @timer: queue expiration timer
+ * @lock: spinlock protecting this frag
+ * @refcnt: reference count of the queue
+ * @rb_fragments: received fragments rb-tree root
+ * @fragments_tail: received fragments tail
+ * @last_run_head: the head of the last "run". see ip_fragment.c
+ * @stamp: timestamp of the last received fragment
+ * @len: total length of the original datagram
+ * @meat: length of received fragments so far
+ * @tstamp_type: stamp has a mono delivery time (EDT)
+ * @flags: fragment queue flags
+ * @max_size: maximum received fragment size
+ * @fqdir: pointer to struct fqdir
+ * @rcu: rcu head for freeing deferall
+ */
+struct inet_frag_queue {
+	struct rhash_head	node;
+	union {
+		struct frag_v4_compare_key v4;
+		struct frag_v6_compare_key v6;
+	} key;
+	struct timer_list	timer;
+	spinlock_t		lock;
+	refcount_t		refcnt;
+	struct rb_root		rb_fragments;
+	struct sk_buff		*fragments_tail;
+	struct sk_buff		*last_run_head;
+	ktime_t			stamp;
+	int			len;
+	int			meat;
+	u8			tstamp_type;
+	__u8			flags;
+	u16			max_size;
+	struct fqdir		*fqdir;
+	struct rcu_head		rcu;
+};
+
+struct inet_frags {
+	unsigned int		qsize;
+
+	void			(*constructor)(struct inet_frag_queue *q,
+					       const void *arg);
+	void			(*destructor)(struct inet_frag_queue *);
+	void			(*frag_expire)(struct timer_list *t);
+	struct kmem_cache	*frags_cachep;
+	const char		*frags_cache_name;
+	struct rhashtable_params rhash_params;
+	refcount_t		refcnt;
+	struct completion	completion;
+};
+
+int inet_frags_init(struct inet_frags *);
+void inet_frags_fini(struct inet_frags *);
+
+int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net);
+
+void fqdir_pre_exit(struct fqdir *fqdir);
+void fqdir_exit(struct fqdir *fqdir);
+
+void inet_frag_kill(struct inet_frag_queue *q, int *refs);
+void inet_frag_destroy(struct inet_frag_queue *q);
+struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key);
+
+void inet_frag_queue_flush(struct inet_frag_queue *q,
+			   enum skb_drop_reason reason);
+
+static inline void inet_frag_putn(struct inet_frag_queue *q, int refs)
+{
+	if (refs && refcount_sub_and_test(refs, &q->refcnt))
+		inet_frag_destroy(q);
+}
+
+/* Memory Tracking Functions. */
+
+static inline long frag_mem_limit(const struct fqdir *fqdir)
+{
+	return atomic_long_read(&fqdir->mem);
+}
+
+static inline void sub_frag_mem_limit(struct fqdir *fqdir, long val)
+{
+	atomic_long_sub(val, &fqdir->mem);
+}
+
+static inline void add_frag_mem_limit(struct fqdir *fqdir, long val)
+{
+	atomic_long_add(val, &fqdir->mem);
+}
+
+/* RFC 3168 support :
+ * We want to check ECN values of all fragments, do detect invalid combinations.
+ * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
+ */
+#define	IPFRAG_ECN_NOT_ECT	0x01 /* one frag had ECN_NOT_ECT */
+#define	IPFRAG_ECN_ECT_1	0x02 /* one frag had ECN_ECT_1 */
+#define	IPFRAG_ECN_ECT_0	0x04 /* one frag had ECN_ECT_0 */
+#define	IPFRAG_ECN_CE		0x08 /* one frag had ECN_CE */
+
+extern const u8 ip_frag_ecn_table[16];
+
+/* Return values of inet_frag_queue_insert() */
+#define IPFRAG_OK	0
+#define IPFRAG_DUP	1
+#define IPFRAG_OVERLAP	2
+int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
+			   int offset, int end);
+void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
+			      struct sk_buff *parent);
+void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
+			    void *reasm_data, bool try_coalesce);
+struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q);
+
+#endif