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, 168 insertions, 0 deletions

diff --git a/include/crypto/krb5.h b/include/crypto/krb5.h
new file mode 100644
index 000000000..aac3ecf88
--- /dev/null
+++ b/include/crypto/krb5.h
@@ -0,0 +1,168 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Kerberos 5 crypto
+ *
+ * Copyright (C) 2025 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#ifndef _CRYPTO_KRB5_H
+#define _CRYPTO_KRB5_H
+
+#include <linux/crypto.h>
+#include <crypto/aead.h>
+#include <crypto/hash.h>
+
+struct crypto_shash;
+struct scatterlist;
+
+/*
+ * Per Kerberos v5 protocol spec crypto types from the wire.  These get mapped
+ * to linux kernel crypto routines.
+ */
+#define KRB5_ENCTYPE_NULL			0x0000
+#define KRB5_ENCTYPE_DES_CBC_CRC		0x0001	/* DES cbc mode with CRC-32 */
+#define KRB5_ENCTYPE_DES_CBC_MD4		0x0002	/* DES cbc mode with RSA-MD4 */
+#define KRB5_ENCTYPE_DES_CBC_MD5		0x0003	/* DES cbc mode with RSA-MD5 */
+#define KRB5_ENCTYPE_DES_CBC_RAW		0x0004	/* DES cbc mode raw */
+/* XXX deprecated? */
+#define KRB5_ENCTYPE_DES3_CBC_SHA		0x0005	/* DES-3 cbc mode with NIST-SHA */
+#define KRB5_ENCTYPE_DES3_CBC_RAW		0x0006	/* DES-3 cbc mode raw */
+#define KRB5_ENCTYPE_DES_HMAC_SHA1		0x0008
+#define KRB5_ENCTYPE_DES3_CBC_SHA1		0x0010
+#define KRB5_ENCTYPE_AES128_CTS_HMAC_SHA1_96	0x0011
+#define KRB5_ENCTYPE_AES256_CTS_HMAC_SHA1_96	0x0012
+#define KRB5_ENCTYPE_AES128_CTS_HMAC_SHA256_128	0x0013
+#define KRB5_ENCTYPE_AES256_CTS_HMAC_SHA384_192	0x0014
+#define KRB5_ENCTYPE_ARCFOUR_HMAC		0x0017
+#define KRB5_ENCTYPE_ARCFOUR_HMAC_EXP		0x0018
+#define KRB5_ENCTYPE_CAMELLIA128_CTS_CMAC	0x0019
+#define KRB5_ENCTYPE_CAMELLIA256_CTS_CMAC	0x001a
+#define KRB5_ENCTYPE_UNKNOWN			0x01ff
+
+#define KRB5_CKSUMTYPE_CRC32			0x0001
+#define KRB5_CKSUMTYPE_RSA_MD4			0x0002
+#define KRB5_CKSUMTYPE_RSA_MD4_DES		0x0003
+#define KRB5_CKSUMTYPE_DESCBC			0x0004
+#define KRB5_CKSUMTYPE_RSA_MD5			0x0007
+#define KRB5_CKSUMTYPE_RSA_MD5_DES		0x0008
+#define KRB5_CKSUMTYPE_NIST_SHA			0x0009
+#define KRB5_CKSUMTYPE_HMAC_SHA1_DES3		0x000c
+#define KRB5_CKSUMTYPE_HMAC_SHA1_96_AES128	0x000f
+#define KRB5_CKSUMTYPE_HMAC_SHA1_96_AES256	0x0010
+#define KRB5_CKSUMTYPE_CMAC_CAMELLIA128		0x0011
+#define KRB5_CKSUMTYPE_CMAC_CAMELLIA256		0x0012
+#define KRB5_CKSUMTYPE_HMAC_SHA256_128_AES128	0x0013
+#define KRB5_CKSUMTYPE_HMAC_SHA384_192_AES256	0x0014
+#define KRB5_CKSUMTYPE_HMAC_MD5_ARCFOUR		-138 /* Microsoft md5 hmac cksumtype */
+
+/*
+ * Constants used for key derivation
+ */
+/* from rfc3961 */
+#define KEY_USAGE_SEED_CHECKSUM         (0x99)
+#define KEY_USAGE_SEED_ENCRYPTION       (0xAA)
+#define KEY_USAGE_SEED_INTEGRITY        (0x55)
+
+/*
+ * Standard Kerberos error codes.
+ */
+#define KRB5_PROG_KEYTYPE_NOSUPP		-1765328233
+
+/*
+ * Mode of operation.
+ */
+enum krb5_crypto_mode {
+	KRB5_CHECKSUM_MODE,	/* Checksum only */
+	KRB5_ENCRYPT_MODE,	/* Fully encrypted, possibly with integrity checksum */
+};
+
+struct krb5_buffer {
+	unsigned int	len;
+	void		*data;
+};
+
+/*
+ * Kerberos encoding type definition.
+ */
+struct krb5_enctype {
+	int		etype;		/* Encryption (key) type */
+	int		ctype;		/* Checksum type */
+	const char	*name;		/* "Friendly" name */
+	const char	*encrypt_name;	/* Crypto encrypt+checksum name */
+	const char	*cksum_name;	/* Crypto checksum name */
+	const char	*hash_name;	/* Crypto hash name */
+	const char	*derivation_enc; /* Cipher used in key derivation */
+	u16		block_len;	/* Length of encryption block */
+	u16		conf_len;	/* Length of confounder (normally == block_len) */
+	u16		cksum_len;	/* Length of checksum */
+	u16		key_bytes;	/* Length of raw key, in bytes */
+	u16		key_len;	/* Length of final key, in bytes */
+	u16		hash_len;	/* Length of hash in bytes */
+	u16		prf_len;	/* Length of PRF() result in bytes */
+	u16		Kc_len;		/* Length of Kc in bytes */
+	u16		Ke_len;		/* Length of Ke in bytes */
+	u16		Ki_len;		/* Length of Ki in bytes */
+	bool		keyed_cksum;	/* T if a keyed cksum */
+
+	const struct krb5_crypto_profile *profile;
+
+	int (*random_to_key)(const struct krb5_enctype *krb5,
+			     const struct krb5_buffer *in,
+			     struct krb5_buffer *out);	/* complete key generation */
+};
+
+/*
+ * krb5_api.c
+ */
+const struct krb5_enctype *crypto_krb5_find_enctype(u32 enctype);
+size_t crypto_krb5_how_much_buffer(const struct krb5_enctype *krb5,
+				   enum krb5_crypto_mode mode,
+				   size_t data_size, size_t *_offset);
+size_t crypto_krb5_how_much_data(const struct krb5_enctype *krb5,
+				 enum krb5_crypto_mode mode,
+				 size_t *_buffer_size, size_t *_offset);
+int crypto_krb5_where_is_the_data(const struct krb5_enctype *krb5,
+				  enum krb5_crypto_mode mode,
+				  size_t *_offset, size_t *_len);
+int crypto_krb5_check_data_len(const struct krb5_enctype *krb5,
+			       enum krb5_crypto_mode mode,
+			       size_t len, size_t min_content);
+struct crypto_aead *crypto_krb5_prepare_encryption(const struct krb5_enctype *krb5,
+						   const struct krb5_buffer *TK,
+						   u32 usage, gfp_t gfp);
+struct crypto_shash *crypto_krb5_prepare_checksum(const struct krb5_enctype *krb5,
+						  const struct krb5_buffer *TK,
+						  u32 usage, gfp_t gfp);
+ssize_t crypto_krb5_encrypt(const struct krb5_enctype *krb5,
+			    struct crypto_aead *aead,
+			    struct scatterlist *sg, unsigned int nr_sg,
+			    size_t sg_len,
+			    size_t data_offset, size_t data_len,
+			    bool preconfounded);
+int crypto_krb5_decrypt(const struct krb5_enctype *krb5,
+			struct crypto_aead *aead,
+			struct scatterlist *sg, unsigned int nr_sg,
+			size_t *_offset, size_t *_len);
+ssize_t crypto_krb5_get_mic(const struct krb5_enctype *krb5,
+			    struct crypto_shash *shash,
+			    const struct krb5_buffer *metadata,
+			    struct scatterlist *sg, unsigned int nr_sg,
+			    size_t sg_len,
+			    size_t data_offset, size_t data_len);
+int crypto_krb5_verify_mic(const struct krb5_enctype *krb5,
+			   struct crypto_shash *shash,
+			   const struct krb5_buffer *metadata,
+			   struct scatterlist *sg, unsigned int nr_sg,
+			   size_t *_offset, size_t *_len);
+
+/*
+ * krb5_kdf.c
+ */
+int crypto_krb5_calc_PRFplus(const struct krb5_enctype *krb5,
+			     const struct krb5_buffer *K,
+			     unsigned int L,
+			     const struct krb5_buffer *S,
+			     struct krb5_buffer *result,
+			     gfp_t gfp);
+
+#endif /* _CRYPTO_KRB5_H */