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, 236 insertions, 0 deletions

diff --git a/crypto/md5.c b/crypto/md5.c
new file mode 100644
index 000000000..c167d203c
--- /dev/null
+++ b/crypto/md5.c
@@ -0,0 +1,236 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Crypto API support for MD5 and HMAC-MD5
+ *
+ * Copyright 2025 Google LLC
+ */
+#include <crypto/internal/hash.h>
+#include <crypto/md5.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+/*
+ * Export and import functions.  crypto_shash wants a particular format that
+ * matches that used by some legacy drivers.  It currently is the same as the
+ * library MD5 context, except the value in bytecount must be block-aligned and
+ * the remainder must be stored in an extra u8 appended to the struct.
+ */
+
+#define MD5_SHASH_STATE_SIZE (sizeof(struct md5_ctx) + 1)
+static_assert(sizeof(struct md5_ctx) == sizeof(struct md5_state));
+static_assert(offsetof(struct md5_ctx, state) == offsetof(struct md5_state, hash));
+static_assert(offsetof(struct md5_ctx, bytecount) == offsetof(struct md5_state, byte_count));
+static_assert(offsetof(struct md5_ctx, buf) == offsetof(struct md5_state, block));
+
+static int __crypto_md5_export(const struct md5_ctx *ctx0, void *out)
+{
+	struct md5_ctx ctx = *ctx0;
+	unsigned int partial;
+	u8 *p = out;
+
+	partial = ctx.bytecount % MD5_BLOCK_SIZE;
+	ctx.bytecount -= partial;
+	memcpy(p, &ctx, sizeof(ctx));
+	p += sizeof(ctx);
+	*p = partial;
+	return 0;
+}
+
+static int __crypto_md5_import(struct md5_ctx *ctx, const void *in)
+{
+	const u8 *p = in;
+
+	memcpy(ctx, p, sizeof(*ctx));
+	p += sizeof(*ctx);
+	ctx->bytecount += *p;
+	return 0;
+}
+
+static int __crypto_md5_export_core(const struct md5_ctx *ctx, void *out)
+{
+	memcpy(out, ctx, offsetof(struct md5_ctx, buf));
+	return 0;
+}
+
+static int __crypto_md5_import_core(struct md5_ctx *ctx, const void *in)
+{
+	memcpy(ctx, in, offsetof(struct md5_ctx, buf));
+	return 0;
+}
+
+const u8 md5_zero_message_hash[MD5_DIGEST_SIZE] = {
+	0xd4, 0x1d, 0x8c, 0xd9, 0x8f, 0x00, 0xb2, 0x04,
+	0xe9, 0x80, 0x09, 0x98, 0xec, 0xf8, 0x42, 0x7e,
+};
+EXPORT_SYMBOL_GPL(md5_zero_message_hash);
+
+#define MD5_CTX(desc) ((struct md5_ctx *)shash_desc_ctx(desc))
+
+static int crypto_md5_init(struct shash_desc *desc)
+{
+	md5_init(MD5_CTX(desc));
+	return 0;
+}
+
+static int crypto_md5_update(struct shash_desc *desc,
+			     const u8 *data, unsigned int len)
+{
+	md5_update(MD5_CTX(desc), data, len);
+	return 0;
+}
+
+static int crypto_md5_final(struct shash_desc *desc, u8 *out)
+{
+	md5_final(MD5_CTX(desc), out);
+	return 0;
+}
+
+static int crypto_md5_digest(struct shash_desc *desc,
+			     const u8 *data, unsigned int len, u8 *out)
+{
+	md5(data, len, out);
+	return 0;
+}
+
+static int crypto_md5_export(struct shash_desc *desc, void *out)
+{
+	return __crypto_md5_export(MD5_CTX(desc), out);
+}
+
+static int crypto_md5_import(struct shash_desc *desc, const void *in)
+{
+	return __crypto_md5_import(MD5_CTX(desc), in);
+}
+
+static int crypto_md5_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_md5_export_core(MD5_CTX(desc), out);
+}
+
+static int crypto_md5_import_core(struct shash_desc *desc, const void *in)
+{
+	return __crypto_md5_import_core(MD5_CTX(desc), in);
+}
+
+#define HMAC_MD5_KEY(tfm) ((struct hmac_md5_key *)crypto_shash_ctx(tfm))
+#define HMAC_MD5_CTX(desc) ((struct hmac_md5_ctx *)shash_desc_ctx(desc))
+
+static int crypto_hmac_md5_setkey(struct crypto_shash *tfm,
+				  const u8 *raw_key, unsigned int keylen)
+{
+	hmac_md5_preparekey(HMAC_MD5_KEY(tfm), raw_key, keylen);
+	return 0;
+}
+
+static int crypto_hmac_md5_init(struct shash_desc *desc)
+{
+	hmac_md5_init(HMAC_MD5_CTX(desc), HMAC_MD5_KEY(desc->tfm));
+	return 0;
+}
+
+static int crypto_hmac_md5_update(struct shash_desc *desc,
+				  const u8 *data, unsigned int len)
+{
+	hmac_md5_update(HMAC_MD5_CTX(desc), data, len);
+	return 0;
+}
+
+static int crypto_hmac_md5_final(struct shash_desc *desc, u8 *out)
+{
+	hmac_md5_final(HMAC_MD5_CTX(desc), out);
+	return 0;
+}
+
+static int crypto_hmac_md5_digest(struct shash_desc *desc,
+				  const u8 *data, unsigned int len, u8 *out)
+{
+	hmac_md5(HMAC_MD5_KEY(desc->tfm), data, len, out);
+	return 0;
+}
+
+static int crypto_hmac_md5_export(struct shash_desc *desc, void *out)
+{
+	return __crypto_md5_export(&HMAC_MD5_CTX(desc)->hash_ctx, out);
+}
+
+static int crypto_hmac_md5_import(struct shash_desc *desc, const void *in)
+{
+	struct hmac_md5_ctx *ctx = HMAC_MD5_CTX(desc);
+
+	ctx->ostate = HMAC_MD5_KEY(desc->tfm)->ostate;
+	return __crypto_md5_import(&ctx->hash_ctx, in);
+}
+
+static int crypto_hmac_md5_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_md5_export_core(&HMAC_MD5_CTX(desc)->hash_ctx, out);
+}
+
+static int crypto_hmac_md5_import_core(struct shash_desc *desc, const void *in)
+{
+	struct hmac_md5_ctx *ctx = HMAC_MD5_CTX(desc);
+
+	ctx->ostate = HMAC_MD5_KEY(desc->tfm)->ostate;
+	return __crypto_md5_import_core(&ctx->hash_ctx, in);
+}
+
+static struct shash_alg algs[] = {
+	{
+		.base.cra_name		= "md5",
+		.base.cra_driver_name	= "md5-lib",
+		.base.cra_priority	= 300,
+		.base.cra_blocksize	= MD5_BLOCK_SIZE,
+		.base.cra_module	= THIS_MODULE,
+		.digestsize		= MD5_DIGEST_SIZE,
+		.init			= crypto_md5_init,
+		.update			= crypto_md5_update,
+		.final			= crypto_md5_final,
+		.digest			= crypto_md5_digest,
+		.export			= crypto_md5_export,
+		.import			= crypto_md5_import,
+		.export_core		= crypto_md5_export_core,
+		.import_core		= crypto_md5_import_core,
+		.descsize		= sizeof(struct md5_ctx),
+		.statesize		= MD5_SHASH_STATE_SIZE,
+	},
+	{
+		.base.cra_name		= "hmac(md5)",
+		.base.cra_driver_name	= "hmac-md5-lib",
+		.base.cra_priority	= 300,
+		.base.cra_blocksize	= MD5_BLOCK_SIZE,
+		.base.cra_ctxsize	= sizeof(struct hmac_md5_key),
+		.base.cra_module	= THIS_MODULE,
+		.digestsize		= MD5_DIGEST_SIZE,
+		.setkey			= crypto_hmac_md5_setkey,
+		.init			= crypto_hmac_md5_init,
+		.update			= crypto_hmac_md5_update,
+		.final			= crypto_hmac_md5_final,
+		.digest			= crypto_hmac_md5_digest,
+		.export			= crypto_hmac_md5_export,
+		.import			= crypto_hmac_md5_import,
+		.export_core		= crypto_hmac_md5_export_core,
+		.import_core		= crypto_hmac_md5_import_core,
+		.descsize		= sizeof(struct hmac_md5_ctx),
+		.statesize		= MD5_SHASH_STATE_SIZE,
+	},
+};
+
+static int __init crypto_md5_mod_init(void)
+{
+	return crypto_register_shashes(algs, ARRAY_SIZE(algs));
+}
+module_init(crypto_md5_mod_init);
+
+static void __exit crypto_md5_mod_exit(void)
+{
+	crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
+}
+module_exit(crypto_md5_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Crypto API support for MD5 and HMAC-MD5");
+
+MODULE_ALIAS_CRYPTO("md5");
+MODULE_ALIAS_CRYPTO("md5-lib");
+MODULE_ALIAS_CRYPTO("hmac(md5)");
+MODULE_ALIAS_CRYPTO("hmac-md5-lib");