sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling buggrafted

alb_break_llc() decides whether to break LLC preference during active
load balance. It does so by testing that every runnable fair task on the
source rq prefers its LLC:

	env->src_rq->nr_pref_llc_running == env->src_rq->cfs.h_nr_runnable

But the two counters cover different sets. nr_pref_llc_running is updated
in account_llc_enqueue()/account_llc_dequeue(), next to cfs_rq->nr_queued,
so it follows queued tasks. h_nr_runnable is updated in set_delayed()/
clear_delayed() and drops delay-dequeued tasks.

So under DELAY_DEQUEUE, a preferring task that goes to sleep stays counted
in nr_pref_llc_running while h_nr_runnable falls. The equality then breaks,
alb_break_llc() returns false, and active balance is free to pull a task
off its preferred LLC. Active balance only moves runnable tasks, and this
is the only LLC check it consults: once the stopper runs, LBF_ACTIVE_LB
skips the per-task test in can_migrate_task(). The runnable set is the one
we want.

Fix it on the counter side. A task should be counted in
nr_pref_llc_running exactly while it is both queued on its preferred LLC
(pref_llc_queued) and runnable (!sched_delayed). Define that membership
once in task_pref_llc_runnable(), and adjust the counter only through
pref_llc_running_inc()/pref_llc_running_dec() from the four sites that
change either input: account_llc_enqueue(), account_llc_dequeue(),
set_delayed() and clear_delayed(). Gating every update on the same
predicate keeps the delay, wake and dequeue paths from double-counting
or underflowing; see the comments at those sites for the ordering.

nr_llc_running and sd->llc_counts are not touched and stay on queued
semantics.

Fixes: 714059f79ff0 ("sched/cache: Handle moving single tasks to/from their preferred LLC")
Closes: https://lore.kernel.org/lkml/20260827135000.735138-1-zhanxusheng@xiaomi.com/
Reported-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Suggested-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kayra Cizmeci <kayracizmeci@gmail.com>
Cc: <stable@kernel.org> # v7.2.x
Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com

1 files changed, 419 insertions, 0 deletions

diff --git a/crypto/sha256.c b/crypto/sha256.c
new file mode 100644
index 000000000..fb81defe0
--- /dev/null
+++ b/crypto/sha256.c
@@ -0,0 +1,419 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Crypto API support for SHA-224, SHA-256, HMAC-SHA224, and HMAC-SHA256
+ *
+ * Copyright (c) Jean-Luc Cooke <jlcooke@certainkey.com>
+ * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ * SHA224 Support Copyright 2007 Intel Corporation <jonathan.lynch@intel.com>
+ * Copyright 2025 Google LLC
+ */
+#include <crypto/internal/hash.h>
+#include <crypto/sha2.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 SHA 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 SHA256_SHASH_STATE_SIZE 105
+static_assert(offsetof(struct __sha256_ctx, state) == 0);
+static_assert(offsetof(struct __sha256_ctx, bytecount) == 32);
+static_assert(offsetof(struct __sha256_ctx, buf) == 40);
+static_assert(sizeof(struct __sha256_ctx) + 1 == SHA256_SHASH_STATE_SIZE);
+
+static int __crypto_sha256_export(const struct __sha256_ctx *ctx0, void *out)
+{
+	struct __sha256_ctx ctx = *ctx0;
+	unsigned int partial;
+	u8 *p = out;
+
+	partial = ctx.bytecount % SHA256_BLOCK_SIZE;
+	ctx.bytecount -= partial;
+	memcpy(p, &ctx, sizeof(ctx));
+	p += sizeof(ctx);
+	*p = partial;
+	return 0;
+}
+
+static int __crypto_sha256_import(struct __sha256_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_sha256_export_core(const struct __sha256_ctx *ctx,
+				       void *out)
+{
+	memcpy(out, ctx, offsetof(struct __sha256_ctx, buf));
+	return 0;
+}
+
+static int __crypto_sha256_import_core(struct __sha256_ctx *ctx, const void *in)
+{
+	memcpy(ctx, in, offsetof(struct __sha256_ctx, buf));
+	return 0;
+}
+
+/* SHA-224 */
+
+const u8 sha224_zero_message_hash[SHA224_DIGEST_SIZE] = {
+	0xd1, 0x4a, 0x02, 0x8c, 0x2a, 0x3a, 0x2b, 0xc9, 0x47,
+	0x61, 0x02, 0xbb, 0x28, 0x82, 0x34, 0xc4, 0x15, 0xa2,
+	0xb0, 0x1f, 0x82, 0x8e, 0xa6, 0x2a, 0xc5, 0xb3, 0xe4,
+	0x2f
+};
+EXPORT_SYMBOL_GPL(sha224_zero_message_hash);
+
+#define SHA224_CTX(desc) ((struct sha224_ctx *)shash_desc_ctx(desc))
+
+static int crypto_sha224_init(struct shash_desc *desc)
+{
+	sha224_init(SHA224_CTX(desc));
+	return 0;
+}
+
+static int crypto_sha224_update(struct shash_desc *desc,
+				const u8 *data, unsigned int len)
+{
+	sha224_update(SHA224_CTX(desc), data, len);
+	return 0;
+}
+
+static int crypto_sha224_final(struct shash_desc *desc, u8 *out)
+{
+	sha224_final(SHA224_CTX(desc), out);
+	return 0;
+}
+
+static int crypto_sha224_digest(struct shash_desc *desc,
+				const u8 *data, unsigned int len, u8 *out)
+{
+	sha224(data, len, out);
+	return 0;
+}
+
+static int crypto_sha224_export(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha256_export(&SHA224_CTX(desc)->ctx, out);
+}
+
+static int crypto_sha224_import(struct shash_desc *desc, const void *in)
+{
+	return __crypto_sha256_import(&SHA224_CTX(desc)->ctx, in);
+}
+
+static int crypto_sha224_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha256_export_core(&SHA224_CTX(desc)->ctx, out);
+}
+
+static int crypto_sha224_import_core(struct shash_desc *desc, const void *in)
+{
+	return __crypto_sha256_import_core(&SHA224_CTX(desc)->ctx, in);
+}
+
+/* SHA-256 */
+
+const u8 sha256_zero_message_hash[SHA256_DIGEST_SIZE] = {
+	0xe3, 0xb0, 0xc4, 0x42, 0x98, 0xfc, 0x1c, 0x14,
+	0x9a, 0xfb, 0xf4, 0xc8, 0x99, 0x6f, 0xb9, 0x24,
+	0x27, 0xae, 0x41, 0xe4, 0x64, 0x9b, 0x93, 0x4c,
+	0xa4, 0x95, 0x99, 0x1b, 0x78, 0x52, 0xb8, 0x55
+};
+EXPORT_SYMBOL_GPL(sha256_zero_message_hash);
+
+#define SHA256_CTX(desc) ((struct sha256_ctx *)shash_desc_ctx(desc))
+
+static int crypto_sha256_init(struct shash_desc *desc)
+{
+	sha256_init(SHA256_CTX(desc));
+	return 0;
+}
+
+static int crypto_sha256_update(struct shash_desc *desc,
+				const u8 *data, unsigned int len)
+{
+	sha256_update(SHA256_CTX(desc), data, len);
+	return 0;
+}
+
+static int crypto_sha256_final(struct shash_desc *desc, u8 *out)
+{
+	sha256_final(SHA256_CTX(desc), out);
+	return 0;
+}
+
+static int crypto_sha256_digest(struct shash_desc *desc,
+				const u8 *data, unsigned int len, u8 *out)
+{
+	sha256(data, len, out);
+	return 0;
+}
+
+static int crypto_sha256_export(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha256_export(&SHA256_CTX(desc)->ctx, out);
+}
+
+static int crypto_sha256_import(struct shash_desc *desc, const void *in)
+{
+	return __crypto_sha256_import(&SHA256_CTX(desc)->ctx, in);
+}
+
+static int crypto_sha256_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha256_export_core(&SHA256_CTX(desc)->ctx, out);
+}
+
+static int crypto_sha256_import_core(struct shash_desc *desc, const void *in)
+{
+	return __crypto_sha256_import_core(&SHA256_CTX(desc)->ctx, in);
+}
+
+/* HMAC-SHA224 */
+
+#define HMAC_SHA224_KEY(tfm) ((struct hmac_sha224_key *)crypto_shash_ctx(tfm))
+#define HMAC_SHA224_CTX(desc) ((struct hmac_sha224_ctx *)shash_desc_ctx(desc))
+
+static int crypto_hmac_sha224_setkey(struct crypto_shash *tfm,
+				     const u8 *raw_key, unsigned int keylen)
+{
+	hmac_sha224_preparekey(HMAC_SHA224_KEY(tfm), raw_key, keylen);
+	return 0;
+}
+
+static int crypto_hmac_sha224_init(struct shash_desc *desc)
+{
+	hmac_sha224_init(HMAC_SHA224_CTX(desc), HMAC_SHA224_KEY(desc->tfm));
+	return 0;
+}
+
+static int crypto_hmac_sha224_update(struct shash_desc *desc,
+				     const u8 *data, unsigned int len)
+{
+	hmac_sha224_update(HMAC_SHA224_CTX(desc), data, len);
+	return 0;
+}
+
+static int crypto_hmac_sha224_final(struct shash_desc *desc, u8 *out)
+{
+	hmac_sha224_final(HMAC_SHA224_CTX(desc), out);
+	return 0;
+}
+
+static int crypto_hmac_sha224_digest(struct shash_desc *desc,
+				     const u8 *data, unsigned int len,
+				     u8 *out)
+{
+	hmac_sha224(HMAC_SHA224_KEY(desc->tfm), data, len, out);
+	return 0;
+}
+
+static int crypto_hmac_sha224_export(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha256_export(&HMAC_SHA224_CTX(desc)->ctx.sha_ctx, out);
+}
+
+static int crypto_hmac_sha224_import(struct shash_desc *desc, const void *in)
+{
+	struct hmac_sha224_ctx *ctx = HMAC_SHA224_CTX(desc);
+
+	ctx->ctx.ostate = HMAC_SHA224_KEY(desc->tfm)->key.ostate;
+	return __crypto_sha256_import(&ctx->ctx.sha_ctx, in);
+}
+
+static int crypto_hmac_sha224_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha256_export_core(&HMAC_SHA224_CTX(desc)->ctx.sha_ctx,
+					   out);
+}
+
+static int crypto_hmac_sha224_import_core(struct shash_desc *desc,
+					  const void *in)
+{
+	struct hmac_sha224_ctx *ctx = HMAC_SHA224_CTX(desc);
+
+	ctx->ctx.ostate = HMAC_SHA224_KEY(desc->tfm)->key.ostate;
+	return __crypto_sha256_import_core(&ctx->ctx.sha_ctx, in);
+}
+
+/* HMAC-SHA256 */
+
+#define HMAC_SHA256_KEY(tfm) ((struct hmac_sha256_key *)crypto_shash_ctx(tfm))
+#define HMAC_SHA256_CTX(desc) ((struct hmac_sha256_ctx *)shash_desc_ctx(desc))
+
+static int crypto_hmac_sha256_setkey(struct crypto_shash *tfm,
+				     const u8 *raw_key, unsigned int keylen)
+{
+	hmac_sha256_preparekey(HMAC_SHA256_KEY(tfm), raw_key, keylen);
+	return 0;
+}
+
+static int crypto_hmac_sha256_init(struct shash_desc *desc)
+{
+	hmac_sha256_init(HMAC_SHA256_CTX(desc), HMAC_SHA256_KEY(desc->tfm));
+	return 0;
+}
+
+static int crypto_hmac_sha256_update(struct shash_desc *desc,
+				     const u8 *data, unsigned int len)
+{
+	hmac_sha256_update(HMAC_SHA256_CTX(desc), data, len);
+	return 0;
+}
+
+static int crypto_hmac_sha256_final(struct shash_desc *desc, u8 *out)
+{
+	hmac_sha256_final(HMAC_SHA256_CTX(desc), out);
+	return 0;
+}
+
+static int crypto_hmac_sha256_digest(struct shash_desc *desc,
+				     const u8 *data, unsigned int len,
+				     u8 *out)
+{
+	hmac_sha256(HMAC_SHA256_KEY(desc->tfm), data, len, out);
+	return 0;
+}
+
+static int crypto_hmac_sha256_export(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha256_export(&HMAC_SHA256_CTX(desc)->ctx.sha_ctx, out);
+}
+
+static int crypto_hmac_sha256_import(struct shash_desc *desc, const void *in)
+{
+	struct hmac_sha256_ctx *ctx = HMAC_SHA256_CTX(desc);
+
+	ctx->ctx.ostate = HMAC_SHA256_KEY(desc->tfm)->key.ostate;
+	return __crypto_sha256_import(&ctx->ctx.sha_ctx, in);
+}
+
+static int crypto_hmac_sha256_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha256_export_core(&HMAC_SHA256_CTX(desc)->ctx.sha_ctx,
+					   out);
+}
+
+static int crypto_hmac_sha256_import_core(struct shash_desc *desc,
+					  const void *in)
+{
+	struct hmac_sha256_ctx *ctx = HMAC_SHA256_CTX(desc);
+
+	ctx->ctx.ostate = HMAC_SHA256_KEY(desc->tfm)->key.ostate;
+	return __crypto_sha256_import_core(&ctx->ctx.sha_ctx, in);
+}
+
+/* Algorithm definitions */
+
+static struct shash_alg algs[] = {
+	{
+		.base.cra_name		= "sha224",
+		.base.cra_driver_name	= "sha224-lib",
+		.base.cra_priority	= 300,
+		.base.cra_blocksize	= SHA224_BLOCK_SIZE,
+		.base.cra_module	= THIS_MODULE,
+		.digestsize		= SHA224_DIGEST_SIZE,
+		.init			= crypto_sha224_init,
+		.update			= crypto_sha224_update,
+		.final			= crypto_sha224_final,
+		.digest			= crypto_sha224_digest,
+		.export			= crypto_sha224_export,
+		.import			= crypto_sha224_import,
+		.export_core		= crypto_sha224_export_core,
+		.import_core		= crypto_sha224_import_core,
+		.descsize		= sizeof(struct sha224_ctx),
+		.statesize		= SHA256_SHASH_STATE_SIZE,
+	},
+	{
+		.base.cra_name		= "sha256",
+		.base.cra_driver_name	= "sha256-lib",
+		.base.cra_priority	= 300,
+		.base.cra_blocksize	= SHA256_BLOCK_SIZE,
+		.base.cra_module	= THIS_MODULE,
+		.digestsize		= SHA256_DIGEST_SIZE,
+		.init			= crypto_sha256_init,
+		.update			= crypto_sha256_update,
+		.final			= crypto_sha256_final,
+		.digest			= crypto_sha256_digest,
+		.export			= crypto_sha256_export,
+		.import			= crypto_sha256_import,
+		.export_core		= crypto_sha256_export_core,
+		.import_core		= crypto_sha256_import_core,
+		.descsize		= sizeof(struct sha256_ctx),
+		.statesize		= SHA256_SHASH_STATE_SIZE,
+	},
+	{
+		.base.cra_name		= "hmac(sha224)",
+		.base.cra_driver_name	= "hmac-sha224-lib",
+		.base.cra_priority	= 300,
+		.base.cra_blocksize	= SHA224_BLOCK_SIZE,
+		.base.cra_ctxsize	= sizeof(struct hmac_sha224_key),
+		.base.cra_module	= THIS_MODULE,
+		.digestsize		= SHA224_DIGEST_SIZE,
+		.setkey			= crypto_hmac_sha224_setkey,
+		.init			= crypto_hmac_sha224_init,
+		.update			= crypto_hmac_sha224_update,
+		.final			= crypto_hmac_sha224_final,
+		.digest			= crypto_hmac_sha224_digest,
+		.export			= crypto_hmac_sha224_export,
+		.import			= crypto_hmac_sha224_import,
+		.export_core		= crypto_hmac_sha224_export_core,
+		.import_core		= crypto_hmac_sha224_import_core,
+		.descsize		= sizeof(struct hmac_sha224_ctx),
+		.statesize		= SHA256_SHASH_STATE_SIZE,
+	},
+	{
+		.base.cra_name		= "hmac(sha256)",
+		.base.cra_driver_name	= "hmac-sha256-lib",
+		.base.cra_priority	= 300,
+		.base.cra_blocksize	= SHA256_BLOCK_SIZE,
+		.base.cra_ctxsize	= sizeof(struct hmac_sha256_key),
+		.base.cra_module	= THIS_MODULE,
+		.digestsize		= SHA256_DIGEST_SIZE,
+		.setkey			= crypto_hmac_sha256_setkey,
+		.init			= crypto_hmac_sha256_init,
+		.update			= crypto_hmac_sha256_update,
+		.final			= crypto_hmac_sha256_final,
+		.digest			= crypto_hmac_sha256_digest,
+		.export			= crypto_hmac_sha256_export,
+		.import			= crypto_hmac_sha256_import,
+		.export_core		= crypto_hmac_sha256_export_core,
+		.import_core		= crypto_hmac_sha256_import_core,
+		.descsize		= sizeof(struct hmac_sha256_ctx),
+		.statesize		= SHA256_SHASH_STATE_SIZE,
+	},
+};
+
+static int __init crypto_sha256_mod_init(void)
+{
+	return crypto_register_shashes(algs, ARRAY_SIZE(algs));
+}
+module_init(crypto_sha256_mod_init);
+
+static void __exit crypto_sha256_mod_exit(void)
+{
+	crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
+}
+module_exit(crypto_sha256_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Crypto API support for SHA-224, SHA-256, HMAC-SHA224, and HMAC-SHA256");
+
+MODULE_ALIAS_CRYPTO("sha224");
+MODULE_ALIAS_CRYPTO("sha224-lib");
+MODULE_ALIAS_CRYPTO("sha256");
+MODULE_ALIAS_CRYPTO("sha256-lib");
+MODULE_ALIAS_CRYPTO("hmac(sha224)");
+MODULE_ALIAS_CRYPTO("hmac-sha224-lib");
+MODULE_ALIAS_CRYPTO("hmac(sha256)");
+MODULE_ALIAS_CRYPTO("hmac-sha256-lib");