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, 425 insertions, 0 deletions

diff --git a/crypto/sha512.c b/crypto/sha512.c
new file mode 100644
index 000000000..d320fe539
--- /dev/null
+++ b/crypto/sha512.c
@@ -0,0 +1,425 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Crypto API support for SHA-384, SHA-512, HMAC-SHA384, and HMAC-SHA512
+ *
+ * Copyright (c) Jean-Luc Cooke <jlcooke@certainkey.com>
+ * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
+ * Copyright (c) 2003 Kyle McMartin <kyle@debian.org>
+ * 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_lo must be block-aligned
+ * and the remainder must be stored in an extra u8 appended to the struct.
+ */
+
+#define SHA512_SHASH_STATE_SIZE 209
+static_assert(offsetof(struct __sha512_ctx, state) == 0);
+static_assert(offsetof(struct __sha512_ctx, bytecount_lo) == 64);
+static_assert(offsetof(struct __sha512_ctx, bytecount_hi) == 72);
+static_assert(offsetof(struct __sha512_ctx, buf) == 80);
+static_assert(sizeof(struct __sha512_ctx) + 1 == SHA512_SHASH_STATE_SIZE);
+
+static int __crypto_sha512_export(const struct __sha512_ctx *ctx0, void *out)
+{
+	struct __sha512_ctx ctx = *ctx0;
+	unsigned int partial;
+	u8 *p = out;
+
+	partial = ctx.bytecount_lo % SHA512_BLOCK_SIZE;
+	ctx.bytecount_lo -= partial;
+	memcpy(p, &ctx, sizeof(ctx));
+	p += sizeof(ctx);
+	*p = partial;
+	return 0;
+}
+
+static int __crypto_sha512_import(struct __sha512_ctx *ctx, const void *in)
+{
+	const u8 *p = in;
+
+	memcpy(ctx, p, sizeof(*ctx));
+	p += sizeof(*ctx);
+	ctx->bytecount_lo += *p;
+	return 0;
+}
+
+static int __crypto_sha512_export_core(const struct __sha512_ctx *ctx,
+				       void *out)
+{
+	memcpy(out, ctx, offsetof(struct __sha512_ctx, buf));
+	return 0;
+}
+
+static int __crypto_sha512_import_core(struct __sha512_ctx *ctx, const void *in)
+{
+	memcpy(ctx, in, offsetof(struct __sha512_ctx, buf));
+	return 0;
+}
+
+/* SHA-384 */
+
+const u8 sha384_zero_message_hash[SHA384_DIGEST_SIZE] = {
+	0x38, 0xb0, 0x60, 0xa7, 0x51, 0xac, 0x96, 0x38,
+	0x4c, 0xd9, 0x32, 0x7e, 0xb1, 0xb1, 0xe3, 0x6a,
+	0x21, 0xfd, 0xb7, 0x11, 0x14, 0xbe, 0x07, 0x43,
+	0x4c, 0x0c, 0xc7, 0xbf, 0x63, 0xf6, 0xe1, 0xda,
+	0x27, 0x4e, 0xde, 0xbf, 0xe7, 0x6f, 0x65, 0xfb,
+	0xd5, 0x1a, 0xd2, 0xf1, 0x48, 0x98, 0xb9, 0x5b
+};
+EXPORT_SYMBOL_GPL(sha384_zero_message_hash);
+
+#define SHA384_CTX(desc) ((struct sha384_ctx *)shash_desc_ctx(desc))
+
+static int crypto_sha384_init(struct shash_desc *desc)
+{
+	sha384_init(SHA384_CTX(desc));
+	return 0;
+}
+
+static int crypto_sha384_update(struct shash_desc *desc,
+				const u8 *data, unsigned int len)
+{
+	sha384_update(SHA384_CTX(desc), data, len);
+	return 0;
+}
+
+static int crypto_sha384_final(struct shash_desc *desc, u8 *out)
+{
+	sha384_final(SHA384_CTX(desc), out);
+	return 0;
+}
+
+static int crypto_sha384_digest(struct shash_desc *desc,
+				const u8 *data, unsigned int len, u8 *out)
+{
+	sha384(data, len, out);
+	return 0;
+}
+
+static int crypto_sha384_export(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha512_export(&SHA384_CTX(desc)->ctx, out);
+}
+
+static int crypto_sha384_import(struct shash_desc *desc, const void *in)
+{
+	return __crypto_sha512_import(&SHA384_CTX(desc)->ctx, in);
+}
+
+static int crypto_sha384_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha512_export_core(&SHA384_CTX(desc)->ctx, out);
+}
+
+static int crypto_sha384_import_core(struct shash_desc *desc, const void *in)
+{
+	return __crypto_sha512_import_core(&SHA384_CTX(desc)->ctx, in);
+}
+
+/* SHA-512 */
+
+const u8 sha512_zero_message_hash[SHA512_DIGEST_SIZE] = {
+	0xcf, 0x83, 0xe1, 0x35, 0x7e, 0xef, 0xb8, 0xbd,
+	0xf1, 0x54, 0x28, 0x50, 0xd6, 0x6d, 0x80, 0x07,
+	0xd6, 0x20, 0xe4, 0x05, 0x0b, 0x57, 0x15, 0xdc,
+	0x83, 0xf4, 0xa9, 0x21, 0xd3, 0x6c, 0xe9, 0xce,
+	0x47, 0xd0, 0xd1, 0x3c, 0x5d, 0x85, 0xf2, 0xb0,
+	0xff, 0x83, 0x18, 0xd2, 0x87, 0x7e, 0xec, 0x2f,
+	0x63, 0xb9, 0x31, 0xbd, 0x47, 0x41, 0x7a, 0x81,
+	0xa5, 0x38, 0x32, 0x7a, 0xf9, 0x27, 0xda, 0x3e
+};
+EXPORT_SYMBOL_GPL(sha512_zero_message_hash);
+
+#define SHA512_CTX(desc) ((struct sha512_ctx *)shash_desc_ctx(desc))
+
+static int crypto_sha512_init(struct shash_desc *desc)
+{
+	sha512_init(SHA512_CTX(desc));
+	return 0;
+}
+
+static int crypto_sha512_update(struct shash_desc *desc,
+				const u8 *data, unsigned int len)
+{
+	sha512_update(SHA512_CTX(desc), data, len);
+	return 0;
+}
+
+static int crypto_sha512_final(struct shash_desc *desc, u8 *out)
+{
+	sha512_final(SHA512_CTX(desc), out);
+	return 0;
+}
+
+static int crypto_sha512_digest(struct shash_desc *desc,
+				const u8 *data, unsigned int len, u8 *out)
+{
+	sha512(data, len, out);
+	return 0;
+}
+
+static int crypto_sha512_export(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha512_export(&SHA512_CTX(desc)->ctx, out);
+}
+
+static int crypto_sha512_import(struct shash_desc *desc, const void *in)
+{
+	return __crypto_sha512_import(&SHA512_CTX(desc)->ctx, in);
+}
+
+static int crypto_sha512_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha512_export_core(&SHA512_CTX(desc)->ctx, out);
+}
+
+static int crypto_sha512_import_core(struct shash_desc *desc, const void *in)
+{
+	return __crypto_sha512_import_core(&SHA512_CTX(desc)->ctx, in);
+}
+
+/* HMAC-SHA384 */
+
+#define HMAC_SHA384_KEY(tfm) ((struct hmac_sha384_key *)crypto_shash_ctx(tfm))
+#define HMAC_SHA384_CTX(desc) ((struct hmac_sha384_ctx *)shash_desc_ctx(desc))
+
+static int crypto_hmac_sha384_setkey(struct crypto_shash *tfm,
+				     const u8 *raw_key, unsigned int keylen)
+{
+	hmac_sha384_preparekey(HMAC_SHA384_KEY(tfm), raw_key, keylen);
+	return 0;
+}
+
+static int crypto_hmac_sha384_init(struct shash_desc *desc)
+{
+	hmac_sha384_init(HMAC_SHA384_CTX(desc), HMAC_SHA384_KEY(desc->tfm));
+	return 0;
+}
+
+static int crypto_hmac_sha384_update(struct shash_desc *desc,
+				     const u8 *data, unsigned int len)
+{
+	hmac_sha384_update(HMAC_SHA384_CTX(desc), data, len);
+	return 0;
+}
+
+static int crypto_hmac_sha384_final(struct shash_desc *desc, u8 *out)
+{
+	hmac_sha384_final(HMAC_SHA384_CTX(desc), out);
+	return 0;
+}
+
+static int crypto_hmac_sha384_digest(struct shash_desc *desc,
+				     const u8 *data, unsigned int len,
+				     u8 *out)
+{
+	hmac_sha384(HMAC_SHA384_KEY(desc->tfm), data, len, out);
+	return 0;
+}
+
+static int crypto_hmac_sha384_export(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha512_export(&HMAC_SHA384_CTX(desc)->ctx.sha_ctx, out);
+}
+
+static int crypto_hmac_sha384_import(struct shash_desc *desc, const void *in)
+{
+	struct hmac_sha384_ctx *ctx = HMAC_SHA384_CTX(desc);
+
+	ctx->ctx.ostate = HMAC_SHA384_KEY(desc->tfm)->key.ostate;
+	return __crypto_sha512_import(&ctx->ctx.sha_ctx, in);
+}
+
+static int crypto_hmac_sha384_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha512_export_core(&HMAC_SHA384_CTX(desc)->ctx.sha_ctx,
+					   out);
+}
+
+static int crypto_hmac_sha384_import_core(struct shash_desc *desc,
+					  const void *in)
+{
+	struct hmac_sha384_ctx *ctx = HMAC_SHA384_CTX(desc);
+
+	ctx->ctx.ostate = HMAC_SHA384_KEY(desc->tfm)->key.ostate;
+	return __crypto_sha512_import_core(&ctx->ctx.sha_ctx, in);
+}
+
+/* HMAC-SHA512 */
+
+#define HMAC_SHA512_KEY(tfm) ((struct hmac_sha512_key *)crypto_shash_ctx(tfm))
+#define HMAC_SHA512_CTX(desc) ((struct hmac_sha512_ctx *)shash_desc_ctx(desc))
+
+static int crypto_hmac_sha512_setkey(struct crypto_shash *tfm,
+				     const u8 *raw_key, unsigned int keylen)
+{
+	hmac_sha512_preparekey(HMAC_SHA512_KEY(tfm), raw_key, keylen);
+	return 0;
+}
+
+static int crypto_hmac_sha512_init(struct shash_desc *desc)
+{
+	hmac_sha512_init(HMAC_SHA512_CTX(desc), HMAC_SHA512_KEY(desc->tfm));
+	return 0;
+}
+
+static int crypto_hmac_sha512_update(struct shash_desc *desc,
+				     const u8 *data, unsigned int len)
+{
+	hmac_sha512_update(HMAC_SHA512_CTX(desc), data, len);
+	return 0;
+}
+
+static int crypto_hmac_sha512_final(struct shash_desc *desc, u8 *out)
+{
+	hmac_sha512_final(HMAC_SHA512_CTX(desc), out);
+	return 0;
+}
+
+static int crypto_hmac_sha512_digest(struct shash_desc *desc,
+				     const u8 *data, unsigned int len,
+				     u8 *out)
+{
+	hmac_sha512(HMAC_SHA512_KEY(desc->tfm), data, len, out);
+	return 0;
+}
+
+static int crypto_hmac_sha512_export(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha512_export(&HMAC_SHA512_CTX(desc)->ctx.sha_ctx, out);
+}
+
+static int crypto_hmac_sha512_import(struct shash_desc *desc, const void *in)
+{
+	struct hmac_sha512_ctx *ctx = HMAC_SHA512_CTX(desc);
+
+	ctx->ctx.ostate = HMAC_SHA512_KEY(desc->tfm)->key.ostate;
+	return __crypto_sha512_import(&ctx->ctx.sha_ctx, in);
+}
+
+static int crypto_hmac_sha512_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha512_export_core(&HMAC_SHA512_CTX(desc)->ctx.sha_ctx,
+					   out);
+}
+
+static int crypto_hmac_sha512_import_core(struct shash_desc *desc,
+					  const void *in)
+{
+	struct hmac_sha512_ctx *ctx = HMAC_SHA512_CTX(desc);
+
+	ctx->ctx.ostate = HMAC_SHA512_KEY(desc->tfm)->key.ostate;
+	return __crypto_sha512_import_core(&ctx->ctx.sha_ctx, in);
+}
+
+/* Algorithm definitions */
+
+static struct shash_alg algs[] = {
+	{
+		.base.cra_name		= "sha384",
+		.base.cra_driver_name	= "sha384-lib",
+		.base.cra_priority	= 300,
+		.base.cra_blocksize	= SHA384_BLOCK_SIZE,
+		.base.cra_module	= THIS_MODULE,
+		.digestsize		= SHA384_DIGEST_SIZE,
+		.init			= crypto_sha384_init,
+		.update			= crypto_sha384_update,
+		.final			= crypto_sha384_final,
+		.digest			= crypto_sha384_digest,
+		.export			= crypto_sha384_export,
+		.import			= crypto_sha384_import,
+		.export_core		= crypto_sha384_export_core,
+		.import_core		= crypto_sha384_import_core,
+		.descsize		= sizeof(struct sha384_ctx),
+		.statesize		= SHA512_SHASH_STATE_SIZE,
+	},
+	{
+		.base.cra_name		= "sha512",
+		.base.cra_driver_name	= "sha512-lib",
+		.base.cra_priority	= 300,
+		.base.cra_blocksize	= SHA512_BLOCK_SIZE,
+		.base.cra_module	= THIS_MODULE,
+		.digestsize		= SHA512_DIGEST_SIZE,
+		.init			= crypto_sha512_init,
+		.update			= crypto_sha512_update,
+		.final			= crypto_sha512_final,
+		.digest			= crypto_sha512_digest,
+		.export			= crypto_sha512_export,
+		.import			= crypto_sha512_import,
+		.export_core		= crypto_sha512_export_core,
+		.import_core		= crypto_sha512_import_core,
+		.descsize		= sizeof(struct sha512_ctx),
+		.statesize		= SHA512_SHASH_STATE_SIZE,
+	},
+	{
+		.base.cra_name		= "hmac(sha384)",
+		.base.cra_driver_name	= "hmac-sha384-lib",
+		.base.cra_priority	= 300,
+		.base.cra_blocksize	= SHA384_BLOCK_SIZE,
+		.base.cra_ctxsize	= sizeof(struct hmac_sha384_key),
+		.base.cra_module	= THIS_MODULE,
+		.digestsize		= SHA384_DIGEST_SIZE,
+		.setkey			= crypto_hmac_sha384_setkey,
+		.init			= crypto_hmac_sha384_init,
+		.update			= crypto_hmac_sha384_update,
+		.final			= crypto_hmac_sha384_final,
+		.digest			= crypto_hmac_sha384_digest,
+		.export			= crypto_hmac_sha384_export,
+		.import			= crypto_hmac_sha384_import,
+		.export_core		= crypto_hmac_sha384_export_core,
+		.import_core		= crypto_hmac_sha384_import_core,
+		.descsize		= sizeof(struct hmac_sha384_ctx),
+		.statesize		= SHA512_SHASH_STATE_SIZE,
+	},
+	{
+		.base.cra_name		= "hmac(sha512)",
+		.base.cra_driver_name	= "hmac-sha512-lib",
+		.base.cra_priority	= 300,
+		.base.cra_blocksize	= SHA512_BLOCK_SIZE,
+		.base.cra_ctxsize	= sizeof(struct hmac_sha512_key),
+		.base.cra_module	= THIS_MODULE,
+		.digestsize		= SHA512_DIGEST_SIZE,
+		.setkey			= crypto_hmac_sha512_setkey,
+		.init			= crypto_hmac_sha512_init,
+		.update			= crypto_hmac_sha512_update,
+		.final			= crypto_hmac_sha512_final,
+		.digest			= crypto_hmac_sha512_digest,
+		.export			= crypto_hmac_sha512_export,
+		.import			= crypto_hmac_sha512_import,
+		.export_core		= crypto_hmac_sha512_export_core,
+		.import_core		= crypto_hmac_sha512_import_core,
+		.descsize		= sizeof(struct hmac_sha512_ctx),
+		.statesize		= SHA512_SHASH_STATE_SIZE,
+	},
+};
+
+static int __init crypto_sha512_mod_init(void)
+{
+	return crypto_register_shashes(algs, ARRAY_SIZE(algs));
+}
+module_init(crypto_sha512_mod_init);
+
+static void __exit crypto_sha512_mod_exit(void)
+{
+	crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
+}
+module_exit(crypto_sha512_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Crypto API support for SHA-384, SHA-512, HMAC-SHA384, and HMAC-SHA512");
+
+MODULE_ALIAS_CRYPTO("sha384");
+MODULE_ALIAS_CRYPTO("sha384-lib");
+MODULE_ALIAS_CRYPTO("sha512");
+MODULE_ALIAS_CRYPTO("sha512-lib");
+MODULE_ALIAS_CRYPTO("hmac(sha384)");
+MODULE_ALIAS_CRYPTO("hmac-sha384-lib");
+MODULE_ALIAS_CRYPTO("hmac(sha512)");
+MODULE_ALIAS_CRYPTO("hmac-sha512-lib");