From 0d6526f82c3cdefcca47f73f5fc08dc6f335eac6 Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Mon, 21 Sep 2026 17:37:22 -0700 Subject: sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling bug 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 Suggested-by: Chen Yu Signed-off-by: Tim Chen Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Kayra Cizmeci Cc: # v7.2.x Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com --- crypto/kpp.c | 140 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 140 insertions(+) create mode 100644 crypto/kpp.c (limited to 'crypto/kpp.c') diff --git a/crypto/kpp.c b/crypto/kpp.c new file mode 100644 index 000000000..522c352a0 --- /dev/null +++ b/crypto/kpp.c @@ -0,0 +1,140 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Key-agreement Protocol Primitives (KPP) + * + * Copyright (c) 2016, Intel Corporation + * Authors: Salvatore Benedetto + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "internal.h" + +static int __maybe_unused crypto_kpp_report( + struct sk_buff *skb, struct crypto_alg *alg) +{ + struct crypto_report_kpp rkpp = { + .type = "kpp", + }; + + return nla_put(skb, CRYPTOCFGA_REPORT_KPP, sizeof(rkpp), &rkpp); +} + +static void __maybe_unused crypto_kpp_show(struct seq_file *m, + struct crypto_alg *alg) +{ + seq_puts(m, "type : kpp\n"); +} + +static void crypto_kpp_exit_tfm(struct crypto_tfm *tfm) +{ + struct crypto_kpp *kpp = __crypto_kpp_tfm(tfm); + struct kpp_alg *alg = crypto_kpp_alg(kpp); + + alg->exit(kpp); +} + +static int crypto_kpp_init_tfm(struct crypto_tfm *tfm) +{ + struct crypto_kpp *kpp = __crypto_kpp_tfm(tfm); + struct kpp_alg *alg = crypto_kpp_alg(kpp); + + if (alg->exit) + kpp->base.exit = crypto_kpp_exit_tfm; + + if (alg->init) + return alg->init(kpp); + + return 0; +} + +static void crypto_kpp_free_instance(struct crypto_instance *inst) +{ + struct kpp_instance *kpp = kpp_instance(inst); + + kpp->free(kpp); +} + +static const struct crypto_type crypto_kpp_type = { + .extsize = crypto_alg_extsize, + .init_tfm = crypto_kpp_init_tfm, + .free = crypto_kpp_free_instance, +#ifdef CONFIG_PROC_FS + .show = crypto_kpp_show, +#endif +#if IS_ENABLED(CONFIG_CRYPTO_USER) + .report = crypto_kpp_report, +#endif + .maskclear = ~CRYPTO_ALG_TYPE_MASK, + .maskset = CRYPTO_ALG_TYPE_MASK, + .type = CRYPTO_ALG_TYPE_KPP, + .tfmsize = offsetof(struct crypto_kpp, base), + .algsize = offsetof(struct kpp_alg, base), +}; + +struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask) +{ + return crypto_alloc_tfm(alg_name, &crypto_kpp_type, type, mask); +} +EXPORT_SYMBOL_GPL(crypto_alloc_kpp); + +int crypto_grab_kpp(struct crypto_kpp_spawn *spawn, + struct crypto_instance *inst, + const char *name, u32 type, u32 mask) +{ + spawn->base.frontend = &crypto_kpp_type; + return crypto_grab_spawn(&spawn->base, inst, name, type, mask); +} +EXPORT_SYMBOL_GPL(crypto_grab_kpp); + +int crypto_has_kpp(const char *alg_name, u32 type, u32 mask) +{ + return crypto_type_has_alg(alg_name, &crypto_kpp_type, type, mask); +} +EXPORT_SYMBOL_GPL(crypto_has_kpp); + +static void kpp_prepare_alg(struct kpp_alg *alg) +{ + struct crypto_alg *base = &alg->base; + + base->cra_type = &crypto_kpp_type; + base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK; + base->cra_flags |= CRYPTO_ALG_TYPE_KPP; +} + +int crypto_register_kpp(struct kpp_alg *alg) +{ + struct crypto_alg *base = &alg->base; + + kpp_prepare_alg(alg); + return crypto_register_alg(base); +} +EXPORT_SYMBOL_GPL(crypto_register_kpp); + +void crypto_unregister_kpp(struct kpp_alg *alg) +{ + crypto_unregister_alg(&alg->base); +} +EXPORT_SYMBOL_GPL(crypto_unregister_kpp); + +int kpp_register_instance(struct crypto_template *tmpl, + struct kpp_instance *inst) +{ + if (WARN_ON(!inst->free)) + return -EINVAL; + + kpp_prepare_alg(&inst->alg); + + return crypto_register_instance(tmpl, kpp_crypto_instance(inst)); +} +EXPORT_SYMBOL_GPL(kpp_register_instance); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Key-agreement Protocol Primitives"); -- cgit v1.3.1