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/fips.c | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 crypto/fips.c (limited to 'crypto/fips.c') diff --git a/crypto/fips.c b/crypto/fips.c new file mode 100644 index 000000000..c59711248 --- /dev/null +++ b/crypto/fips.c @@ -0,0 +1,102 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * FIPS 200 support. + * + * Copyright (c) 2008 Neil Horman + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +int fips_enabled; +EXPORT_SYMBOL_GPL(fips_enabled); + +ATOMIC_NOTIFIER_HEAD(fips_fail_notif_chain); +EXPORT_SYMBOL_GPL(fips_fail_notif_chain); + +/* Process kernel command-line parameter at boot time. fips=0 or fips=1 */ +static int __init fips_enable(char *str) +{ + if (kstrtoint(str, 0, &fips_enabled)) + return 0; + + fips_enabled = !!fips_enabled; + pr_info("fips mode: %s\n", str_enabled_disabled(fips_enabled)); + return 1; +} + +__setup("fips=", fips_enable); + +#define FIPS_MODULE_NAME CONFIG_CRYPTO_FIPS_NAME +#ifdef CONFIG_CRYPTO_FIPS_CUSTOM_VERSION +#define FIPS_MODULE_VERSION CONFIG_CRYPTO_FIPS_VERSION +#else +#define FIPS_MODULE_VERSION UTS_RELEASE +#endif + +static char fips_name[] = FIPS_MODULE_NAME; +static char fips_version[] = FIPS_MODULE_VERSION; + +static const struct ctl_table crypto_sysctl_table[] = { + { + .procname = "fips_enabled", + .data = &fips_enabled, + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = proc_dointvec + }, + { + .procname = "fips_name", + .data = &fips_name, + .maxlen = 64, + .mode = 0444, + .proc_handler = proc_dostring + }, + { + .procname = "fips_version", + .data = &fips_version, + .maxlen = 64, + .mode = 0444, + .proc_handler = proc_dostring + }, +}; + +static struct ctl_table_header *crypto_sysctls; + +static void crypto_proc_fips_init(void) +{ + crypto_sysctls = register_sysctl("crypto", crypto_sysctl_table); +} + +static void crypto_proc_fips_exit(void) +{ + unregister_sysctl_table(crypto_sysctls); +} + +void fips_fail_notify(void) +{ + if (fips_enabled) + atomic_notifier_call_chain(&fips_fail_notif_chain, 0, NULL); +} +EXPORT_SYMBOL_GPL(fips_fail_notify); + +static int __init fips_init(void) +{ + crypto_proc_fips_init(); + return 0; +} + +static void __exit fips_exit(void) +{ + crypto_proc_fips_exit(); +} + +module_init(fips_init); +module_exit(fips_exit); -- cgit v1.3.1