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 --- net/netlabel/netlabel_user.c | 101 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 101 insertions(+) create mode 100644 net/netlabel/netlabel_user.c (limited to 'net/netlabel/netlabel_user.c') diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c new file mode 100644 index 000000000..0da652844 --- /dev/null +++ b/net/netlabel/netlabel_user.c @@ -0,0 +1,101 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * NetLabel NETLINK Interface + * + * This file defines the NETLINK interface for the NetLabel system. The + * NetLabel system manages static and dynamic label mappings for network + * protocols such as CIPSO and RIPSO. + * + * Author: Paul Moore + */ + +/* + * (c) Copyright Hewlett-Packard Development Company, L.P., 2006 + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "netlabel_mgmt.h" +#include "netlabel_unlabeled.h" +#include "netlabel_cipso_v4.h" +#include "netlabel_calipso.h" +#include "netlabel_user.h" + +/* + * NetLabel NETLINK Setup Functions + */ + +/** + * netlbl_netlink_init - Initialize the NETLINK communication channel + * + * Description: + * Call out to the NetLabel components so they can register their families and + * commands with the Generic NETLINK mechanism. Returns zero on success and + * non-zero on failure. + * + */ +int __init netlbl_netlink_init(void) +{ + int ret_val; + + ret_val = netlbl_mgmt_genl_init(); + if (ret_val != 0) + return ret_val; + + ret_val = netlbl_cipsov4_genl_init(); + if (ret_val != 0) + return ret_val; + + ret_val = netlbl_calipso_genl_init(); + if (ret_val != 0) + return ret_val; + + return netlbl_unlabel_genl_init(); +} + +/* + * NetLabel Audit Functions + */ + +/** + * netlbl_audit_start_common - Start an audit message + * @type: audit message type + * @audit_info: NetLabel audit information + * + * Description: + * Start an audit message using the type specified in @type and fill the audit + * message with some fields common to all NetLabel audit messages. Returns + * a pointer to the audit buffer on success, NULL on failure. + * + */ +struct audit_buffer *netlbl_audit_start_common(int type, + struct netlbl_audit *audit_info) +{ + struct audit_buffer *audit_buf; + + if (audit_enabled == AUDIT_OFF) + return NULL; + + audit_buf = audit_log_start(audit_context(), GFP_ATOMIC, type); + if (audit_buf == NULL) + return NULL; + + audit_log_format(audit_buf, "netlabel: auid=%u ses=%u", + from_kuid(&init_user_ns, audit_info->loginuid), + audit_info->sessionid); + audit_log_subj_ctx(audit_buf, &audit_info->prop); + + return audit_buf; +} -- cgit v1.3.1