Messages in this thread Patch in this message | | | From | Qian Cai <> | Subject | [PATCH v2] x86/resctrl: fix an imbalance in domain_remove_cpu | Date | Tue, 10 Dec 2019 22:30:42 -0500 |
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A system that supports resource monitoring may have multiple resources while not all of these resources are capable of monitoring. Monitoring related state is initialized only for resources that are capable of monitoring and correspondingly this state should subsequently only be removed from these resources that are capable of monitoring.
domain_add_cpu() calls domain_setup_mon_state() only when r->mon_capable is true where it will initialize d->mbm_over. However, domain_remove_cpu() calls cancel_delayed_work(&d->mbm_over) without checking r->mon_capable resulting in an attempt to cancel d->mbm_over on all resources, even those that never initialized d->mbm_over because they are not capable of monitoring. Hence, it triggers a debugobjects warning when offlining CPUs because those timer debugobjects are never initialized.
ODEBUG: assert_init not available (active state 0) object type: timer_list hint: 0x0 WARNING: CPU: 143 PID: 789 at lib/debugobjects.c:484 debug_print_object+0xfe/0x140 Hardware name: HP Synergy 680 Gen9/Synergy 680 Gen9 Compute Module, BIOS I40 05/23/2018 RIP: 0010:debug_print_object+0xfe/0x140 Call Trace: debug_object_assert_init+0x1f5/0x240 del_timer+0x6f/0xf0 try_to_grab_pending+0x42/0x3c0 cancel_delayed_work+0x7d/0x150 resctrl_offline_cpu+0x3c0/0x520 cpuhp_invoke_callback+0x197/0x1120 cpuhp_thread_fun+0x252/0x2f0 smpboot_thread_fn+0x255/0x440 kthread+0x1e6/0x210 ret_from_fork+0x3a/0x50
Fixes: e33026831bdb ("x86/intel_rdt/mbm: Handle counter overflow") Signed-off-by: Qian Cai <cai@lca.pw> ---
v2: update the commit log thanks to Reinette.
arch/x86/kernel/cpu/resctrl/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c index 03eb90d00af0..89049b343c7a 100644 --- a/arch/x86/kernel/cpu/resctrl/core.c +++ b/arch/x86/kernel/cpu/resctrl/core.c @@ -618,7 +618,7 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r) if (static_branch_unlikely(&rdt_mon_enable_key)) rmdir_mondata_subdir_allrdtgrp(r, d->id); list_del(&d->list); - if (is_mbm_enabled()) + if (r->mon_capable && is_mbm_enabled()) cancel_delayed_work(&d->mbm_over); if (is_llc_occupancy_enabled() && has_busy_rmid(r, d)) { /* -- 2.21.0 (Apple Git-122.2)
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