From: Thomas Gleixner <tglx@linutronix.de> To: LKML <linux-kernel@vger.kernel.org> Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>, Steven Rostedt <rostedt@goodmis.org>, Sebastian Siewior <bigeasy@linutronix.de>, Paul McKenney <paulmck@linux.vnet.ibm.com> Subject: [patch V3 32/32] cpuhotplug: Link lock stacks for hotplug callbacks Date: Wed, 24 May 2017 10:15:43 +0200 Message-ID: <20170524081549.709375845@linutronix.de> (raw) In-Reply-To: <20170524081511.203800767@linutronix.de> [-- Attachment #0: cpuhotplug--Link-lock-stacks-for-hotplug-callbacks.patch --] [-- Type: text/plain, Size: 2290 bytes --] The CPU hotplug callbacks are not covered by lockdep versus the cpu hotplug rwsem. CPU0 CPU1 cpuhp_setup_state(STATE, startup, teardown); cpus_read_lock(); invoke_callback_on_ap(); kick_hotplug_thread(ap); wait_for_completion(); hotplug_thread_fn() lock(m); do_stuff(); unlock(m); Lockdep does not know about this dependency and will not trigger on the following code sequence: lock(m); cpus_read_lock(); Add a lockdep map and connect the initiators lock chain with the hotplug thread lock chain, so potential deadlocks can be detected. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- kernel/cpu.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -66,6 +66,12 @@ struct cpuhp_cpu_state { static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state); +#ifdef CONFIG_LOCKDEP +static struct lock_class_key cpuhp_state_key; +static struct lockdep_map cpuhp_state_lock_map = + STATIC_LOCKDEP_MAP_INIT("cpuhp_state", &cpuhp_state_key); +#endif + /** * cpuhp_step - Hotplug state machine step * @name: Name of the step @@ -403,6 +409,7 @@ static void cpuhp_thread_fun(unsigned in st->should_run = false; + lock_map_acquire(&cpuhp_state_lock_map); /* Single callback invocation for [un]install ? */ if (st->single) { if (st->cb_state < CPUHP_AP_ONLINE) { @@ -429,6 +436,7 @@ static void cpuhp_thread_fun(unsigned in else if (st->state > st->target) ret = cpuhp_ap_offline(cpu, st); } + lock_map_release(&cpuhp_state_lock_map); st->result = ret; complete(&st->done); } @@ -443,6 +451,9 @@ cpuhp_invoke_ap_callback(int cpu, enum c if (!cpu_online(cpu)) return 0; + lock_map_acquire(&cpuhp_state_lock_map); + lock_map_release(&cpuhp_state_lock_map); + /* * If we are up and running, use the hotplug thread. For early calls * we invoke the thread function directly. @@ -486,6 +497,8 @@ static int cpuhp_kick_ap_work(unsigned i enum cpuhp_state state = st->state; trace_cpuhp_enter(cpu, st->target, state, cpuhp_kick_ap_work); + lock_map_acquire(&cpuhp_state_lock_map); + lock_map_release(&cpuhp_state_lock_map); __cpuhp_kick_ap_work(st); wait_for_completion(&st->done); trace_cpuhp_exit(cpu, st->state, state, st->result);
next prev parent reply index Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-05-24 8:15 [patch V3 00/32] cpu/hotplug: Convert get_online_cpus() to a percpu_rwsem Thomas Gleixner 2017-05-24 8:15 ` [patch V3 01/32] cpu/hotplug: Provide cpus_read|write_[un]lock() Thomas Gleixner 2017-05-24 16:25 ` Paul E. McKenney 2017-05-26 8:31 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 02/32] cpu/hotplug: Provide lockdep_assert_cpus_held() Thomas Gleixner 2017-05-24 16:26 ` Paul E. McKenney 2017-05-26 8:32 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 03/32] cpu/hotplug: Provide cpuhp_setup/remove_state[_nocalls]_cpuslocked() Thomas Gleixner 2017-05-26 8:32 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior 2017-05-24 8:15 ` [patch V3 04/32] cpu/hotplug: Add __cpuhp_state_add_instance_cpuslocked() Thomas Gleixner 2017-05-26 8:33 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 05/32] stop_machine: Provide stop_machine_cpuslocked() Thomas Gleixner 2017-05-24 17:42 ` Paul E. McKenney 2017-05-26 8:33 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior 2017-05-24 8:15 ` [patch V3 06/32] padata: Make padata_alloc() static Thomas Gleixner 2017-05-26 8:34 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 07/32] padata: Avoid nested calls to cpus_read_lock() in pcrypt_init_padata() Thomas Gleixner 2017-05-26 8:35 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior 2017-05-24 8:15 ` [patch V3 08/32] x86/mtrr: Remove get_online_cpus() from mtrr_save_state() Thomas Gleixner 2017-05-26 8:35 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior 2017-05-24 8:15 ` [patch V3 09/32] cpufreq: Use cpuhp_setup_state_nocalls_cpuslocked() Thomas Gleixner 2017-05-26 8:36 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior 2017-05-24 8:15 ` [patch V3 10/32] KVM/PPC/Book3S HV: " Thomas Gleixner 2017-05-26 8:36 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior 2017-05-24 8:15 ` [patch V3 11/32] hwtracing/coresight-etm3x: " Thomas Gleixner 2017-05-25 16:46 ` Mathieu Poirier 2017-05-26 8:37 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior 2017-05-24 8:15 ` [patch V3 12/32] hwtracing/coresight-etm4x: " Thomas Gleixner 2017-05-25 16:47 ` Mathieu Poirier 2017-05-26 8:37 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior 2017-05-24 8:15 ` [patch V3 13/32] perf/x86/intel/cqm: Use cpuhp_setup_state_cpuslocked() Thomas Gleixner 2017-05-26 8:38 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior 2017-05-24 8:15 ` [patch V3 14/32] ARM/hw_breakpoint: " Thomas Gleixner 2017-05-26 8:38 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior 2017-05-24 8:15 ` [patch V3 15/32] s390/kernel: Use stop_machine_cpuslocked() Thomas Gleixner 2017-05-24 10:57 ` Heiko Carstens 2017-05-26 8:39 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior 2017-05-24 8:15 ` [patch V3 16/32] powerpc/powernv: " Thomas Gleixner 2017-05-26 8:40 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior 2017-05-24 8:15 ` [patch V3 17/32] cpu/hotplug: Use stop_machine_cpuslocked() in takedown_cpu() Thomas Gleixner 2017-05-26 8:40 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior 2017-05-24 8:15 ` [patch V3 18/32] x86/perf: Drop EXPORT of perf_check_microcode Thomas Gleixner 2017-05-26 8:41 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 19/32] perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode() Thomas Gleixner 2017-05-26 8:41 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior 2017-05-24 8:15 ` [patch V3 20/32] PCI: Use cpu_hotplug_disable() instead of get_online_cpus() Thomas Gleixner 2017-05-26 8:42 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 21/32] PCI: Replace the racy recursion prevention Thomas Gleixner 2017-05-26 8:42 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 22/32] ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus() Thomas Gleixner 2017-05-26 8:43 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 23/32] perf/tracing/cpuhotplug: Fix locking order Thomas Gleixner 2017-05-24 18:30 ` Paul E. McKenney 2017-05-24 18:47 ` Thomas Gleixner 2017-05-24 21:10 ` Paul E. McKenney 2017-05-30 11:22 ` Peter Zijlstra 2017-05-30 16:25 ` Paul E. McKenney 2017-05-26 8:43 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 24/32] jump_label: Reorder hotplug lock and jump_label_lock Thomas Gleixner 2017-05-24 12:50 ` David Miller 2017-05-26 8:44 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 25/32] kprobes: Cure hotplug lock ordering issues Thomas Gleixner 2017-05-24 15:54 ` Masami Hiramatsu 2017-05-26 7:47 ` Thomas Gleixner 2017-05-26 8:45 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 26/32] arm64: Prevent cpu hotplug rwsem recursion Thomas Gleixner 2017-05-26 8:45 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 27/32] arm: Prevent " Thomas Gleixner 2017-05-26 8:46 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 28/32] s390: " Thomas Gleixner 2017-05-24 10:57 ` Heiko Carstens 2017-05-26 8:46 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 29/32] cpu/hotplug: Convert hotplug locking to percpu rwsem Thomas Gleixner 2017-05-26 8:47 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 30/32] sched: Provide is_percpu_thread() helper Thomas Gleixner 2017-05-26 8:47 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` [patch V3 31/32] acpi/processor: Prevent cpu hotplug deadlock Thomas Gleixner 2017-05-26 8:48 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner 2017-05-24 8:15 ` Thomas Gleixner [this message] 2017-05-26 8:48 ` [tip:smp/hotplug] cpuhotplug: Link lock stacks for hotplug callbacks tip-bot for Thomas Gleixner 2017-05-24 16:22 ` [patch V3 00/32] cpu/hotplug: Convert get_online_cpus() to a percpu_rwsem Paul E. McKenney 2017-05-26 7:03 ` Ingo Molnar
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