diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2017-09-20 19:00:20 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-09-25 22:11:43 +0200 |
| commit | 5f4b55e10645b7371322c800a5ec745cab487a6c (patch) | |
| tree | 7075811470311ce6335c6b42b0e53a0b61722e5d /kernel/cpu.c | |
| parent | 724a86881d03ee5794148e65142e24ed3621be66 (diff) | |
smp/hotplug: Differentiate the AP-work lockdep class between up and down
With lockdep-crossrelease we get deadlock reports that span cpu-up and
cpu-down chains. Such deadlocks cannot possibly happen because cpu-up
and cpu-down are globally serialized.
CPU0 CPU1 CPU2
cpuhp_up_callbacks: takedown_cpu: cpuhp_thread_fun:
cpuhp_state
irq_lock_sparse()
irq_lock_sparse()
wait_for_completion()
cpuhp_state
complete()
Now that we have consistent AP state, we can trivially separate the
AP-work class between up and down using st->bringup.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: max.byungchul.park@gmail.com
Cc: bigeasy@linutronix.de
Cc: efault@gmx.de
Cc: rostedt@goodmis.org
Link: https://lkml.kernel.org/r/20170920170546.922524234@infradead.org
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 41 |
1 files changed, 32 insertions, 9 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index d6f1b8c36400..d5c09985fbb6 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -68,9 +68,26 @@ struct cpuhp_cpu_state { static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state); #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP) -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); +static struct lockdep_map cpuhp_state_up_map = + STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map); +static struct lockdep_map cpuhp_state_down_map = + STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map); + + +static void inline cpuhp_lock_acquire(bool bringup) +{ + lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); +} + +static void inline cpuhp_lock_release(bool bringup) +{ + lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); +} +#else + +static void inline cpuhp_lock_acquire(bool bringup) { } +static void inline cpuhp_lock_release(bool bringup) { } + #endif /** @@ -486,7 +503,7 @@ static void cpuhp_thread_fun(unsigned int cpu) if (WARN_ON_ONCE(!st->should_run)) return; - lock_map_acquire(&cpuhp_state_lock_map); + cpuhp_lock_acquire(bringup); if (st->single) { state = st->cb_state; @@ -537,7 +554,7 @@ static void cpuhp_thread_fun(unsigned int cpu) } next: - lock_map_release(&cpuhp_state_lock_map); + cpuhp_lock_release(bringup); if (!st->should_run) complete(&st->done); @@ -554,8 +571,11 @@ cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, if (!cpu_online(cpu)) return 0; - lock_map_acquire(&cpuhp_state_lock_map); - lock_map_release(&cpuhp_state_lock_map); + cpuhp_lock_acquire(false); + cpuhp_lock_release(false); + + cpuhp_lock_acquire(true); + cpuhp_lock_release(true); /* * If we are up and running, use the hotplug thread. For early calls @@ -593,8 +613,11 @@ static int cpuhp_kick_ap_work(unsigned int cpu) enum cpuhp_state prev_state = st->state; int ret; - lock_map_acquire(&cpuhp_state_lock_map); - lock_map_release(&cpuhp_state_lock_map); + cpuhp_lock_acquire(false); + cpuhp_lock_release(false); + + cpuhp_lock_acquire(true); + cpuhp_lock_release(true); trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work); ret = cpuhp_kick_ap(st, st->target); |