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authorPeter Zijlstra <peterz@infradead.org>2017-09-20 19:00:20 +0200
committerThomas Gleixner <tglx@linutronix.de>2017-09-25 22:11:43 +0200
commit5f4b55e10645b7371322c800a5ec745cab487a6c (patch)
tree7075811470311ce6335c6b42b0e53a0b61722e5d /kernel/cpu.c
parent724a86881d03ee5794148e65142e24ed3621be66 (diff)
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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.c41
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);