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authorLinus Torvalds <torvalds@linux-foundation.org>2022-12-12 11:56:59 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2022-12-12 11:56:59 -0800
commit08d72bd299d08ae019a8a999b95f3e72643a11a4 (patch)
tree9f2753adef690aa528cadb32f83bf82f7c74e2ea /kernel
parent9d33edb20f7e6943250d6bb96ceaf2368f674d51 (diff)
parent6f855b39e4602b6b42a8e5cbcfefb8a1b8b5f0be (diff)
Merge tag 'smp-core-2022-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull CPU hotplug updates from Thomas Gleixner: "A small set of updates for CPU hotplug: - Prevent stale CPU hotplug state in the cpu_down() path which was detected by stress testing the sysfs interface - Ensure that the target CPU hotplug state for the boot CPU is CPUHP_ONLINE instead of the compile time init value CPUHP_OFFLINE. - Switch back to the original behaviour of warning when a CPU hotplug callback in the DYING/STARTING section returns an error code. Otherwise a buggy callback can leave the CPUs in an non recoverable state" * tag 'smp-core-2022-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: cpu/hotplug: Do not bail-out in DYING/STARTING sections cpu/hotplug: Set cpuhp target for boot cpu cpu/hotplug: Make target_store() a nop when target == state
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cpu.c61
1 files changed, 44 insertions, 17 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index bbad5e375d3b..6c0a92ca6bb5 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -663,21 +663,51 @@ static bool cpuhp_next_state(bool bringup,
return true;
}
-static int cpuhp_invoke_callback_range(bool bringup,
- unsigned int cpu,
- struct cpuhp_cpu_state *st,
- enum cpuhp_state target)
+static int __cpuhp_invoke_callback_range(bool bringup,
+ unsigned int cpu,
+ struct cpuhp_cpu_state *st,
+ enum cpuhp_state target,
+ bool nofail)
{
enum cpuhp_state state;
- int err = 0;
+ int ret = 0;
while (cpuhp_next_state(bringup, &state, st, target)) {
+ int err;
+
err = cpuhp_invoke_callback(cpu, state, bringup, NULL, NULL);
- if (err)
+ if (!err)
+ continue;
+
+ if (nofail) {
+ pr_warn("CPU %u %s state %s (%d) failed (%d)\n",
+ cpu, bringup ? "UP" : "DOWN",
+ cpuhp_get_step(st->state)->name,
+ st->state, err);
+ ret = -1;
+ } else {
+ ret = err;
break;
+ }
}
- return err;
+ return ret;
+}
+
+static inline int cpuhp_invoke_callback_range(bool bringup,
+ unsigned int cpu,
+ struct cpuhp_cpu_state *st,
+ enum cpuhp_state target)
+{
+ return __cpuhp_invoke_callback_range(bringup, cpu, st, target, false);
+}
+
+static inline void cpuhp_invoke_callback_range_nofail(bool bringup,
+ unsigned int cpu,
+ struct cpuhp_cpu_state *st,
+ enum cpuhp_state target)
+{
+ __cpuhp_invoke_callback_range(bringup, cpu, st, target, true);
}
static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st)
@@ -999,7 +1029,6 @@ static int take_cpu_down(void *_param)
struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE);
int err, cpu = smp_processor_id();
- int ret;
/* Ensure this CPU doesn't handle any more interrupts. */
err = __cpu_disable();
@@ -1012,13 +1041,10 @@ static int take_cpu_down(void *_param)
*/
WARN_ON(st->state != (CPUHP_TEARDOWN_CPU - 1));
- /* Invoke the former CPU_DYING callbacks */
- ret = cpuhp_invoke_callback_range(false, cpu, st, target);
-
/*
- * DYING must not fail!
+ * Invoke the former CPU_DYING callbacks. DYING must not fail!
*/
- WARN_ON_ONCE(ret);
+ cpuhp_invoke_callback_range_nofail(false, cpu, st, target);
/* Give up timekeeping duties */
tick_handover_do_timer();
@@ -1296,16 +1322,14 @@ void notify_cpu_starting(unsigned int cpu)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE);
- int ret;
rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */
cpumask_set_cpu(cpu, &cpus_booted_once_mask);
- ret = cpuhp_invoke_callback_range(true, cpu, st, target);
/*
* STARTING must not fail!
*/
- WARN_ON_ONCE(ret);
+ cpuhp_invoke_callback_range_nofail(true, cpu, st, target);
}
/*
@@ -2326,8 +2350,10 @@ static ssize_t target_store(struct device *dev, struct device_attribute *attr,
if (st->state < target)
ret = cpu_up(dev->id, target);
- else
+ else if (st->state > target)
ret = cpu_down(dev->id, target);
+ else if (WARN_ON(st->target != target))
+ st->target = target;
out:
unlock_device_hotplug();
return ret ? ret : count;
@@ -2688,6 +2714,7 @@ void __init boot_cpu_hotplug_init(void)
cpumask_set_cpu(smp_processor_id(), &cpus_booted_once_mask);
#endif
this_cpu_write(cpuhp_state.state, CPUHP_ONLINE);
+ this_cpu_write(cpuhp_state.target, CPUHP_ONLINE);
}
/*