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author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-12 22:56:59 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-12 22:56:59 +0300 |
commit | 08d72bd299d08ae019a8a999b95f3e72643a11a4 (patch) | |
tree | 9f2753adef690aa528cadb32f83bf82f7c74e2ea | |
parent | 9d33edb20f7e6943250d6bb96ceaf2368f674d51 (diff) | |
parent | 6f855b39e4602b6b42a8e5cbcfefb8a1b8b5f0be (diff) | |
download | linux-08d72bd299d08ae019a8a999b95f3e72643a11a4.tar.xz |
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
-rw-r--r-- | kernel/cpu.c | 61 |
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); } /* |