diff options
author | Bibo Mao <maobibo@loongson.cn> | 2025-09-06 14:49:51 +0800 |
---|---|---|
committer | Thomas Gleixner <tglx@linutronix.de> | 2025-09-09 13:39:00 +0200 |
commit | fe2a449a45b13df1562419e0104b4777b6ea5248 (patch) | |
tree | f37875d3d9132b30ab521abeeb98fff852a6c15a | |
parent | 3c3af563b31766f67106c7549ad084a08ef613f2 (diff) |
tick: Do not set device to detached state in tick_shutdown()
tick_shutdown() sets the state of the clockevent device to detached
first and the invokes clockevents_exchange_device(), which in turn
invokes clockevents_switch_state().
But clockevents_switch_state() returns without invoking the device shutdown
callback as the device is already in detached state. As a consequence the
timer device is not shutdown when a CPU goes offline.
tick_shutdown() does this because it was originally invoked on a online CPU
and not on the outgoing CPU. It therefore could not access the clockevent
device of the already offlined CPU and just set the state.
Since commit 3b1596a21fbf tick_shutdown() is called on the outgoing CPU, so
the hardware device can be accessed.
Remove the state set before calling clockevents_exchange_device(), so that
the subsequent clockevents_switch_state() handles the state transition and
invokes the shutdown callback of the clockevent device.
[ tglx: Massaged change log ]
Fixes: 3b1596a21fbf ("clockevents: Shutdown and unregister current clockevents at CPUHP_AP_TICK_DYING")
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20250906064952.3749122-2-maobibo@loongson.cn
-rw-r--r-- | kernel/time/clockevents.c | 2 | ||||
-rw-r--r-- | kernel/time/tick-common.c | 16 | ||||
-rw-r--r-- | kernel/time/tick-internal.h | 2 |
3 files changed, 7 insertions, 13 deletions
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index f3e831f62906..a59bc75ab7c5 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -633,7 +633,7 @@ void tick_offline_cpu(unsigned int cpu) raw_spin_lock(&clockevents_lock); tick_broadcast_offline(cpu); - tick_shutdown(cpu); + tick_shutdown(); /* * Unregister the clock event devices which were diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index 9a3859443c04..7e33d3f2e889 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -411,24 +411,18 @@ int tick_cpu_dying(unsigned int dying_cpu) } /* - * Shutdown an event device on a given cpu: + * Shutdown an event device on the outgoing CPU: * - * This is called on a life CPU, when a CPU is dead. So we cannot - * access the hardware device itself. - * We just set the mode and remove it from the lists. + * Called by the dying CPU during teardown, with clockevents_lock held + * and interrupts disabled. */ -void tick_shutdown(unsigned int cpu) +void tick_shutdown(void) { - struct tick_device *td = &per_cpu(tick_cpu_device, cpu); + struct tick_device *td = this_cpu_ptr(&tick_cpu_device); struct clock_event_device *dev = td->evtdev; td->mode = TICKDEV_MODE_PERIODIC; if (dev) { - /* - * Prevent that the clock events layer tries to call - * the set mode function! - */ - clockevent_set_state(dev, CLOCK_EVT_STATE_DETACHED); clockevents_exchange_device(dev, NULL); dev->event_handler = clockevents_handle_noop; td->evtdev = NULL; diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h index faac36de35b9..4e4f7bbe2a64 100644 --- a/kernel/time/tick-internal.h +++ b/kernel/time/tick-internal.h @@ -26,7 +26,7 @@ extern void tick_setup_periodic(struct clock_event_device *dev, int broadcast); extern void tick_handle_periodic(struct clock_event_device *dev); extern void tick_check_new_device(struct clock_event_device *dev); extern void tick_offline_cpu(unsigned int cpu); -extern void tick_shutdown(unsigned int cpu); +extern void tick_shutdown(void); extern void tick_suspend(void); extern void tick_resume(void); extern bool tick_check_replacement(struct clock_event_device *curdev, |