Commit 4a298a43 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'smp-urgent-2025-12-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull CPU hotplug fix from Ingo Molnar:

 - Fix CPU hotplug callbacks to disable interrupts on UP kernels

* tag 'smp-urgent-2025-12-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  cpu: Make atomic hotplug callbacks run with interrupts disabled on UP
parents cba09e3e c9429191

kernel/cpu.c

+16 −9
Original line number Diff line number Diff line
@@ -249,6 +249,14 @@ static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, 
	return ret;

}



/*

 * The former STARTING/DYING states, ran with IRQs disabled and must not fail.

 */

static bool cpuhp_is_atomic_state(enum cpuhp_state state)

{

	return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE;

}



#ifdef CONFIG_SMP

static bool cpuhp_is_ap_state(enum cpuhp_state state)

{
@@ -271,14 +279,6 @@ static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup) 
	complete(done);

}



/*

 * The former STARTING/DYING states, ran with IRQs disabled and must not fail.

 */

static bool cpuhp_is_atomic_state(enum cpuhp_state state)

{

	return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE;

}



/* Synchronization state management */

enum cpuhp_sync_state {

	SYNC_STATE_DEAD,
@@ -2364,7 +2364,14 @@ static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, 
	else

		ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL);

#else

	if (cpuhp_is_atomic_state(state)) {

		guard(irqsave)();

		ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL);

		/* STARTING/DYING must not fail! */

		WARN_ON_ONCE(ret);

	} else {

		ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL);

	}

#endif

	BUG_ON(ret && !bringup);

	return ret;