Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (e0a0d058) · Commits · 戴 / test

Pull cpu hotplug fixes from Thomas Gleixner: "Two fixes for the hotplug state machine code: - Move the misplaces smb() in the hotplug thread function to the proper place, otherwise a half update control struct could be observed - Prevent state corruption on error rollback, which causes the state to advance by one and as a consequence skip it in the bringup sequence" * 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: cpu/hotplug: Prevent state corruption on error rollback cpu/hotplug: Adjust misplaced smb() in cpuhp_thread_fun()

kernel/cpu.c

+6 −5

Original line number	Diff line number	Diff line
		@@ -607,15 +607,15 @@ static void cpuhp_thread_fun(unsigned int cpu)
		bool bringup = st->bringup;
		enum cpuhp_state state;

		if (WARN_ON_ONCE(!st->should_run))
		return;

		/*
		* ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures
		* that if we see ->should_run we also see the rest of the state.
		*/
		smp_mb();

		if (WARN_ON_ONCE(!st->should_run))
		return;

		cpuhp_lock_acquire(bringup);

		if (st->single) {
		@@ -916,6 +916,7 @@ static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
		ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL);
		if (ret) {
		st->target = prev_state;
		if (st->state < prev_state)
		undo_cpu_down(cpu, st);
		break;
		}
		@@ -969,7 +970,7 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
		* to do the further cleanups.
		*/
		ret = cpuhp_down_callbacks(cpu, st, target);
		if (ret && st->state > CPUHP_TEARDOWN_CPU && st->state < prev_state) {
		if (ret && st->state == CPUHP_TEARDOWN_CPU && st->state < prev_state) {
		cpuhp_reset_state(st, prev_state);
		__cpuhp_kick_ap(st);
		}

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