powerpc/xive: Fix loop exit-condition in xive_find_target_in_mask()
xive_find_target_in_mask() has the following for(;;) loop which has a bug when @first == cpumask_first(@mask) and condition 1 fails to hold for every CPU in @mask. In this case we loop forever in the for-loop. first = cpu; for (;;) { if (cpu_online(cpu) && xive_try_pick_target(cpu)) // condition 1 return cpu; cpu = cpumask_next(cpu, mask); if (cpu == first) // condition 2 break; if (cpu >= nr_cpu_ids) // condition 3 cpu = cpumask_first(mask); } This is because, when @first == cpumask_first(@mask), we never hit the condition 2 (cpu == first) since prior to this check, we would have executed "cpu = cpumask_next(cpu, mask)" which will set the value of @cpu to a value greater than @first or to nr_cpus_ids. When this is coupled with the fact that condition 1 is not met, we will never exit this loop. This was discovered by the hard-lockup detector while running LTP test concurrently with SMT switch tests. w...
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03800e05
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