perf_event: Fix incorrect range check on cpu number
It is quite legitimate for CPUs to be numbered sparsely, meaning that it possible for an online CPU to have a number which is greater than the total count of possible CPUs. Currently find_get_context() has a sanity check on the cpu number where it checks it against num_possible_cpus(). This test can fail for a legitimate cpu number if the cpu_possible_mask is sparsely populated. This fixes the problem by checking the CPU number against nr_cpumask_bits instead, since that is the appropriate check to ensure that the cpu number is same to pass to cpu_isset() subsequently. Reported-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Tested-by: Michael Neuling <mikey@neuling.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: <stable@kernel.org> LKML-Reference: <20091215084032.GA18661@brick.ozlabs.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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