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authorPaul Mackerras <paulus@samba.org>2009-12-15 19:40:32 +1100
committerIngo Molnar <mingo@elte.hu>2009-12-15 13:09:55 +0100
commit0f624e7e5625f4c30c836b7a5decfe2553582391 (patch)
tree6de6f9fbb15db70007238c923efb48dcde194c20
parenta6005123ce22770dbd91bc3cb637ce0807ab959b (diff)
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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>
-rw-r--r--kernel/perf_event.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index d891ec4..8823b08 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -1603,7 +1603,7 @@ static struct perf_event_context *find_get_context(pid_t pid, int cpu)
if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
return ERR_PTR(-EACCES);
- if (cpu < 0 || cpu > num_possible_cpus())
+ if (cpu < 0 || cpu >= nr_cpumask_bits)
return ERR_PTR(-EINVAL);
/*