diff options
| author | Paul Mackerras <paulus@samba.org> | 2009-12-15 19:40:32 +1100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-12-18 14:06:01 -0800 |
| commit | 517361c51d4a762531e669ebb2c081a1e678455a (patch) | |
| tree | 6241b5cad4ac5538939b7b7eae9208b9e01b3fdb | |
| parent | 60a48f8c19f1de13a99ad6d1972bbde8d193f3bd (diff) | |
| download | lwn-517361c51d4a762531e669ebb2c081a1e678455a.tar.gz lwn-517361c51d4a762531e669ebb2c081a1e678455a.zip | |
perf_event: Fix incorrect range check on cpu number
commit 0f624e7e5625f4c30c836b7a5decfe2553582391 upstream.
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>
LKML-Reference: <20091215084032.GA18661@brick.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | kernel/perf_event.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 61c35f583b90..6eee915a939e 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1583,7 +1583,7 @@ 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); /* |