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Message-Id: <20091217035702.439056851@mini.kroah.org>
Date: Wed, 16 Dec 2009 19:57:27 -0800
From: Greg KH <gregkh@...e.de>
To: linux-kernel@...r.kernel.org, stable@...nel.org
Cc: stable-review@...nel.org, torvalds@...ux-foundation.org,
akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
Paul Mackerras <paulus@...ba.org>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...e.hu>
Subject: [150/151] perf_event: Fix incorrect range check on cpu number
2.6.32-stable review patch. If anyone has any objections, please let us know.
------------------
From: Paul Mackerras <paulus@...ba.org>
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@...ling.org>
Signed-off-by: Paul Mackerras <paulus@...ba.org>
Tested-by: Michael Neuling <mikey@...ling.org>
Acked-by: Peter Zijlstra <peterz@...radead.org>
LKML-Reference: <20091215084032.GA18661@...ck.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>
---
kernel/perf_event.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -1583,7 +1583,7 @@ static struct perf_event_context *find_g
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);
/*
--
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