| Date | Tue, 15 Feb 2011 16:14:21 -0800 | From | Greg KH <> | Subject | [204/272] perf: Fix alloc_callchain_buffers() |
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2.6.37-stable review patch. If anyone has any objections, please let us know.
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From: Eric Dumazet <eric.dumazet@gmail.com>
commit 88d4f0db7fa8785859c1d637f9aac210932b6216 upstream.
Commit 927c7a9e92c4 ("perf: Fix race in callchains") introduced a mismatch in the sizing of struct callchain_cpus_entries.
nr_cpu_ids must be used instead of num_possible_cpus(), or we might get out of bound memory accesses on some machines.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Miller <davem@davemloft.net> Cc: Stephane Eranian <eranian@google.com> LKML-Reference: <1295980851.3588.351.camel@edumazet-laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- kernel/perf_event.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1872,8 +1872,7 @@ static int alloc_callchain_buffers(void) * accessed from NMI. Use a temporary manual per cpu allocation * until that gets sorted out. */ - size = sizeof(*entries) + sizeof(struct perf_callchain_entry *) * - num_possible_cpus(); + size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]); entries = kzalloc(size, GFP_KERNEL); if (!entries)
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