From 88d4f0db7fa8785859c1d637f9aac210932b6216 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 25 Jan 2011 19:40:51 +0100 Subject: [PATCH] perf: Fix alloc_callchain_buffers() 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 Cc: Frederic Weisbecker Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: David Miller Cc: Stephane Eranian CC: stable@kernel.org LKML-Reference: <1295980851.3588.351.camel@edumazet-laptop> Signed-off-by: Ingo Molnar --- kernel/perf_event.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 126a302..852ae8c 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1999,8 +1999,7 @@ 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) -- 2.7.4