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authorStephane Eranian <eranian@google.com>2013-10-17 19:32:15 +0200
committerArnaldo Carvalho de Melo <acme@redhat.com>2013-10-17 16:27:14 -0300
commit3090ffb5a2515990182f3f55b0688a7817325488 (patch)
treea867d484f48cd124f3333ee6d10b120d2b9ac784 /kernel
parent3b16ff89676d9902dc39976aee3cb0314ee37d93 (diff)
perf: Disable PERF_RECORD_MMAP2 support
For now, we disable the extended MMAP record support (MMAP2). We have identified cases where it would not report the correct mapping information, clone(VM_CLONE) but with separate pids. We will revisit the support once we find a solution for this case. The patch changes the kernel to return EINVAL if attr->mmap2 is set. The patch also modifies the perf tool to use regular PERF_RECORD_MMAP for synthetic events and it also prevents the tool from requesting attr->mmap2 mode because the kernel would reject it. The support will be revisited once the kenrel interface is updated. In V2, we reduce the patch to the strict minimum. In V3, we avoid calling perf_event_open() with mmap2 set because we know it will fail and require fallback retry. Signed-off-by: Stephane Eranian <eranian@google.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131017173215.GA8820@quad Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index d49a9d29334..953c1434837 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6767,6 +6767,10 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr,
if (ret)
return -EFAULT;
+ /* disabled for now */
+ if (attr->mmap2)
+ return -EINVAL;
+
if (attr->__reserved_1)
return -EINVAL;