[tip:perfcounters/core] perf_counter: Allow mmap if paranoid checks are turned off

[tip-bot for Ingo Molnar]

Commit-ID:  459ec28ab404d7afcd512ce9b855959ad301605a
Gitweb:     http://git.kernel.org/tip/459ec28ab404d7afcd512ce9b855959ad301605a
Author:     Ingo Molnar <mingo@xxxxxxx>
AuthorDate: Sun, 13 Sep 2009 17:33:44 +0200
Committer:  Ingo Molnar <mingo@xxxxxxx>
CommitDate: Sun, 13 Sep 2009 17:33:44 +0200

perf_counter: Allow mmap if paranoid checks are turned off

Before:

  $ perf sched record -f sleep 1
  Error: failed to mmap with 1 (Operation not permitted)

After:

  $ perf sched record -f sleep 1
  [ perf record: Captured and wrote 0.095 MB perf.data (~4161 samples) ]

Note, this is only allowed if perfcounter_paranoid is set to
the most permissive (non-default) value of -1.

Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>


---
 kernel/perf_counter.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index e0d91fd..667ab25 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -2315,7 +2315,8 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 	lock_limit >>= PAGE_SHIFT;
 	locked = vma->vm_mm->locked_vm + extra;
 
-	if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
+	if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
+		!capable(CAP_IPC_LOCK)) {
 		ret = -EPERM;
 		goto unlock;
 	}
--
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