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

tip-bot for Ingo Molnar
2009-09-15T09:35:50Z

Commit-ID: 459ec28ab404d7afcd512ce9b855959ad301605a
Gitweb: http://git.kernel.org/tip/459ec28ab404d7afcd512ce9b855959ad301605a
Author: Ingo Molnar <mingo@elte.hu>
AuthorDate: Sun, 13 Sep 2009 17:33:44 +0200
Committer: Ingo Molnar <mingo@elte.hu>
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@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
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;
}