diff options
| author | Steven Rostedt | 2008-05-12 21:20:56 +0200 |
|---|---|---|
| committer | Thomas Gleixner | 2008-05-23 21:15:59 +0200 |
| commit | 30afdcb1de0a37a2086145a82ca3febebe47d019 (patch) | |
| tree | 866c4d195207ac37d4477f9ce09d429085532180 | |
| parent | d15f57f23eaba975309a153b23699cd0c0236974 (diff) | |
ftrace: selftest protect againt max flip
There is a slight race condition in the selftest where the max update
of the wakeup and irqs/preemption off tests can be doing a max update as
the buffers are being tested. If this happens the system can crash with
a GPF.
This patch adds the max update spinlock around the checking of the
buffers to prevent such a race.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | kernel/trace/trace_selftest.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 83e55a2000cc..395274e783b3 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -82,10 +82,12 @@ trace_test_buffer_cpu(struct trace_array *tr, struct trace_array_cpu *data) */ static int trace_test_buffer(struct trace_array *tr, unsigned long *count) { - unsigned long cnt = 0; - int cpu; - int ret = 0; + unsigned long flags, cnt = 0; + int cpu, ret = 0; + /* Don't allow flipping of max traces now */ + raw_local_irq_save(flags); + __raw_spin_lock(&ftrace_max_lock); for_each_possible_cpu(cpu) { if (!head_page(tr->data[cpu])) continue; @@ -96,6 +98,8 @@ static int trace_test_buffer(struct trace_array *tr, unsigned long *count) if (ret) break; } + __raw_spin_unlock(&ftrace_max_lock); + raw_local_irq_restore(flags); if (count) *count = cnt; |