Merge branch 'tip/perf/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/urgent

Pull an ftrace ring-buffer fix from Steve Rostedt:

 * fix kernel crash when changing the size of the ring-buffer on
   boxes where possible_cpus != online_cpus.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 6420cda62336..1d0f6a8a0e5e 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1486,6 +1486,11 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,
         if (!buffer)
                 return size;
 
+        /* Make sure the requested buffer exists */
+        if (cpu_id != RING_BUFFER_ALL_CPUS &&
+            !cpumask_test_cpu(cpu_id, buffer->cpumask))
+                return size;
+
         size = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
         size *= BUF_PAGE_SIZE;