From: "Steven Rostedt (Google)" <rost...@goodmis.org>

As all the subbuffer order (subbuffer sizes) must be the same throughout
the ring buffer, check the order of the buffers that are doing a CPU
buffer swap in ring_buffer_swap_cpu() to make sure they are the same.

If the are not the same, then fail to do the swap, otherwise the ring
buffer will think the CPU buffer has a specific subbuffer size when it
does not.

Signed-off-by: Steven Rostedt (Google) <rost...@goodmis.org>
---
 kernel/trace/ring_buffer.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index ea3c217e4e43..2c908b4f3f68 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -5559,6 +5559,9 @@ int ring_buffer_swap_cpu(struct trace_buffer *buffer_a,
        if (cpu_buffer_a->nr_pages != cpu_buffer_b->nr_pages)
                goto out;
 
+       if (buffer_a->subbuf_order != buffer_b->subbuf_order)
+               goto out;
+
        ret = -EAGAIN;
 
        if (atomic_read(&buffer_a->record_disabled))
-- 
2.42.0



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