From: Qiujun Huang hqjagain@gmail.com

We don't need to check the new buffer size, and the return value had confused resize_buffer_duplicate_size(). ... ret = ring_buffer_resize(trace_buf->buffer, per_cpu_ptr(size_buf->data,cpu_id)->entries, cpu_id); if (ret == 0) per_cpu_ptr(trace_buf->data, cpu_id)->entries = per_cpu_ptr(size_buf->data, cpu_id)->entries; ...

Link: https://lkml.kernel.org/r/20201019142242.11560-1-hqjagain@gmail.com

Cc: stable@vger.kernel.org Fixes: d60da506cbeb3 ("tracing: Add a resize function to make one buffer equivalent to another buffer") Signed-off-by: Qiujun Huang hqjagain@gmail.com Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org --- kernel/trace/ring_buffer.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 15bf28b13e50..5c6a9c6a058f 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1952,18 +1952,18 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, { struct ring_buffer_per_cpu *cpu_buffer; unsigned long nr_pages; - int cpu, err = 0; + int cpu, err;

/* * Always succeed at resizing a non-existent buffer: */ if (!buffer) - return size; + return 0;

/* Make sure the requested buffer exists */ if (cpu_id != RING_BUFFER_ALL_CPUS && !cpumask_test_cpu(cpu_id, buffer->cpumask)) - return size; + return 0;

nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);

@@ -2119,7 +2119,7 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, }

mutex_unlock(&buffer->mutex); - return size; + return 0;

out_err: for_each_buffer_cpu(buffer, cpu) {