From: Qiujun Huang <hqjagain@xxxxxxxxx> commit 0a1754b2a97efa644aa6e84d1db5b17c42251483 upstream. 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@xxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Fixes: d60da506cbeb3 ("tracing: Add a resize function to make one buffer equivalent to another buffer") Signed-off-by: Qiujun Huang <hqjagain@xxxxxxxxx> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/trace/ring_buffer.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1952,18 +1952,18 @@ int ring_buffer_resize(struct trace_buff { 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_buff } mutex_unlock(&buffer->mutex); - return size; + return 0; out_err: for_each_buffer_cpu(buffer, cpu) {
