• Lai Jiangshan's avatar
    tracing: disable seeking for trace_pipe_raw · d1e7e02f
    Lai Jiangshan authored
    
    
    Impact: disable pread()
    
    We set tracing_buffers_fops.llseek to no_llseek,
    but we can still perform pread() to read this file.
    
    That is not expected.
    
    This fix uses nonseekable_open() to disable it.
    
    tracing_buffers_fops.llseek is still set to no_llseek,
    it mark this file is a "non-seekable device" and is used by
    sys_splice(). See also do_splice() or manual of splice(2):
    
    ERRORS
           EINVAL Target file system doesn't support  splicing;
                  neither  of the descriptors refers to a pipe;
                  or offset given for non-seekable device.
    Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
    Cc: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: Steven Rostedt <srostedt@redhat.com>
    LKML-Reference: <49D46668.8030806@cn.fujitsu.com>
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    d1e7e02f