Commit d1e7e02f authored Apr 02, 2009 by Lai Jiangshan Committed by Ingo Molnar Apr 10, 2009

tracing: disable seeking for trace_pipe_raw



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: Lai 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: Ingo Molnar <mingo@elte.hu>

parent 62b8e680

kernel/trace/trace.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -3285,7 +3285,7 @@ static int tracing_buffers_open(struct inode inode, struct file filp)

		filp->private_data = info;

		return 0;
		return nonseekable_open(inode, filp);

		out:
		kfree(info);