tracing: Fix panic when lseek() called on "trace" opened for writing

The file_ops struct for the "trace" special file defined llseek as seq_lseek().
However, if the file was opened for writing only, seq_open() was not called,
and the seek would dereference a null pointer, file->private_data.

This patch introduces a new wrapper for seq_lseek() which checks if the file
descriptor is opened for reading first. If not, it does nothing.

Cc: <[email protected]>
Signed-off-by: Slava Pestov <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>

0 files changed, 0 insertions, 0 deletions