3.2.80-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: "Steven Rostedt (Red Hat)" <[email protected]> commit a29054d9478d0435ab01b7544da4f674ab13f533 upstream. If tracing contains data and the trace_pipe file is read with sendfile(), then it can trigger a NULL pointer dereference and various BUG_ON within the VM code. There's a patch to fix this in the splice_to_pipe() code, but it's also a good idea to not let that happen from trace_pipe either. Link: http://lkml.kernel.org/r/[email protected] Reported-by: Rabin Vincent <[email protected]> Signed-off-by: Steven Rostedt <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> --- kernel/trace/trace.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3565,7 +3565,10 @@ static ssize_t tracing_splice_read_pipe( spd.nr_pages = i; - ret = splice_to_pipe(pipe, &spd); + if (i) + ret = splice_to_pipe(pipe, &spd); + else + ret = 0; out: splice_shrink_spd(&spd); return ret;
