tracing: Fix crash from reading trace_pipe with sendfile

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/1457641146-9068-1-git-send-email-rabin@rab.in

Cc: stable@vger.kernel.org # 2.6.30+
Reported-by: Rabin Vincent <rabin.vincent@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat) 2016-03-18 15:46:48 -04:00 committed by Steven Rostedt
parent cb86e05390
commit a29054d947

View File

@ -4954,7 +4954,10 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
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;