Commit 47ee4211 authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Kamal Mostafa

tracing: Fix crash from reading trace_pipe with sendfile

commit a29054d9 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/1457641146-9068-1-git-send-email-rabin@rab.inReported-by: default avatarRabin Vincent <rabin.vincent@gmail.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
parent 59cec83a
......@@ -4917,7 +4917,10 @@ 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;
......
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