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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2016-03-18 15:46:48 -0400
committerSasha Levin <sasha.levin@oracle.com>2016-04-18 08:49:36 -0400
commit53c83cddcf243ea06ce8b41b0328a2733b3aa88e (patch)
treebb45f52d8da3b1107bdb0737d1f2ee87962f5f0c /kernel
parent75f5d86e8020072909984e867727961594649290 (diff)
downloadlinux-linaro-stable-53c83cddcf243ea06ce8b41b0328a2733b3aa88e.tar.gz
tracing: Fix crash from reading trace_pipe with sendfile
[ Upstream commit a29054d9478d0435ab01b7544da4f674ab13f533 ] 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> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 72c71345db81..2d5909fae96d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4679,7 +4679,10 @@ 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;