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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2016-03-18 15:46:48 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-04-12 09:08:59 -0700
commitaab3ba82f8445abe99f33e743e7316d0d55fee7b (patch)
tree6e9069d79eb2578a3d34d86c37e1acedf3388a91 /kernel/trace
parentaa60f652eeebb8345ed8c543d1a8d6b71f902de3 (diff)
tracing: Fix crash from reading trace_pipe with sendfile
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/1457641146-9068-1-git-send-email-rabin@rab.in Reported-by: Rabin Vincent <rabin.vincent@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/trace')
-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 d9293402ee68..8305cbb2d5a2 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4949,7 +4949,10 @@ 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;