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| author | Steven Rostedt (Red Hat) <rostedt@goodmis.org> | 2016-03-18 15:46:48 -0400 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2016-04-11 16:44:22 +0200 |
| commit | d704928dc7d402d22a8279b584a46afc519938e8 (patch) | |
| tree | 088cc5bbd923396a56104ef0c5c86e5a78f4fe70 | |
| parent | a56c35cbb2643d668d2bf06398e9c7a2098ccfcc (diff) | |
| download | lwn-d704928dc7d402d22a8279b584a46afc519938e8.tar.gz lwn-d704928dc7d402d22a8279b584a46afc519938e8.zip | |
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: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | kernel/trace/trace.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 1b51436db225..12cff54899ee 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4362,7 +4362,10 @@ 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; |