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| author | Steven Rostedt (Red Hat) <rostedt@goodmis.org> | 2016-03-18 15:46:48 -0400 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2016-06-07 10:42:47 +0200 |
| commit | 3f3f1fce3c1af5720308ec83a3d2ffb328a028aa (patch) | |
| tree | 9247387acb276086b4a4638917a39334671bc7dd /kernel | |
| parent | e5509925495c66013d6985d7823f947540b9ceb0 (diff) | |
| download | lwn-3f3f1fce3c1af5720308ec83a3d2ffb328a028aa.tar.gz lwn-3f3f1fce3c1af5720308ec83a3d2ffb328a028aa.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
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: Willy Tarreau <w@1wt.eu>
Diffstat (limited to 'kernel')
| -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 640e4c44b170..eff26a976f02 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4351,7 +4351,10 @@ 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; |