From 1260662fa3f293042fb0ae124c9a621f29f5bcab Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 18 May 2017 22:21:40 +0200 Subject: [PATCH] HID: intel_ish-hid: fix potential uninitialized data usage gcc points out an uninialized pointer dereference that could happen if we ever get to recv_ishtp_cl_msg_dma() or recv_ishtp_cl_msg() with an empty &dev->read_list: drivers/hid/intel-ish-hid/ishtp/client.c: In function 'recv_ishtp_cl_msg_dma': drivers/hid/intel-ish-hid/ishtp/client.c:1049:3: error: 'cl' may be used uninitialized in this function [-Werror=maybe-uninitialized] The warning only appeared in very few randconfig builds, as the spinlocks tend to prevent gcc from tracing the variables. I only saw it in configurations that had neither SMP nor LOCKDEP enabled. As we can see, we only enter the case if 'complete_rb' is non-NULL, and then 'cl' is known to point to complete_rb->cl. Adding another initialization to the same pointer is harmless here and makes it clear to the compiler that the behavior is well-defined. Signed-off-by: Arnd Bergmann Acked-by: Srinivas Pandruvada Signed-off-by: Jiri Kosina --- drivers/hid/intel-ish-hid/ishtp/client.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/hid/intel-ish-hid/ishtp/client.c b/drivers/hid/intel-ish-hid/ishtp/client.c index aad61328f282..78d393e616a4 100644 --- a/drivers/hid/intel-ish-hid/ishtp/client.c +++ b/drivers/hid/intel-ish-hid/ishtp/client.c @@ -925,6 +925,7 @@ void recv_ishtp_cl_msg(struct ishtp_device *dev, } if (complete_rb) { + cl = complete_rb->cl; getnstimeofday(&cl->ts_rx); ++cl->recv_msg_cnt_ipc; ishtp_cl_read_complete(complete_rb); @@ -1045,6 +1046,7 @@ void recv_ishtp_cl_msg_dma(struct ishtp_device *dev, void *msg, } if (complete_rb) { + cl = complete_rb->cl; getnstimeofday(&cl->ts_rx); ++cl->recv_msg_cnt_dma; ishtp_cl_read_complete(complete_rb); -- 2.30.2