lkml.org 
[lkml]   [2017]   [May]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 1/5] HID: intel_ish-hid: fix potential uninitialized data usage
Date
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 <arnd@arndb.de>
---
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);
--
2.9.0
\
 
 \ /
  Last update: 2017-05-18 22:23    [W:0.214 / U:0.712 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site