HID: intel_ish-hid: fix potential uninitialized data usage
authorArnd Bergmann <arnd@arndb.de>
Thu, 18 May 2017 20:21:40 +0000 (22:21 +0200)
committerJiri Kosina <jkosina@suse.cz>
Tue, 30 May 2017 12:11:52 +0000 (14:11 +0200)
commit1260662fa3f293042fb0ae124c9a621f29f5bcab
tree663e37096740456d4e7d2e1a8b18e125090b78ba
parent7af4c727c7b6104f94f2ffc3d0899e75a9cc1e55
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 <arnd@arndb.de>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
drivers/hid/intel-ish-hid/ishtp/client.c