auxdisplay: ht16k33: don't access uninitialized data
authorArnd Bergmann <arnd@arndb.de>
Tue, 28 Mar 2017 10:11:49 +0000 (12:11 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 8 Apr 2017 15:48:19 +0000 (17:48 +0200)
commite1f990c24d14a80dd9b16ea967c9b76dbba501a3
tree329aa6b851a9bdcd3e2b0a0243c10cc6db58fde4
parentc7c3f096eb5e721d8522ba060fa621ea906ef738
auxdisplay: ht16k33: don't access uninitialized data

gcc-7.0.1 points out that we copy uninitialized data from the stack
into a per-device structure:

drivers/auxdisplay/ht16k33.c: In function 'ht16k33_keypad_irq_thread':
arch/x86/include/asm/string_32.h:78:16: error: 'new_state' may be used uninitialized in this function [-Werror=maybe-uninitialized]
arch/x86/include/asm/string_32.h:79:22: error: '*((void *)&new_state+4)' may be used uninitialized in this function [-Werror=maybe-uninitialized]

The access is harmless because we never read the data, but we are better
off not doing this, so this changes the code to only copy the data
that was actually initialized. To make sure we don't overflow the
stack with an incorrect DT, we also need to add a sanity checkin the
probe function.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Robin van der Gracht <robin@protonic.nl>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/auxdisplay/ht16k33.c