[PATCH 3.10 100/268] sysrq: attach sysrq handler correctly for 32-bit kernel

Willy Tarreau
2017-06-19T18:34:29Z

From: Akinobu Mita <akinobu.mita@gmail.com>

commit 802c03881f29844af0252b6e22be5d2f65f93fd0 upstream.

The sysrq input handler should be attached to the input device which has
a left alt key.

On 32-bit kernels, some input devices which has a left alt key cannot
attach sysrq handler. Because the keybit bitmap in struct input_device_id
for sysrq is not correctly initialized. KEY_LEFTALT is 56 which is
greater than BITS_PER_LONG on 32-bit kernels.

I found this problem when using a matrix keypad device which defines
a KEY_LEFTALT (56) but doesn't have a KEY_O (24 == 56%32).

Cc: Jiri Slaby <jslaby@suse.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
drivers/tty/sysrq.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index b51c154..602c9a7 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -881,8 +881,8 @@ static const struct input_device_id sysrq_ids[] = {
{
.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
INPUT_DEVICE_ID_MATCH_KEYBIT,
- .evbit = { BIT_MASK(EV_KEY) },
- .keybit = { BIT_MASK(KEY_LEFTALT) },
+ .evbit = { [BIT_WORD(EV_KEY)] = BIT_MASK(EV_KEY) },
+ .keybit = { [BIT_WORD(KEY_LEFTALT)] = BIT_MASK(KEY_LEFTALT) },
},
{ },
};
--
2.8.0.rc2.1.gbe9624a