HID: bigbenff: prevent null pointer dereference

stable inclusion
from stable-v5.10.85
commit 6272b17001e6fdcf7b4a16206287010a1523fa6e
bugzilla: 186032 https://gitee.com/openeuler/kernel/issues/I4QVI4

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6272b17001e6fdcf7b4a16206287010a1523fa6e

--------------------------------

commit 918aa1ef upstream.

When emulating the device through uhid, there is a chance we don't have
output reports and so report_field is null.

Cc: stable@vger.kernel.org
Signed-off-by: NBenjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20211202095334.14399-3-benjamin.tissoires@redhat.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/hid/hid-bigbenff.c

@@ -191,7 +191,7 @@ static void bigben_worker(struct work_struct *work)
 		struct bigben_device, worker);
 	struct hid_field *report_field = bigben->report->field[0];
 
-	if (bigben->removed)
+	if (bigben->removed || !report_field)
 		return;
 
 	if (bigben->work_led) {