From e4762c2721f88c72bca6d356b224d39846dc1c06 Mon Sep 17 00:00:00 2001 From: Douglas Bagnall Date: Sun, 24 Jun 2012 20:58:06 +1200 Subject: [PATCH] Avoid sysfs oops when an rc_dev's raw device is absent For some reason, when the lirc daemon learns that a usb remote control has been unplugged, it wants to read the sysfs attributes of the disappearing device. This is useful for uncovering transient inconsistencies, but less so for keeping the system running when such inconsistencies exist. Under some circumstances (like every time I unplug my dvb stick from my laptop), lirc catches an rc_dev whose raw event handler has been removed (presumably by ir_raw_event_unregister), and proceeds to interrogate the raw protocols supported by the NULL pointer. This patch avoids the NULL dereference, and ignores the issue of how this state of affairs came about in the first place. --- drivers/media/rc/rc-main.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c index 6e16b09..58789c9 100644 --- a/drivers/media/rc/rc-main.c +++ b/drivers/media/rc/rc-main.c @@ -775,10 +775,12 @@ static ssize_t show_protocols(struct device *device, if (dev->driver_type == RC_DRIVER_SCANCODE) { enabled = dev->rc_map.rc_type; allowed = dev->allowed_protos; - } else { + } else if (dev->raw) { enabled = dev->raw->enabled_protocols; allowed = ir_raw_get_allowed_protocols(); } + else + return -EINVAL; IR_dprintk(1, "allowed - 0x%llx, enabled - 0x%llx\n", (long long)allowed, -- 1.7.9.5