From a31c99713bb3e130d34039a7a073a9d815af90a0 Mon Sep 17 00:00:00 2001 From: Douglas Bagnall Date: Fri, 6 Jul 2012 23:27:57 -0300 Subject: media: Avoid sysfs oops when an rc_dev's raw device is absent commit 720bb6436ff30fccad05cf5bdf961ea5b1f5686d upstream. 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. Version 2 incorporates changes recommended by Mauro Carvalho Chehab (-ENODEV instead of -EINVAL, and a signed-off-by). Signed-off-by: Douglas Bagnall Signed-off-by: Mauro Carvalho Chehab Cc: Herton Ronaldo Krzesinski Signed-off-by: Greg Kroah-Hartman --- drivers/media/rc/rc-main.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c index 6e16b09c24a..cabc19c1051 100644 --- a/drivers/media/rc/rc-main.c +++ b/drivers/media/rc/rc-main.c @@ -775,10 +775,11 @@ 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 -ENODEV; IR_dprintk(1, "allowed - 0x%llx, enabled - 0x%llx\n", (long long)allowed, -- cgit v1.2.3-18-g5258