From 69f2af2ddcfd0d9984e764bdf0953a8d9248755a Mon Sep 17 00:00:00 2001 From: =?utf8?q?Bruno=20Pr=C3=A9mont?= Date: Sat, 31 Aug 2013 14:07:48 +0200 Subject: [PATCH] HID: picolcd: Prevent NULL pointer dereference on _remove() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit 1cde501bb4655e98fb832194beb88ac73be5a05d upstream. When picolcd is switched into bootloader mode (for FW flashing) make sure not to try to dereference NULL-pointers of feature-devices during unplug/unbind. This fixes following BUG: BUG: unable to handle kernel NULL pointer dereference at 00000298 IP: [] picolcd_exit_framebuffer+0x1b/0x80 [hid_picolcd] *pde = 00000000 Oops: 0000 [#1] Modules linked in: hid_picolcd syscopyarea sysfillrect sysimgblt fb_sys_fops CPU: 0 PID: 15 Comm: khubd Not tainted 3.11.0-rc7-00002-g50d62d4 #2 EIP: 0060:[] EFLAGS: 00010292 CPU: 0 EIP is at picolcd_exit_framebuffer+0x1b/0x80 [hid_picolcd] Call Trace: [] picolcd_remove+0xcb/0x120 [hid_picolcd] [] hid_device_remove+0x59/0xc0 [] __device_release_driver+0x5a/0xb0 [] device_release_driver+0x1f/0x30 [] bus_remove_device+0x9d/0xd0 [] device_del+0xd5/0x150 [] hid_destroy_device+0x24/0x60 [] usbhid_disconnect+0x1b/0x40 ... Signed-off-by: Bruno Prémont Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman --- drivers/hid/hid-picolcd_cir.c | 3 ++- drivers/hid/hid-picolcd_fb.c | 6 +++++- 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/hid/hid-picolcd_cir.c b/drivers/hid/hid-picolcd_cir.c index e346038f0f11..59d5eb1e742c 100644 --- a/drivers/hid/hid-picolcd_cir.c +++ b/drivers/hid/hid-picolcd_cir.c @@ -145,6 +145,7 @@ void picolcd_exit_cir(struct picolcd_data *data) struct rc_dev *rdev = data->rc_dev; data->rc_dev = NULL; - rc_unregister_device(rdev); + if (rdev) + rc_unregister_device(rdev); } diff --git a/drivers/hid/hid-picolcd_fb.c b/drivers/hid/hid-picolcd_fb.c index 591f6b22aa94..c930ab8554ea 100644 --- a/drivers/hid/hid-picolcd_fb.c +++ b/drivers/hid/hid-picolcd_fb.c @@ -593,10 +593,14 @@ err_nomem: void picolcd_exit_framebuffer(struct picolcd_data *data) { struct fb_info *info = data->fb_info; - struct picolcd_fb_data *fbdata = info->par; + struct picolcd_fb_data *fbdata; unsigned long flags; + if (!info) + return; + device_remove_file(&data->hdev->dev, &dev_attr_fb_update_rate); + fbdata = info->par; /* disconnect framebuffer from HID dev */ spin_lock_irqsave(&fbdata->lock, flags); -- 2.34.1