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authorBruno Prémont <bonbons@linux-vserver.org>2013-08-31 14:07:48 +0200
committerJiri Kosina <jkosina@suse.cz>2013-09-02 13:36:50 +0200
commit1cde501bb4655e98fb832194beb88ac73be5a05d (patch)
tree86cc70fe2cc7c5e4fa875a5ada657a3825056428 /drivers/hid/hid-picolcd_fb.c
parent9e0bf92c223dabe0789714f8f85f6e26f8f9cda4 (diff)
HID: picolcd: Prevent NULL pointer dereference on _remove()
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: [<f811f56b>] 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:[<f811f56b>] EFLAGS: 00010292 CPU: 0 EIP is at picolcd_exit_framebuffer+0x1b/0x80 [hid_picolcd] Call Trace: [<f811d1ab>] picolcd_remove+0xcb/0x120 [hid_picolcd] [<c1469b09>] hid_device_remove+0x59/0xc0 [<c13464ca>] __device_release_driver+0x5a/0xb0 [<c134653f>] device_release_driver+0x1f/0x30 [<c134603d>] bus_remove_device+0x9d/0xd0 [<c13439a5>] device_del+0xd5/0x150 [<c14696a4>] hid_destroy_device+0x24/0x60 [<c1474cbb>] usbhid_disconnect+0x1b/0x40 ... Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org> Cc: stable@kernel.org Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'drivers/hid/hid-picolcd_fb.c')
-rw-r--r--drivers/hid/hid-picolcd_fb.c6
1 files changed, 5 insertions, 1 deletions
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);