Subject: [PATCH] Fix Oops in toshiba_acpi error return path From: Andrey Borzenkov When backlight_device_register() fails, return after undo initialization, do not try to use pointer that just was reset to NULL This fixes this oops: [ 1595.177672] [] show_trace_log_lvl+0x1a/0x30 [ 1595.177706] [] show_trace+0x12/0x20 [ 1595.177718] [] dump_stack+0x15/0x20 [ 1595.177728] [] kobject_shadow_add+0x125/0x1c0 [ 1595.177754] [] kobject_add+0xa/0x10 [ 1595.177764] [] device_add+0x97/0x5d0 [ 1595.177776] [] device_register+0x12/0x20 [ 1595.177786] [] backlight_device_register+0x9f/0x110 [backlight] [ 1595.177814] [] toshiba_acpi_init+0x117/0x15e [toshiba_acpi] [ 1595.177834] [] sys_init_module+0xfd/0x14e0 [ 1595.177871] [] sysenter_past_esp+0x5f/0x99 [ 1595.177883] ======================= [ 1595.177890] Could not register toshiba backlight device [ 1595.177985] BUG: unable to handle kernel NULL pointer dereference at virtual address 00000004 ... [ 1595.394097] EIP: 0060:[] Not tainted VLI [ 1595.394101] EFLAGS: 00010282 (2.6.23-rc9-1avb #24) [ 1595.480081] EIP is at toshiba_acpi_init+0x143/0x15e [toshiba_acpi] Signed-off-by: Andrey Borzenkov --- drivers/acpi/toshiba_acpi.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/drivers/acpi/toshiba_acpi.c b/drivers/acpi/toshiba_acpi.c index 13369b4..18660cc 100644 --- a/drivers/acpi/toshiba_acpi.c +++ b/drivers/acpi/toshiba_acpi.c @@ -591,9 +591,12 @@ static int __init toshiba_acpi_init(void) NULL, &toshiba_backlight_data); if (IS_ERR(toshiba_backlight_device)) { + int ret = PTR_ERR(toshiba_backlight_device); + printk(KERN_ERR "Could not register toshiba backlight device\n"); toshiba_backlight_device = NULL; toshiba_acpi_exit(); + return ret; } toshiba_backlight_device->props.max_brightness = HCI_LCD_BRIGHTNESS_LEVELS - 1;