On Sunday 07 October 2007, Andrey Borzenkov wrote:
> This fixes oops when registering backlight device fails. Attached as I
> still cannot convince kmail to not mangle long lines ...
>
> -andrey
ping ...
Subject: [PATCH] Fix Oops in toshiba_acpi error return path
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] [<c010480a>] show_trace_log_lvl+0x1a/0x30
[ 1595.177706] [<c01052a2>] show_trace+0x12/0x20
[ 1595.177718] [<c0105305>] dump_stack+0x15/0x20
[ 1595.177728] [<c01c9375>] kobject_shadow_add+0x125/0x1c0
[ 1595.177754] [<c01c941a>] kobject_add+0xa/0x10
[ 1595.177764] [<c0239a37>] device_add+0x97/0x5d0
[ 1595.177776] [<c0239f82>] device_register+0x12/0x20
[ 1595.177786] [<dfd912df>] backlight_device_register+0x9f/0x110 [backlight]
[ 1595.177814] [<df861117>] toshiba_acpi_init+0x117/0x15e [toshiba_acpi]
[ 1595.177834] [<c013e28d>] sys_init_module+0xfd/0x14e0
[ 1595.177871] [<c0104112>] 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:[<df861143>] 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 <arvidjaar@xxxxxxx>
---
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;
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