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auxdisplay: charlcd: cancel backlight work on registration failure

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With CONFIG_CHARLCD_BL_FLASH, charlcd_init() schedules bl_work before
charlcd_register() calls misc_register(). If registration fails, the
caller frees the charlcd object while delayed work still contains its
address.

Add charlcd_deinit() to cancel the delayed work and turn the backlight
off. Use it for both registration rollback and normal unregistration.

Fixes: 39f8ea4672 ("auxdisplay: charlcd: Extract character LCD core from misc/panel")
Cc: stable@vger.kernel.org
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Hongyan Xu <getshell@seu.edu.cn>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
This commit is contained in:
Hongyan Xu
2026-08-15 18:59:50 +08:00
committed by Andy Shevchenko
parent 95545ddcb3
commit e3e3bf4091
1 changed files with 14 additions and 7 deletions
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21
drivers/auxdisplay/charlcd.c
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@@ -595,6 +595,16 @@ static int charlcd_init(struct charlcd *lcd)
return 0;
}
static void charlcd_deinit(struct charlcd *lcd)
{
struct charlcd_priv *priv = charlcd_to_priv(lcd);
if (lcd->ops->backlight) {
cancel_delayed_work_sync(&priv->bl_work);
lcd->ops->backlight(lcd, CHARLCD_OFF);
}
}
struct charlcd *charlcd_alloc(unsigned int drvdata_size)
{
struct charlcd_priv *priv;
@@ -654,8 +664,10 @@ int charlcd_register(struct charlcd *lcd)
return ret;
ret = misc_register(&charlcd_dev);
if (ret)
if (ret) {
charlcd_deinit(lcd);
return ret;
}
the_charlcd = lcd;
register_reboot_notifier(&panel_notifier);
@@ -665,16 +677,11 @@ EXPORT_SYMBOL_GPL(charlcd_register);
int charlcd_unregister(struct charlcd *lcd)
{
struct charlcd_priv *priv = charlcd_to_priv(lcd);
unregister_reboot_notifier(&panel_notifier);
charlcd_puts(lcd, "\x0cLCD driver unloaded.\x1b[Lc\x1b[Lb\x1b[L-");
misc_deregister(&charlcd_dev);
the_charlcd = NULL;
if (lcd->ops->backlight) {
cancel_delayed_work_sync(&priv->bl_work);
priv->lcd.ops->backlight(&priv->lcd, CHARLCD_OFF);
}
charlcd_deinit(lcd);
return 0;
}