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auxdisplay: charlcd: checking for pointer reference before dereferencing

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Check if the pointer lcd->ops->init_display exists before dereferencing it.
If a driver called charlcd_init() without defining the ops, this would
return segmentation fault, as happened to me when implementing a charlcd
driver.  Checking the pointer before dereferencing protects from
segmentation fault.

Signed-off-by: Luiz Sampaio <sampaio.ime@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This commit is contained in:
Luiz Sampaio 2021-11-09 19:07:32 -03:00 • committed by Miguel Ojeda
parent 94047df12f
commit 4daa9ff89e
1 changed files with 3 additions and 0 deletions
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3
drivers/auxdisplay/charlcd.c
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@ -578,6 +578,9 @@ static int charlcd_init(struct charlcd *lcd)
* Since charlcd_init_display() needs to write data, we have to * Since charlcd_init_display() needs to write data, we have to
* enable mark the LCD initialized just before. * enable mark the LCD initialized just before.
*/ */
if (WARN_ON(!lcd->ops->init_display))
return -EINVAL;
ret = lcd->ops->init_display(lcd); ret = lcd->ops->init_display(lcd);
if (ret) if (ret)
return ret; return ret;