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Subject[PATCH 2/2] auxdisplay: charlcd: checking for pointer reference before dereferencing
Date
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>
---
drivers/auxdisplay/charlcd.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c
index cca3b600c0ba..47363fb2fe94 100644
--- a/drivers/auxdisplay/charlcd.c
+++ b/drivers/auxdisplay/charlcd.c
@@ -578,6 +578,9 @@ static int charlcd_init(struct charlcd *lcd)
* Since charlcd_init_display() needs to write data, we have to
* enable mark the LCD initialized just before.
*/
+ if (!lcd->ops->init_display)
+ return -EFAULT;
+
ret = lcd->ops->init_display(lcd);
if (ret)
return ret;
--
2.33.1
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