* [PATCH] video/fbdev/via: check ioremap return value in viafb_lcd_get_mobile_state
@ 2026-03-10 1:14 Wang Jun
2026-03-10 16:36 ` Helge Deller
0 siblings, 1 reply; 2+ messages in thread
From: Wang Jun @ 2026-03-10 1:14 UTC (permalink / raw)
To: Florian Tobias Schandinat, Helge Deller
Cc: linux-fbdev, dri-devel, linux-kernel, gszhai, 25125332, 25125283,
23120469, Wang Jun
The function viafb_lcd_get_mobile_state() calls ioremap() without
checking the return value. If ioremap() fails (returns NULL), the
subsequent readw() will cause a NULL pointer dereference.
This patch adds a proper NULL check after ioremap() and returns
-ENOMEM in case of failure.
Signed-off-by: Wang Jun <1742789905@qq.com>
---
drivers/video/fbdev/via/lcd.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/video/fbdev/via/lcd.c b/drivers/video/fbdev/via/lcd.c
index 8673fced8749..91359d2b64fb 100644
--- a/drivers/video/fbdev/via/lcd.c
+++ b/drivers/video/fbdev/via/lcd.c
@@ -954,6 +954,10 @@ bool viafb_lcd_get_mobile_state(bool *mobile)
u16 start_pattern;
biosptr = ioremap(romaddr, 0x10000);
+ if (!biosptr) {
+ DEBUG_MSG(KERN_ERR " Failed to remap BIOS memory\n");
+ return false;
+ }
start_pattern = readw(biosptr);
/* Compare pattern */
--
2.43.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] video/fbdev/via: check ioremap return value in viafb_lcd_get_mobile_state
2026-03-10 1:14 [PATCH] video/fbdev/via: check ioremap return value in viafb_lcd_get_mobile_state Wang Jun
@ 2026-03-10 16:36 ` Helge Deller
0 siblings, 0 replies; 2+ messages in thread
From: Helge Deller @ 2026-03-10 16:36 UTC (permalink / raw)
To: Wang Jun, Florian Tobias Schandinat
Cc: linux-fbdev, dri-devel, linux-kernel, gszhai, 25125332, 25125283,
23120469
On 3/10/26 02:14, Wang Jun wrote:
> The function viafb_lcd_get_mobile_state() calls ioremap() without
> checking the return value. If ioremap() fails (returns NULL), the
> subsequent readw() will cause a NULL pointer dereference.
correct.
> This patch adds a proper NULL check after ioremap()
yes.
> and returns
> -ENOMEM in case of failure.
You return "false", not -ENOMEM.
Anyway, I corrected this, dropped the DEBUG_MSG() call and applied it
to the fbdev git tree.
Thanks!
Helge
> Signed-off-by: Wang Jun <1742789905@qq.com>
> ---
> drivers/video/fbdev/via/lcd.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/video/fbdev/via/lcd.c b/drivers/video/fbdev/via/lcd.c
> index 8673fced8749..91359d2b64fb 100644
> --- a/drivers/video/fbdev/via/lcd.c
> +++ b/drivers/video/fbdev/via/lcd.c
> @@ -954,6 +954,10 @@ bool viafb_lcd_get_mobile_state(bool *mobile)
> u16 start_pattern;
>
> biosptr = ioremap(romaddr, 0x10000);
> + if (!biosptr) {
> + DEBUG_MSG(KERN_ERR " Failed to remap BIOS memory\n");
> + return false;
> + }
> start_pattern = readw(biosptr);
>
> /* Compare pattern */
^ permalink raw reply [flat|nested] 2+ messages in thread
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2026-03-10 1:14 [PATCH] video/fbdev/via: check ioremap return value in viafb_lcd_get_mobile_state Wang Jun
2026-03-10 16:36 ` Helge Deller
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