* [PATCH v1 1/3] auxdisplay: lcd2s: Fix lcd2s_redefine_char() feature
@ 2022-02-23 15:47 Andy Shevchenko
2022-02-23 15:47 ` [PATCH v1 2/3] auxdisplay: lcd2s: Fix memory leak in ->remove() Andy Shevchenko
` (4 more replies)
0 siblings, 5 replies; 10+ messages in thread
From: Andy Shevchenko @ 2022-02-23 15:47 UTC (permalink / raw)
To: linux-kernel; +Cc: Miguel Ojeda, Andy Shevchenko, Lars Poeschel
It seems that the lcd2s_redefine_char() has never been properly
tested. The buffer is filled by DEF_CUSTOM_CHAR command followed
by the character number (from 0 to 7), but immediately after that
these bytes are got rewritten by the decoded hex stream.
Fix the index to fill the buffer after the command and number.
Fixes: 8c9108d014c5 ("auxdisplay: add a driver for lcd2s character display")
Cc: Lars Poeschel <poeschel@lemonage.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/auxdisplay/lcd2s.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/auxdisplay/lcd2s.c b/drivers/auxdisplay/lcd2s.c
index 38ba08628ccb..ea9d75ad4f16 100644
--- a/drivers/auxdisplay/lcd2s.c
+++ b/drivers/auxdisplay/lcd2s.c
@@ -238,7 +238,7 @@ static int lcd2s_redefine_char(struct charlcd *lcd, char *esc)
if (buf[1] > 7)
return 1;
- i = 0;
+ i = 2;
shift = 0;
value = 0;
while (*esc && i < LCD2S_CHARACTER_SIZE + 2) {
--
2.34.1
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH v1 2/3] auxdisplay: lcd2s: Fix memory leak in ->remove()
2022-02-23 15:47 [PATCH v1 1/3] auxdisplay: lcd2s: Fix lcd2s_redefine_char() feature Andy Shevchenko
@ 2022-02-23 15:47 ` Andy Shevchenko
2022-03-03 1:19 ` Miguel Ojeda
2022-02-23 15:47 ` [PATCH v1 3/3] auxdisplay: lcd2s: Use proper API to free the instance of charlcd object Andy Shevchenko
` (3 subsequent siblings)
4 siblings, 1 reply; 10+ messages in thread
From: Andy Shevchenko @ 2022-02-23 15:47 UTC (permalink / raw)
To: linux-kernel; +Cc: Miguel Ojeda, Andy Shevchenko, Lars Poeschel
Once allocated the struct lcd2s_data is never freed.
Fix the memory leak by switching to devm_kzalloc().
Fixes: 8c9108d014c5 ("auxdisplay: add a driver for lcd2s character display")
Cc: Lars Poeschel <poeschel@lemonage.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/auxdisplay/lcd2s.c | 18 +++++++-----------
1 file changed, 7 insertions(+), 11 deletions(-)
diff --git a/drivers/auxdisplay/lcd2s.c b/drivers/auxdisplay/lcd2s.c
index ea9d75ad4f16..7b9cfbbaf007 100644
--- a/drivers/auxdisplay/lcd2s.c
+++ b/drivers/auxdisplay/lcd2s.c
@@ -298,6 +298,10 @@ static int lcd2s_i2c_probe(struct i2c_client *i2c,
I2C_FUNC_SMBUS_WRITE_BLOCK_DATA))
return -EIO;
+ lcd2s = devm_kzalloc(&i2c->dev, sizeof(*lcd2s), GFP_KERNEL);
+ if (!lcd2s)
+ return -ENOMEM;
+
/* Test, if the display is responding */
err = lcd2s_i2c_smbus_write_byte(i2c, LCD2S_CMD_DISPLAY_OFF);
if (err < 0)
@@ -307,12 +311,6 @@ static int lcd2s_i2c_probe(struct i2c_client *i2c,
if (!lcd)
return -ENOMEM;
- lcd2s = kzalloc(sizeof(struct lcd2s_data), GFP_KERNEL);
- if (!lcd2s) {
- err = -ENOMEM;
- goto fail1;
- }
-
lcd->drvdata = lcd2s;
lcd2s->i2c = i2c;
lcd2s->charlcd = lcd;
@@ -321,24 +319,22 @@ static int lcd2s_i2c_probe(struct i2c_client *i2c,
err = device_property_read_u32(&i2c->dev, "display-height-chars",
&lcd->height);
if (err)
- goto fail2;
+ goto fail1;
err = device_property_read_u32(&i2c->dev, "display-width-chars",
&lcd->width);
if (err)
- goto fail2;
+ goto fail1;
lcd->ops = &lcd2s_ops;
err = charlcd_register(lcd2s->charlcd);
if (err)
- goto fail2;
+ goto fail1;
i2c_set_clientdata(i2c, lcd2s);
return 0;
-fail2:
- kfree(lcd2s);
fail1:
kfree(lcd);
return err;
--
2.34.1
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH v1 3/3] auxdisplay: lcd2s: Use proper API to free the instance of charlcd object
2022-02-23 15:47 [PATCH v1 1/3] auxdisplay: lcd2s: Fix lcd2s_redefine_char() feature Andy Shevchenko
2022-02-23 15:47 ` [PATCH v1 2/3] auxdisplay: lcd2s: Fix memory leak in ->remove() Andy Shevchenko
@ 2022-02-23 15:47 ` Andy Shevchenko
2022-03-03 1:19 ` Miguel Ojeda
2022-03-02 15:47 ` [PATCH v1 1/3] auxdisplay: lcd2s: Fix lcd2s_redefine_char() feature Andy Shevchenko
` (2 subsequent siblings)
4 siblings, 1 reply; 10+ messages in thread
From: Andy Shevchenko @ 2022-02-23 15:47 UTC (permalink / raw)
To: linux-kernel; +Cc: Miguel Ojeda, Andy Shevchenko, Lars Poeschel
While it might work, the current approach is fragile in a few ways:
- whenever members in the structure are shuffled, the pointer will be wrong
- the resource freeing may include more than covered by kfree()
Fix this by using charlcd_free() call instead of kfree().
Fixes: 8c9108d014c5 ("auxdisplay: add a driver for lcd2s character display")
Cc: Lars Poeschel <poeschel@lemonage.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/auxdisplay/lcd2s.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/auxdisplay/lcd2s.c b/drivers/auxdisplay/lcd2s.c
index 7b9cfbbaf007..2578b2d45439 100644
--- a/drivers/auxdisplay/lcd2s.c
+++ b/drivers/auxdisplay/lcd2s.c
@@ -336,7 +336,7 @@ static int lcd2s_i2c_probe(struct i2c_client *i2c,
return 0;
fail1:
- kfree(lcd);
+ charlcd_free(lcd2s->charlcd);
return err;
}
@@ -345,7 +345,7 @@ static int lcd2s_i2c_remove(struct i2c_client *i2c)
struct lcd2s_data *lcd2s = i2c_get_clientdata(i2c);
charlcd_unregister(lcd2s->charlcd);
- kfree(lcd2s->charlcd);
+ charlcd_free(lcd2s->charlcd);
return 0;
}
--
2.34.1
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH v1 1/3] auxdisplay: lcd2s: Fix lcd2s_redefine_char() feature
2022-02-23 15:47 [PATCH v1 1/3] auxdisplay: lcd2s: Fix lcd2s_redefine_char() feature Andy Shevchenko
2022-02-23 15:47 ` [PATCH v1 2/3] auxdisplay: lcd2s: Fix memory leak in ->remove() Andy Shevchenko
2022-02-23 15:47 ` [PATCH v1 3/3] auxdisplay: lcd2s: Use proper API to free the instance of charlcd object Andy Shevchenko
@ 2022-03-02 15:47 ` Andy Shevchenko
2022-03-02 16:12 ` Geert Uytterhoeven
2022-03-03 1:18 ` Miguel Ojeda
4 siblings, 0 replies; 10+ messages in thread
From: Andy Shevchenko @ 2022-03-02 15:47 UTC (permalink / raw)
To: linux-kernel, Geert Uytterhoeven; +Cc: Miguel Ojeda, Lars Poeschel
On Wed, Feb 23, 2022 at 05:47:16PM +0200, Andy Shevchenko wrote:
> It seems that the lcd2s_redefine_char() has never been properly
> tested. The buffer is filled by DEF_CUSTOM_CHAR command followed
> by the character number (from 0 to 7), but immediately after that
> these bytes are got rewritten by the decoded hex stream.
>
> Fix the index to fill the buffer after the command and number.
Any comments on this, please? There are fixes and seems auxdisplay subsystem
is a bit lagging... Should we worry about?
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v1 1/3] auxdisplay: lcd2s: Fix lcd2s_redefine_char() feature
2022-02-23 15:47 [PATCH v1 1/3] auxdisplay: lcd2s: Fix lcd2s_redefine_char() feature Andy Shevchenko
` (2 preceding siblings ...)
2022-03-02 15:47 ` [PATCH v1 1/3] auxdisplay: lcd2s: Fix lcd2s_redefine_char() feature Andy Shevchenko
@ 2022-03-02 16:12 ` Geert Uytterhoeven
2022-03-03 1:18 ` Miguel Ojeda
4 siblings, 0 replies; 10+ messages in thread
From: Geert Uytterhoeven @ 2022-03-02 16:12 UTC (permalink / raw)
To: Andy Shevchenko; +Cc: Linux Kernel Mailing List, Miguel Ojeda, Lars Poeschel
On Thu, Feb 24, 2022 at 2:03 AM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
> It seems that the lcd2s_redefine_char() has never been properly
> tested. The buffer is filled by DEF_CUSTOM_CHAR command followed
> by the character number (from 0 to 7), but immediately after that
> these bytes are got rewritten by the decoded hex stream.
>
> Fix the index to fill the buffer after the command and number.
>
> Fixes: 8c9108d014c5 ("auxdisplay: add a driver for lcd2s character display")
> Cc: Lars Poeschel <poeschel@lemonage.de>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v1 1/3] auxdisplay: lcd2s: Fix lcd2s_redefine_char() feature
2022-02-23 15:47 [PATCH v1 1/3] auxdisplay: lcd2s: Fix lcd2s_redefine_char() feature Andy Shevchenko
` (3 preceding siblings ...)
2022-03-02 16:12 ` Geert Uytterhoeven
@ 2022-03-03 1:18 ` Miguel Ojeda
2022-03-03 10:46 ` Miguel Ojeda
4 siblings, 1 reply; 10+ messages in thread
From: Miguel Ojeda @ 2022-03-03 1:18 UTC (permalink / raw)
To: Andy Shevchenko; +Cc: linux-kernel, Miguel Ojeda, Lars Poeschel
On Wed, Feb 23, 2022 at 4:47 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> It seems that the lcd2s_redefine_char() has never been properly
> tested. The buffer is filled by DEF_CUSTOM_CHAR command followed
> by the character number (from 0 to 7), but immediately after that
> these bytes are got rewritten by the decoded hex stream.
>
> Fix the index to fill the buffer after the command and number.
Thanks Andy, queued.
Cheers,
Miguel
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v1 2/3] auxdisplay: lcd2s: Fix memory leak in ->remove()
2022-02-23 15:47 ` [PATCH v1 2/3] auxdisplay: lcd2s: Fix memory leak in ->remove() Andy Shevchenko
@ 2022-03-03 1:19 ` Miguel Ojeda
0 siblings, 0 replies; 10+ messages in thread
From: Miguel Ojeda @ 2022-03-03 1:19 UTC (permalink / raw)
To: Andy Shevchenko; +Cc: linux-kernel, Miguel Ojeda, Lars Poeschel
On Wed, Feb 23, 2022 at 4:47 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> Once allocated the struct lcd2s_data is never freed.
> Fix the memory leak by switching to devm_kzalloc().
>
> Fixes: 8c9108d014c5 ("auxdisplay: add a driver for lcd2s character display")
> Cc: Lars Poeschel <poeschel@lemonage.de>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Thanks Andy, queued.
Cheers,
Miguel
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v1 3/3] auxdisplay: lcd2s: Use proper API to free the instance of charlcd object
2022-02-23 15:47 ` [PATCH v1 3/3] auxdisplay: lcd2s: Use proper API to free the instance of charlcd object Andy Shevchenko
@ 2022-03-03 1:19 ` Miguel Ojeda
0 siblings, 0 replies; 10+ messages in thread
From: Miguel Ojeda @ 2022-03-03 1:19 UTC (permalink / raw)
To: Andy Shevchenko; +Cc: linux-kernel, Miguel Ojeda, Lars Poeschel
On Wed, Feb 23, 2022 at 4:47 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> While it might work, the current approach is fragile in a few ways:
> - whenever members in the structure are shuffled, the pointer will be wrong
> - the resource freeing may include more than covered by kfree()
>
> Fix this by using charlcd_free() call instead of kfree().
>
> Fixes: 8c9108d014c5 ("auxdisplay: add a driver for lcd2s character display")
> Cc: Lars Poeschel <poeschel@lemonage.de>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Thanks Andy, queued.
Cheers,
Miguel
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v1 1/3] auxdisplay: lcd2s: Fix lcd2s_redefine_char() feature
2022-03-03 1:18 ` Miguel Ojeda
@ 2022-03-03 10:46 ` Miguel Ojeda
2022-03-03 11:02 ` Andy Shevchenko
0 siblings, 1 reply; 10+ messages in thread
From: Miguel Ojeda @ 2022-03-03 10:46 UTC (permalink / raw)
To: Andy Shevchenko; +Cc: linux-kernel, Miguel Ojeda, Lars Poeschel
On Thu, Mar 3, 2022 at 2:18 AM Miguel Ojeda
<miguel.ojeda.sandonis@gmail.com> wrote:
>
> Thanks Andy, queued.
By the way, I fixed a typo in the commit message.
Cheers,
Miguel
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v1 1/3] auxdisplay: lcd2s: Fix lcd2s_redefine_char() feature
2022-03-03 10:46 ` Miguel Ojeda
@ 2022-03-03 11:02 ` Andy Shevchenko
0 siblings, 0 replies; 10+ messages in thread
From: Andy Shevchenko @ 2022-03-03 11:02 UTC (permalink / raw)
To: Miguel Ojeda; +Cc: linux-kernel, Miguel Ojeda, Lars Poeschel
On Thu, Mar 03, 2022 at 11:46:32AM +0100, Miguel Ojeda wrote:
> On Thu, Mar 3, 2022 at 2:18 AM Miguel Ojeda
> <miguel.ojeda.sandonis@gmail.com> wrote:
> >
> > Thanks Andy, queued.
>
> By the way, I fixed a typo in the commit message.
Thank you, Miguel!
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 10+ messages in thread
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2022-03-03 1:19 ` Miguel Ojeda
2022-02-23 15:47 ` [PATCH v1 3/3] auxdisplay: lcd2s: Use proper API to free the instance of charlcd object Andy Shevchenko
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