With gcc 4.1.2:
drivers/mtd/spi-nor/stm32-quadspi.c: In function ‘stm32_qspi_tx_poll’:
drivers/mtd/spi-nor/stm32-quadspi.c:230: warning: ‘ret’ may be used uninitialized in this function
Indeed, if stm32_qspi_cmd.len is zero, ret will be uninitialized.
This length is passed from outside the driver using the
spi_nor.{read,write}{,_reg}() callbacks.
Several functions in drivers/mtd/spi-nor/spi-nor.c (e.g. write_enable(),
write_disable(), and erase_chip()) call spi_nor.write_reg() with a zero
length.
Fix this by returning an explicit zero on success.
Fixes: 0d43d7ab277a048c ("mtd: spi-nor: add driver for STM32 quad spi flash controller")
Signed-off-by: Geert Uytterhoeven <[email protected]>
---
drivers/mtd/spi-nor/stm32-quadspi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/mtd/spi-nor/stm32-quadspi.c b/drivers/mtd/spi-nor/stm32-quadspi.c
index 86c0931543c538c3..ad6a3e1844cbe5ec 100644
--- a/drivers/mtd/spi-nor/stm32-quadspi.c
+++ b/drivers/mtd/spi-nor/stm32-quadspi.c
@@ -240,12 +240,12 @@ static int stm32_qspi_tx_poll(struct stm32_qspi *qspi,
STM32_QSPI_FIFO_TIMEOUT_US);
if (ret) {
dev_err(qspi->dev, "fifo timeout (stat:%#x)\n", sr);
- break;
+ return ret;
}
tx_fifo(buf++, qspi->io_base + QUADSPI_DR);
}
- return ret;
+ return 0;
}
static int stm32_qspi_tx_mm(struct stm32_qspi *qspi,
--
2.7.4
Hi Geert
Thanks for your remarks.
Today only write_reg could be call with len=0 (spi-nor.c:
write_enable/disable, set_4byte, erase_chip)
But your remark make sense to prevent: gcc warning and framework
evolution ...
-In stm32-quadspi.c transfer data is enabled if tx_data is true (some
actions under this bool)
stm32_qspi_write_reg has already this protection with "!!(buf && len > 0);"
but we could extend this protection
- cmd.tx_data = true;
+ cmd.tx_data = !!(len > 0);
In : stm32_qspi_read, stm32_qspi_write, stm32_qspi_read_reg
-And to avoid gcc warning: I prefer initialize "ret" in the beginning of
function
- int ret;
+ int ret = 0;
I tested this changes, and it's ok for me.
Geert could you resend a new version, or do you prefer that I take care
of it
BR
Ludo
On 07/15/2017 10:00 AM, Geert Uytterhoeven wrote:
> With gcc 4.1.2:
>
> drivers/mtd/spi-nor/stm32-quadspi.c: In function ‘stm32_qspi_tx_poll’:
> drivers/mtd/spi-nor/stm32-quadspi.c:230: warning: ‘ret’ may be used uninitialized in this function
>
> Indeed, if stm32_qspi_cmd.len is zero, ret will be uninitialized.
> This length is passed from outside the driver using the
> spi_nor.{read,write}{,_reg}() callbacks.
>
> Several functions in drivers/mtd/spi-nor/spi-nor.c (e.g. write_enable(),
> write_disable(), and erase_chip()) call spi_nor.write_reg() with a zero
> length.
>
> Fix this by returning an explicit zero on success.
>
> Fixes: 0d43d7ab277a048c ("mtd: spi-nor: add driver for STM32 quad spi flash controller")
> Signed-off-by: Geert Uytterhoeven <[email protected]>
> ---
> drivers/mtd/spi-nor/stm32-quadspi.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/spi-nor/stm32-quadspi.c b/drivers/mtd/spi-nor/stm32-quadspi.c
> index 86c0931543c538c3..ad6a3e1844cbe5ec 100644
> --- a/drivers/mtd/spi-nor/stm32-quadspi.c
> +++ b/drivers/mtd/spi-nor/stm32-quadspi.c
> @@ -240,12 +240,12 @@ static int stm32_qspi_tx_poll(struct stm32_qspi *qspi,
> STM32_QSPI_FIFO_TIMEOUT_US);
> if (ret) {
> dev_err(qspi->dev, "fifo timeout (stat:%#x)\n", sr);
> - break;
> + return ret;
> }
> tx_fifo(buf++, qspi->io_base + QUADSPI_DR);
> }
>
> - return ret;
> + return 0;
> }
>
> static int stm32_qspi_tx_mm(struct stm32_qspi *qspi,
Hi Ludovic,
On Mon, Jul 17, 2017 at 11:56 AM, Ludovic BARRE <[email protected]> wrote:
> Today only write_reg could be call with len=0 (spi-nor.c:
> write_enable/disable, set_4byte, erase_chip)
>
> But your remark make sense to prevent: gcc warning and framework evolution
> ...
>
>
> -In stm32-quadspi.c transfer data is enabled if tx_data is true (some
> actions under this bool)
>
> stm32_qspi_write_reg has already this protection with "!!(buf && len > 0);"
>
> but we could extend this protection
>
> - cmd.tx_data = true;
> + cmd.tx_data = !!(len > 0);
>
> In : stm32_qspi_read, stm32_qspi_write, stm32_qspi_read_reg
Ah, I missed the check for !cmd->tx_data at the top of stm32_qspi_tx()
> -And to avoid gcc warning: I prefer initialize "ret" in the beginning of
> function
>
> - int ret;
> + int ret = 0;
>
> I tested this changes, and it's ok for me.
>
> Geert could you resend a new version, or do you prefer that I take care of
> it
If you initialized ret at the beginning, you lose the ability to catch newly
introduced similar bugs in the future.
> On 07/15/2017 10:00 AM, Geert Uytterhoeven wrote:
>>
>> With gcc 4.1.2:
>>
>> drivers/mtd/spi-nor/stm32-quadspi.c: In function
>> ‘stm32_qspi_tx_poll’:
>> drivers/mtd/spi-nor/stm32-quadspi.c:230: warning: ‘ret’ may be used
>> uninitialized in this function
>>
>> Indeed, if stm32_qspi_cmd.len is zero, ret will be uninitialized.
>> This length is passed from outside the driver using the
>> spi_nor.{read,write}{,_reg}() callbacks.
>>
>> Several functions in drivers/mtd/spi-nor/spi-nor.c (e.g. write_enable(),
>> write_disable(), and erase_chip()) call spi_nor.write_reg() with a zero
>> length.
>>
>> Fix this by returning an explicit zero on success.
>>
>> Fixes: 0d43d7ab277a048c ("mtd: spi-nor: add driver for STM32 quad spi
>> flash controller")
>> Signed-off-by: Geert Uytterhoeven <[email protected]>
>> ---
>> drivers/mtd/spi-nor/stm32-quadspi.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mtd/spi-nor/stm32-quadspi.c
>> b/drivers/mtd/spi-nor/stm32-quadspi.c
>> index 86c0931543c538c3..ad6a3e1844cbe5ec 100644
>> --- a/drivers/mtd/spi-nor/stm32-quadspi.c
>> +++ b/drivers/mtd/spi-nor/stm32-quadspi.c
>> @@ -240,12 +240,12 @@ static int stm32_qspi_tx_poll(struct stm32_qspi
>> *qspi,
>>
>> STM32_QSPI_FIFO_TIMEOUT_US);
>> if (ret) {
>> dev_err(qspi->dev, "fifo timeout (stat:%#x)\n",
>> sr);
>> - break;
>> + return ret;
>> }
>> tx_fifo(buf++, qspi->io_base + QUADSPI_DR);
>> }
>> - return ret;
>> + return 0;
>> }
>> static int stm32_qspi_tx_mm(struct stm32_qspi *qspi,
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
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
On 07/17/2017 12:22 PM, Geert Uytterhoeven wrote:
> Hi Ludovic,
>
> On Mon, Jul 17, 2017 at 11:56 AM, Ludovic BARRE <[email protected]> wrote:
>> Today only write_reg could be call with len=0 (spi-nor.c:
>> write_enable/disable, set_4byte, erase_chip)
>>
>> But your remark make sense to prevent: gcc warning and framework evolution
>> ...
>>
>>
>> -In stm32-quadspi.c transfer data is enabled if tx_data is true (some
>> actions under this bool)
>>
>> stm32_qspi_write_reg has already this protection with "!!(buf && len > 0);"
>>
>> but we could extend this protection
>>
>> - cmd.tx_data = true;
>> + cmd.tx_data = !!(len > 0);
>>
>> In : stm32_qspi_read, stm32_qspi_write, stm32_qspi_read_reg
>
> Ah, I missed the check for !cmd->tx_data at the top of stm32_qspi_tx()
>
>> -And to avoid gcc warning: I prefer initialize "ret" in the beginning of
>> function
>>
>> - int ret;
>> + int ret = 0;
>>
>> I tested this changes, and it's ok for me.
>>
>> Geert could you resend a new version, or do you prefer that I take care of
>> it
>
> If you initialized ret at the beginning, you lose the ability to catch newly
> introduced similar bugs in the future.
like discuss in thread https://patchwork.kernel.org/patch/9952849/ with
Arnd and Geert
Cyrille, Marek: could you take geert patch and abandon
https://patchwork.kernel.org/patch/9952849/
thanks
Acked-by: Ludovic Barre <[email protected]>
>
>> On 07/15/2017 10:00 AM, Geert Uytterhoeven wrote:
>>>
>>> With gcc 4.1.2:
>>>
>>> drivers/mtd/spi-nor/stm32-quadspi.c: In function
>>> ‘stm32_qspi_tx_poll’:
>>> drivers/mtd/spi-nor/stm32-quadspi.c:230: warning: ‘ret’ may be used
>>> uninitialized in this function
>>>
>>> Indeed, if stm32_qspi_cmd.len is zero, ret will be uninitialized.
>>> This length is passed from outside the driver using the
>>> spi_nor.{read,write}{,_reg}() callbacks.
>>>
>>> Several functions in drivers/mtd/spi-nor/spi-nor.c (e.g. write_enable(),
>>> write_disable(), and erase_chip()) call spi_nor.write_reg() with a zero
>>> length.
>>>
>>> Fix this by returning an explicit zero on success.
>>>
>>> Fixes: 0d43d7ab277a048c ("mtd: spi-nor: add driver for STM32 quad spi
>>> flash controller")
>>> Signed-off-by: Geert Uytterhoeven <[email protected]>
>>> ---
>>> drivers/mtd/spi-nor/stm32-quadspi.c | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/mtd/spi-nor/stm32-quadspi.c
>>> b/drivers/mtd/spi-nor/stm32-quadspi.c
>>> index 86c0931543c538c3..ad6a3e1844cbe5ec 100644
>>> --- a/drivers/mtd/spi-nor/stm32-quadspi.c
>>> +++ b/drivers/mtd/spi-nor/stm32-quadspi.c
>>> @@ -240,12 +240,12 @@ static int stm32_qspi_tx_poll(struct stm32_qspi
>>> *qspi,
>>>
>>> STM32_QSPI_FIFO_TIMEOUT_US);
>>> if (ret) {
>>> dev_err(qspi->dev, "fifo timeout (stat:%#x)\n",
>>> sr);
>>> - break;
>>> + return ret;
>>> }
>>> tx_fifo(buf++, qspi->io_base + QUADSPI_DR);
>>> }
>>> - return ret;
>>> + return 0;
>>> }
>>> static int stm32_qspi_tx_mm(struct stm32_qspi *qspi,
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
>
> 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
>