Re: [PATCH] spi: rspi: avoid uninitialized variable access

From: Hiep Cao Minh
Date: Thu Nov 10 2016 - 19:58:50 EST


Hi Arnd,

On 11/10/2016 07:51 PM, Arnd Bergmann wrote:
On Thursday, November 10, 2016 6:25:56 PM CET Hiep Cao Minh wrote:
Hi Arnd,

Thanks for your fixed patch.

On 11/08/2016 10:46 PM, Arnd Bergmann wrote:
The newly introduced rspi_pio_transfer_in_or_our() function must
take either a valid 'rx' or 'tx' pointer, and has undefined behavior
if both are NULL, as found by 'gcc -Wmaybe-unintialized':

drivers/spi/spi-rspi.c: In function 'rspi_pio_transfer_in_or_our':
drivers/spi/spi-rspi.c:558:5: error: 'len' may be used uninitialized in this function [-Werror=maybe-uninitialized]
Could you tell me what kind of GCC are you using?
I'd like to reproduce it on my environment, too.
I am using the Linaro's gcc of
"gcc-linaro-arm-linux-gnueabihf-4.8-2014.04_linux".
But there is no error message like this on my environment.
The warning is currently disabled in mainline Linux, but I'm trying to
address this and hope to still get a revert of 6e8d666e9253 ("Disable
"maybe-uninitialized" warning globally") into v4.9.

You can build with "make EXTRA_CFLAGS=-Wmaybe-uninitialized" in
the meantime.
Thanks,
I used your command and found the warning.

Best regards,
Hiep
Jinzai Solution Inc,