[jirislaby:devel 48/48] drivers/tty/serial/samsung_tty.c:911:6: warning: variable 'count' is uninitialized when used here

From: kernel test robot
Date: Mon Apr 11 2022 - 18:17:06 EST

tree: https://git.kernel.org/pub/scm/linux/kernel/git/jirislaby/linux.git devel
head: c196e3b15cddb539135de6a3c6bcf32b89213b4c
commit: c196e3b15cddb539135de6a3c6bcf32b89213b4c [48/48] tty: serial, use kfifo
config: arm64-randconfig-r002-20220411 (https://download.01.org/0day-ci/archive/20220412/202204120654.zM4PenFU-lkp@xxxxxxxxx/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project c6e83f560f06cdfe8aa47b248d8bdc58f947274b)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install arm64 cross compiling tool for clang build
# apt-get install binutils-aarch64-linux-gnu
# https://git.kernel.org/pub/scm/linux/kernel/git/jirislaby/linux.git/commit/?id=c196e3b15cddb539135de6a3c6bcf32b89213b4c
git remote add jirislaby https://git.kernel.org/pub/scm/linux/kernel/git/jirislaby/linux.git
git fetch --no-tags jirislaby devel
git checkout c196e3b15cddb539135de6a3c6bcf32b89213b4c
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash drivers/tty/serial/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

>> drivers/tty/serial/samsung_tty.c:911:6: warning: variable 'count' is uninitialized when used here [-Wuninitialized]
if (count > port->fifosize) {
^~~~~
drivers/tty/serial/samsung_tty.c:877:11: note: initialize the variable 'count' to silence this warning
int count, dma_count = 0;
^
= 0
1 warning generated.
--
>> drivers/tty/serial/atmel_serial.c:927:34: warning: variable 'part2_len' set but not used [-Wunused-but-set-variable]
unsigned int tx_len, part1_len, part2_len, sg_len;
^
>> drivers/tty/serial/atmel_serial.c:927:23: warning: variable 'part1_len' set but not used [-Wunused-but-set-variable]
unsigned int tx_len, part1_len, part2_len, sg_len;
^
>> drivers/tty/serial/atmel_serial.c:985:13: warning: variable 'sg_len' is uninitialized when used here [-Wuninitialized]
sg_len,
^~~~~~
drivers/tty/serial/atmel_serial.c:927:51: note: initialize the variable 'sg_len' to silence this warning
unsigned int tx_len, part1_len, part2_len, sg_len;
^
= 0
3 warnings generated.
--
>> drivers/tty/serial/serial-tegra.c:584:25: warning: variable 'count' is uninitialized when used here [-Wuninitialized]
if (tup->use_tx_pio || count < TEGRA_UART_MIN_DMA)
^~~~~
drivers/tty/serial/serial-tegra.c:571:21: note: initialize the variable 'count' to silence this warning
unsigned long count;
^
= 0
>> drivers/tty/serial/serial-tegra.c:586:26: warning: variable 'tail' is uninitialized when used here [-Wuninitialized]
else if (BYTES_TO_ALIGN(tail) > 0)
^~~~
drivers/tty/serial/serial-tegra.c:39:46: note: expanded from macro 'BYTES_TO_ALIGN'
#define BYTES_TO_ALIGN(x) ((unsigned long)(x) & 0x3)
^
drivers/tty/serial/serial-tegra.c:570:20: note: initialize the variable 'tail' to silence this warning
unsigned long tail;
^
= 0
>> drivers/tty/serial/serial-tegra.c:1188:26: warning: variable 'dma_buf' is uninitialized when used here [-Wuninitialized]
tup->tx_dma_buf_virt = dma_buf;
^~~~~~~
drivers/tty/serial/serial-tegra.c:1140:24: note: initialize the variable 'dma_buf' to silence this warning
unsigned char *dma_buf;
^
= NULL
>> drivers/tty/serial/serial-tegra.c:1189:26: warning: variable 'dma_phys' is uninitialized when used here [-Wuninitialized]
tup->tx_dma_buf_phys = dma_phys;
^~~~~~~~
drivers/tty/serial/serial-tegra.c:1141:21: note: initialize the variable 'dma_phys' to silence this warning
dma_addr_t dma_phys;
^
= 0
4 warnings generated.


vim +/count +911 drivers/tty/serial/samsung_tty.c

29bef79908459d drivers/tty/serial/samsung.c Robert Baldyga 2014-12-10 892
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 893 if (port->x_char) {
8fba6c0c4c4a52 drivers/tty/serial/samsung_tty.c Hyunki Koo 2020-05-06 894 wr_reg(port, S3C2410_UTXH, port->x_char);
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 895 port->icount.tx++;
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 896 port->x_char = 0;
ad5613b98a48e7 drivers/tty/serial/samsung_tty.c Hector Martin 2021-03-05 897 return;
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 898 }
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 899
25985edcedea63 drivers/tty/serial/samsung.c Lucas De Marchi 2011-03-30 900 /* if there isn't anything more to transmit, or the uart is now
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 901 * stopped, disable the uart and exit
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 902 */
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 903
c196e3b15cddb5 drivers/tty/serial/samsung_tty.c Jiri Slaby 2022-01-05 904 if (kfifo_is_empty(&tport->xmit_fifo) || uart_tx_stopped(port)) {
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 905 s3c24xx_serial_stop_tx(port);
ad5613b98a48e7 drivers/tty/serial/samsung_tty.c Hector Martin 2021-03-05 906 return;
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 907 }
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 908
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 909 /* try and drain the buffer... */
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 910
736cd79f483fd7 drivers/tty/serial/samsung.c Robert Baldyga 2015-07-31 @911 if (count > port->fifosize) {
29bef79908459d drivers/tty/serial/samsung.c Robert Baldyga 2014-12-10 912 count = port->fifosize;
736cd79f483fd7 drivers/tty/serial/samsung.c Robert Baldyga 2015-07-31 913 dma_count = 0;
736cd79f483fd7 drivers/tty/serial/samsung.c Robert Baldyga 2015-07-31 914 }
736cd79f483fd7 drivers/tty/serial/samsung.c Robert Baldyga 2015-07-31 915
c196e3b15cddb5 drivers/tty/serial/samsung_tty.c Jiri Slaby 2022-01-05 916 while (!(rd_regl(port, S3C2410_UFSTAT) & ourport->info->tx_fifofull)) {
c196e3b15cddb5 drivers/tty/serial/samsung_tty.c Jiri Slaby 2022-01-05 917 unsigned char ch;
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 918
c196e3b15cddb5 drivers/tty/serial/samsung_tty.c Jiri Slaby 2022-01-05 919 if (!kfifo_get(&tport->xmit_fifo, &ch))
c196e3b15cddb5 drivers/tty/serial/samsung_tty.c Jiri Slaby 2022-01-05 920 break;
c196e3b15cddb5 drivers/tty/serial/samsung_tty.c Jiri Slaby 2022-01-05 921 wr_reg(port, S3C2410_UTXH, ch);
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 922 port->icount.tx++;
736cd79f483fd7 drivers/tty/serial/samsung.c Robert Baldyga 2015-07-31 923 count--;
736cd79f483fd7 drivers/tty/serial/samsung.c Robert Baldyga 2015-07-31 924 }
736cd79f483fd7 drivers/tty/serial/samsung.c Robert Baldyga 2015-07-31 925
736cd79f483fd7 drivers/tty/serial/samsung.c Robert Baldyga 2015-07-31 926 if (!count && dma_count) {
736cd79f483fd7 drivers/tty/serial/samsung.c Robert Baldyga 2015-07-31 927 s3c24xx_serial_start_tx_dma(ourport, dma_count);
ad5613b98a48e7 drivers/tty/serial/samsung_tty.c Hector Martin 2021-03-05 928 return;
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 929 }
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 930
c196e3b15cddb5 drivers/tty/serial/samsung_tty.c Jiri Slaby 2022-01-05 931 if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS)
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 932 uart_write_wakeup(port);
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 933
c196e3b15cddb5 drivers/tty/serial/samsung_tty.c Jiri Slaby 2022-01-05 934 if (kfifo_is_empty(&tport->xmit_fifo))
b497549a035c2a drivers/serial/samsung.c Ben Dooks 2008-07-03 935 s3c24xx_serial_stop_tx(port);
ad5613b98a48e7 drivers/tty/serial/samsung_tty.c Hector Martin 2021-03-05 936 }
ad5613b98a48e7 drivers/tty/serial/samsung_tty.c Hector Martin 2021-03-05 937

:::::: The code at line 911 was first introduced by commit
:::::: 736cd79f483fd7a1e0b71e6eaddf01d8d87fbbbb serial: samsung: fix DMA for FIFO smaller than cache line size

:::::: TO: Robert Baldyga <r.baldyga@xxxxxxxxxxx>
:::::: CC: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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