Hi, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on stm32/stm32-next] [also build test WARNING on usb/usb-testing v5.12-rc7] [cannot apply to tty/tty-testing next-20210409] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/dillon-minfei-gmail-com/serial-stm32-optimize-spin-lock-usage/20210412-123607 base: https://git.kernel.org/pub/scm/linux/kernel/git/atorgue/stm32.git stm32-next config: riscv-randconfig-r034-20210412 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 9829f5e6b1bca9b61efc629770d28bb9014dec45) 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 riscv cross compiling tool for clang build # apt-get install binutils-riscv64-linux-gnu # https://github.com/0day-ci/linux/commit/a0e81ae10c46f768437d61cd3a3dfd4d1250b375 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review dillon-minfei-gmail-com/serial-stm32-optimize-spin-lock-usage/20210412-123607 git checkout a0e81ae10c46f768437d61cd3a3dfd4d1250b375 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv 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/stm32-usart.c:280:39: warning: variable 'flags' is uninitialized when used here [-Wuninitialized] spin_unlock_irqrestore(&port->lock, flags); ^~~~~ drivers/tty/serial/stm32-usart.c:217:24: note: initialize the variable 'flags' to silence this warning unsigned long c, flags; ^ = 0 1 warning generated. vim +/flags +280 drivers/tty/serial/stm32-usart.c 211 212 static void stm32_usart_receive_chars(struct uart_port *port, bool threaded) 213 { 214 struct tty_port *tport = &port->state->port; 215 struct stm32_port *stm32_port = to_stm32_port(port); 216 const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; 217 unsigned long c, flags; 218 u32 sr; 219 char flag; 220 221 if (irqd_is_wakeup_set(irq_get_irq_data(port->irq))) 222 pm_wakeup_event(tport->tty->dev, 0); 223 224 while (stm32_usart_pending_rx(port, &sr, &stm32_port->last_res, 225 threaded)) { 226 sr |= USART_SR_DUMMY_RX; 227 flag = TTY_NORMAL; 228 229 /* 230 * Status bits has to be cleared before reading the RDR: 231 * In FIFO mode, reading the RDR will pop the next data 232 * (if any) along with its status bits into the SR. 233 * Not doing so leads to misalignement between RDR and SR, 234 * and clear status bits of the next rx data. 235 * 236 * Clear errors flags for stm32f7 and stm32h7 compatible 237 * devices. On stm32f4 compatible devices, the error bit is 238 * cleared by the sequence [read SR - read DR]. 239 */ 240 if ((sr & USART_SR_ERR_MASK) && ofs->icr != UNDEF_REG) 241 writel_relaxed(sr & USART_SR_ERR_MASK, 242 port->membase + ofs->icr); 243 244 c = stm32_usart_get_char(port, &sr, &stm32_port->last_res); 245 port->icount.rx++; 246 if (sr & USART_SR_ERR_MASK) { 247 if (sr & USART_SR_ORE) { 248 port->icount.overrun++; 249 } else if (sr & USART_SR_PE) { 250 port->icount.parity++; 251 } else if (sr & USART_SR_FE) { 252 /* Break detection if character is null */ 253 if (!c) { 254 port->icount.brk++; 255 if (uart_handle_break(port)) 256 continue; 257 } else { 258 port->icount.frame++; 259 } 260 } 261 262 sr &= port->read_status_mask; 263 264 if (sr & USART_SR_PE) { 265 flag = TTY_PARITY; 266 } else if (sr & USART_SR_FE) { 267 if (!c) 268 flag = TTY_BREAK; 269 else 270 flag = TTY_FRAME; 271 } 272 } 273 274 if (uart_handle_sysrq_char(port, c)) 275 continue; 276 uart_insert_char(port, sr, USART_SR_ORE, c, flag); 277 } 278 279 if (threaded) > 280 spin_unlock_irqrestore(&port->lock, flags); 281 else 282 spin_unlock(&port->lock); 283 284 tty_flip_buffer_push(tport); 285 286 if (threaded) 287 spin_lock_irqsave(&port->lock, flags); 288 else 289 spin_lock(&port->lock); 290 } 291 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
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