Hi lkp, Thanks for the reminder. I just noticed this from greg's mail. still waiting for his response about the proper solution for this patch. After that i will update version 2 for it. Your test is really efficient, thanks. Best regards, Dillon. On Mon, Apr 12, 2021 at 3:25 PM kernel test robot wrote: > > 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 > > 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@lists.01.org