tree: https://git.kernel.org/pub/scm/linux/kernel/git/sashal/linux-stable.git queue-4.9 head: 397027034d454e3ad94e49e88938860ee15d7de6 commit: 2d843653785d83e84dd658e7ca9643ae0a42aaa5 [100/170] serial: stm32: fix tx_empty condition config: nios2-allyesconfig (attached as .config) compiler: nios2-linux-gcc (GCC) 7.5.0 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 # https://git.kernel.org/pub/scm/linux/kernel/git/sashal/linux-stable.git/c... git remote add sashal-linux-stable https://git.kernel.org/pub/scm/linux/kernel/git/sashal/linux-stable.git git fetch --no-tags sashal-linux-stable queue-4.9 git checkout 2d843653785d83e84dd658e7ca9643ae0a42aaa5 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-7.5.0 make.cross W=1 ARCH=nios2 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): In file included from include/linux/err.h:4:0, from include/linux/clk.h:15, from drivers/tty/serial/stm32-usart.c:14: include/linux/scatterlist.h: In function 'sg_set_buf': arch/nios2/include/asm/page.h:90:33: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits] # define pfn_valid(pfn) ((pfn) >= ARCH_PFN_OFFSET && \ ^ include/linux/compiler.h:184:42: note: in definition of macro 'unlikely' # define unlikely(x) __builtin_expect(!!(x), 0) ^ include/linux/scatterlist.h:140:2: note: in expansion of macro 'BUG_ON' BUG_ON(!virt_addr_valid(buf)); ^~~~~~ arch/nios2/include/asm/page.h:94:33: note: in expansion of macro 'pfn_valid' # define virt_addr_valid(vaddr) pfn_valid(PFN_DOWN(virt_to_phys(vaddr))) ^~~~~~~~~ include/linux/scatterlist.h:140:10: note: in expansion of macro 'virt_addr_valid' BUG_ON(!virt_addr_valid(buf)); ^~~~~~~~~~~~~~~ include/linux/dma-mapping.h: In function 'dma_map_resource': arch/nios2/include/asm/page.h:90:33: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits] # define pfn_valid(pfn) ((pfn) >= ARCH_PFN_OFFSET && \ ^ include/linux/compiler.h:184:42: note: in definition of macro 'unlikely' # define unlikely(x) __builtin_expect(!!(x), 0) ^ include/linux/dma-mapping.h:284:2: note: in expansion of macro 'BUG_ON' BUG_ON(pfn_valid(PHYS_PFN(phys_addr))); ^~~~~~ include/linux/dma-mapping.h:284:9: note: in expansion of macro 'pfn_valid' BUG_ON(pfn_valid(PHYS_PFN(phys_addr))); ^~~~~~~~~ drivers/tty/serial/stm32-usart.c: In function 'stm32_tx_dma_complete': stm32_set_bits(port, ofs->icr, USART_CR_TC); ^~~~~~~~~~~ USART_SR_TC drivers/tty/serial/stm32-usart.c:180:34: note: each undeclared identifier is reported only once for each function it appears in drivers/tty/serial/stm32-usart.c: In function 'stm32_transmit_chars_dma': drivers/tty/serial/stm32-usart.c:223:15: warning: variable 'cookie' set but not used [-Wunused-but-set-variable] dma_cookie_t cookie; ^~~~~~ drivers/tty/serial/stm32-usart.c: In function 'stm32_of_dma_rx_probe': drivers/tty/serial/stm32-usart.c:736:15: warning: variable 'cookie' set but not used [-Wunused-but-set-variable] dma_cookie_t cookie; ^~~~~~ vim +180 drivers/tty/serial/stm32-usart.c 48a6092fb41fab Maxime Coquelin 2015-06-10 160 3489187204eb75 Alexandre TORGUE 2016-09-15 161 static void stm32_tx_dma_complete(void *arg) 3489187204eb75 Alexandre TORGUE 2016-09-15 162 { 3489187204eb75 Alexandre TORGUE 2016-09-15 163 struct uart_port *port = arg; 3489187204eb75 Alexandre TORGUE 2016-09-15 164 struct stm32_port *stm32port = to_stm32_port(port); 3489187204eb75 Alexandre TORGUE 2016-09-15 165 struct stm32_usart_offsets *ofs = &stm32port->info->ofs; 3489187204eb75 Alexandre TORGUE 2016-09-15 166 unsigned int isr; 3489187204eb75 Alexandre TORGUE 2016-09-15 167 int ret; 3489187204eb75 Alexandre TORGUE 2016-09-15 168 3489187204eb75 Alexandre TORGUE 2016-09-15 169 ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, 3489187204eb75 Alexandre TORGUE 2016-09-15 170 isr, 3489187204eb75 Alexandre TORGUE 2016-09-15 171 (isr & USART_SR_TC), 3489187204eb75 Alexandre TORGUE 2016-09-15 172 10, 100000); 3489187204eb75 Alexandre TORGUE 2016-09-15 173 3489187204eb75 Alexandre TORGUE 2016-09-15 174 if (ret) 3489187204eb75 Alexandre TORGUE 2016-09-15 175 dev_err(port->dev, "terminal count not set\n"); 3489187204eb75 Alexandre TORGUE 2016-09-15 176 3489187204eb75 Alexandre TORGUE 2016-09-15 177 if (ofs->icr == UNDEF_REG) 3489187204eb75 Alexandre TORGUE 2016-09-15 178 stm32_clr_bits(port, ofs->isr, USART_SR_TC); 3489187204eb75 Alexandre TORGUE 2016-09-15 179 else 3489187204eb75 Alexandre TORGUE 2016-09-15 @180 stm32_set_bits(port, ofs->icr, USART_CR_TC); 3489187204eb75 Alexandre TORGUE 2016-09-15 181 3489187204eb75 Alexandre TORGUE 2016-09-15 182 stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT); 3489187204eb75 Alexandre TORGUE 2016-09-15 183 stm32port->tx_dma_busy = false; 3489187204eb75 Alexandre TORGUE 2016-09-15 184 3489187204eb75 Alexandre TORGUE 2016-09-15 185 /* Let's see if we have pending data to send */ 3489187204eb75 Alexandre TORGUE 2016-09-15 186 stm32_transmit_chars(port); 3489187204eb75 Alexandre TORGUE 2016-09-15 187 } 3489187204eb75 Alexandre TORGUE 2016-09-15 188 :::::: The code at line 180 was first introduced by commit :::::: 3489187204eb75e5635d8836babfd0a18be613f4 serial: stm32: adding dma support :::::: TO: Alexandre TORGUE <alexandre.torgue(a)st.com&gt; :::::: CC: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org