On 12/04/22 at 11:47am, kernel test robot wrote: > Hi Baoquan, > > I love your patch! Perhaps something to improve: > > [auto build test WARNING on akpm-mm/mm-everything] > > url: https://github.com/intel-lab-lkp/linux/commits/Baoquan-He/mm-vmalloc-c-allow-vread-to-read-out-vm_map_ram-areas/20221204-093322 > base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything > patch link: https://lore.kernel.org/r/20221204013046.154960-4-bhe%40redhat.com > patch subject: [PATCH v1 3/7] mm/vmalloc.c: allow vread() to read out vm_map_ram areas > config: arm-randconfig-r046-20221204 > compiler: arm-linux-gnueabi-gcc (GCC) 12.1.0 > 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://github.com/intel-lab-lkp/linux/commit/0bcc4ce1e46418b86eb569175879081116649727 > git remote add linux-review https://github.com/intel-lab-lkp/linux > git fetch --no-tags linux-review Baoquan-He/mm-vmalloc-c-allow-vread-to-read-out-vm_map_ram-areas/20221204-093322 > git checkout 0bcc4ce1e46418b86eb569175879081116649727 > # save the config file > mkdir build_dir && cp config build_dir/.config > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash > > If you fix the issue, kindly add following tag where applicable > | Reported-by: kernel test robot <lkp@xxxxxxxxx> > > All warnings (new ones prefixed by >>): > > mm/vmalloc.c: In function 'vb_vread': > >> mm/vmalloc.c:3540:23: warning: variable 'offset' set but not used [-Wunused-but-set-variable] > 3540 | unsigned long offset; > | ^~~~~~ Thanks. The local variable 'offset' is needed, the handling in vb_vread() need be improved to cover the case in which reading is started from dirty or free regions. I will add below change to v2. diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 78cae59170d8..6612914459cf 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -3526,7 +3522,6 @@ static void vb_vread(char *buf, char *addr, int count) unsigned long offset; unsigned int rs, re, n; - offset = ((unsigned long)addr & (VMAP_BLOCK_SIZE - 1)) >> PAGE_SHIFT; vb = xa_load(&vmap_blocks, addr_to_vb_idx((unsigned long)addr)); spin_lock(&vb->lock); @@ -3547,16 +3542,22 @@ static void vb_vread(char *buf, char *addr, int count) addr++; count--; } - n = (re - rs + 1) << PAGE_SHIFT; + /*it could start reading from the middle of used region*/ + offset = offset_in_page(addr); + n = (re - rs + 1) << PAGE_SHIFT - offset; if (n > count) n = count; - aligned_vread(buf, start, n); + aligned_vread(buf, start+offset, n); buf += n; addr += n; count -= n; } spin_unlock(&vb->lock); + + /* zero-fill the left dirty or free regions */ + if (count) + memset(buf, 0, count); } /**
