[kbuild-all] Re: [PATCH] mm/damon/dbgfs: add region_stat interface

Hi Xin, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on v5.15-rc5] [cannot apply to hnaz-mm/master next-20211012] [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/Xin-Hao/mm-damon-dbgfs-add-regio... base: 64570fbc14f8d7cb3fe3995f20e26bc25ce4b2cc config: arm64-randconfig-r014-20211012 (attached as .config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project c3dcf39554dbea780d6cb7e12239451ba47a2668) 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://github.com/0day-ci/linux/commit/256bdd48bd7719684cd8adbbda8a9df3d... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Xin-Hao/mm-damon-dbgfs-add-region_stat-interface/20211012-135023 git checkout 256bdd48bd7719684cd8adbbda8a9df3dc9c1008 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=arm64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): len += simple_read_from_buffer(buf, count, ppos, kbuf, written); ^~~ mm/damon/dbgfs.c:275:13: note: initialize the variable 'len' to silence this warning ssize_t len; ^ = 0 1 warning generated. vim +/len +311 mm/damon/dbgfs.c 268 269 static ssize_t dbgfs_region_stat_read(struct file *file, 270 char __user *buf, size_t count, loff_t *ppos) 271 { 272 struct damon_ctx *ctx = file->private_data; 273 struct damon_target *t; 274 char *kbuf; 275 ssize_t len; 276 int id, rc, written = 0; 277 278 kbuf = kmalloc(count, GFP_KERNEL); 279 if (!kbuf) 280 return -ENOMEM; 281 282 mutex_lock(&ctx->kdamond_lock); 283 damon_for_each_target(t, ctx) { 284 struct damon_region *r; 285 286 if (targetid_is_pid(ctx)) 287 id = (int)pid_vnr((struct pid *)t->id); 288 289 rc = scnprintf(&kbuf[written], count - written, 290 "last_aggregation=%lld.%lds\ntarget_id=%d\nnr_regions=%u\n", 291 ctx->last_aggregation.tv_sec, 292 ctx->last_aggregation.tv_nsec / 1000000, 293 id, t->nr_regions); 294 if (!rc) 295 goto out; 296 297 written += rc; 298 299 damon_for_each_region(r, t) { 300 rc = scnprintf(&kbuf[written], count - written, 301 "%lx-%lx(%lu KiB): %u\n", 302 r->ar.start, r->ar.end, 303 (r->ar.end - r->ar.start) >> 10, 304 r->nr_accesses); 305 if (!rc) 306 goto out; 307 308 written += rc; 309 } 310 312 } 313 314 out: 315 mutex_unlock(&ctx->kdamond_lock); 316 kfree(kbuf); 317 return len; 318 } 319 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org