tree: https://github.com/ammarfaizi2/linux-block dhowells/linux-fs/netfs-maple head: 429e2bb6fb190f390ed23afc0d2308e877c43be5 commit: e9340673baaf1ff587aed3391aa411cf554bc42e [34/35] netfs: Slice a writeback from a dirty region config: sparc-randconfig-s031-20220210 (https://download.01.org/0day-ci/archive/20220212/202202120413.rYahW6Tp-lk...) compiler: sparc-linux-gcc (GCC) 11.2.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # apt-get install sparse # sparse version: v0.6.4-dirty # https://github.com/ammarfaizi2/linux-block/commit/e9340673baaf1ff587aed33... git remote add ammarfaizi2-block https://github.com/ammarfaizi2/linux-block git fetch --no-tags ammarfaizi2-block dhowells/linux-fs/netfs-maple git checkout e9340673baaf1ff587aed3391aa411cf554bc42e # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=sparc SHELL=/bin/bash fs/netfs/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; sparse warnings: (new ones prefixed by >>) fs/netfs/flush.c:448:48: sparse: sparse: Using plain integer as NULL pointer vim +400 fs/netfs/flush.c 293 294 /* 295 * Flush some of the dirty queue, transforming a part of a sequence of dirty 296 * regions into a block we can flush. 297 * 298 * A number of things constrain us: 299 * - The region we write out should not be undergoing modification 300 * - We may need to expand or split the region for a number of reasons: 301 * - Filesystem storage block/object size 302 * - Filesystem RPC size (wsize) 303 * - Cache block size 304 * - Cache DIO block size 305 * - Crypto/compression block size 306 * 307 * This may be entered multiple times simultaneously. Automatic flushing by 308 * the VM is serialised on I_SYNC, but things like fsync() may enter multiple 309 * times simultaneously. 310 */ 311 static int netfs_flush_dirty(struct netfs_writeback *wback, 312 struct writeback_control *wbc, 313 struct netfs_i_context *ctx, 314 struct ma_state *mas, 315 pgoff_t *_first, pgoff_t last, 316 struct netfs_dirty_region *spares[2]) 317 { 318 struct netfs_dirty_region *region; 319 struct folio *folio; 320 pgoff_t first = *_first; 321 pgoff_t csize = 1UL << ctx->cache_order; 322 long ret; 323 324 XA_STATE(xas, &wback->mapping->i_pages, 0); 325 326 /* Round out the range we're looking through to accommodate whole cache 327 * blocks. The cache may only be able to store blocks of that size, in 328 * which case we may need to add non-dirty pages to the buffer too. 329 */ 330 if (ctx->cache_order) { 331 first = round_down(first, csize); 332 last = round_up_incl(last, csize); 333 } 334 335 _enter("%lx-%lx", first, last); 336 337 rcu_read_lock(); 338 mtree_lock(&ctx->dirty_regions); 339 340 /* Find the first dirty region that overlaps the requested range */ 341 mas_set(mas, first); 342 do { 343 region = mas_find(mas, last); 344 if (!region) 345 goto found_nothing; 346 } while (netfs_mas_is_flushing(region)); 347 348 _debug("query D=%x %lx-%lx", 349 netfs_mas_is_valid(region) ? region->debug_id : 0, 350 mas->index, mas->last); 351 352 wback->first = max(mas->index, first); 353 if (wback->first > 0) { 354 _debug("nonz %lx", wback->first); 355 356 /* The first folio might extend backwards beyond the start of 357 * the proposed region - in which case we need to include that 358 * also. But at least, in such a case, the folio size has to 359 * be an integer multiple of the cache blocksize. 360 */ 361 if (mas->index < wback->first) { 362 _debug("check folio %lx", wback->first); 363 xas_set(&xas, wback->first); 364 do { 365 xas_reset(&xas); 366 folio = xas_load(&xas); 367 } while (xas_retry(&xas, folio)); 368 369 if (folio && !xa_is_value(folio)) { 370 _debug("check folio %lx", folio->index); 371 /* A region span *should not* end in the middle of a folio. */ 372 BUG_ON(folio->index < mas->index); 373 if (folio->index < wback->first) { 374 wback->first = folio->index; 375 mas_set_range(mas, wback->first, mas->last); 376 } 377 } 378 } 379 380 _debug("fol %lx", wback->first); 381 382 if (mas->index < wback->first) { 383 pgoff_t saved_last = mas->last; 384 _debug("splitf %lx-%lx %lx", mas->index, mas->last, first); 385 netfs_split_off_front(ctx, mas, region, &spares[0], first - 1, 386 netfs_dirty_trace_split_off_front); 387 mas_set_range(mas, first, saved_last); 388 } 389 390 wback->last = mas->last; 391 } 392 393 while (mas->last < last) { 394 _debug("store %lx-%lx", mas->index, mas->last); 395 wback->last = mas->last; 396 mas_store(mas, netfs_mas_set_flushing(region)); 397 if (region != NETFS_COPY_TO_CACHE) { 398 netfs_get_dirty_region(ctx, region, netfs_region_trace_get_wback); 399 list_add_tail(&region->flush_link, &wback->regions); 401 netfs_dirty_trace_flush); 402 } 403 404 region = mas_next(mas, mas->last + 1); 405 if (!region || netfs_mas_is_flushing(region)) 406 goto no_more; 407 if (mas->last >= last) 408 break; 409 _debug("query+ D=%x %lx-%lx", 410 netfs_mas_is_valid(region) ? region->debug_id : 0, 411 mas->index, mas->last); 412 } 413 414 /* Deal with the region we're looking at exceeding the specified range. 415 * In such a case, we need to split the region - and the last folio may 416 * extend beyond the end of the proposed region - in which case we need 417 * to include that also. And, again, the folio size has to be an 418 * integer multiple of the cache blocksize. 419 */ 420 if (mas->last > last) { 421 xas_set(&xas, last); 422 do { 423 xas_reset(&xas); 424 folio = xas_load(&xas); 425 } while (xas_retry(&xas, folio)); 426 427 if (folio && !xa_is_value(folio)) { 428 pgoff_t flast = folio_next_index(folio) - 1; 429 430 _debug("flast %lx %lx %lx", flast, mas->last, last); 431 /* A region span *should not* end in the middle of a folio. */ 432 BUG_ON(flast > mas->last); 433 if (flast > last) { 434 last = flast; 435 mas_set_range(mas, mas->index, last); 436 } 437 } 438 439 region = netfs_split_off_front(ctx, mas, region, &spares[1], last, 440 netfs_dirty_trace_split_off_back); 441 } 442 443 wback->last = mas->last; 444 mas_store(mas, netfs_mas_set_flushing(region)); 445 if (region != NETFS_COPY_TO_CACHE) { 446 netfs_get_dirty_region(ctx, region, netfs_region_trace_get_wback); 447 list_add_tail(&region->flush_link, &wback->regions); 448 trace_netfs_dirty(ctx, region, 0, mas->index, mas->last, 449 netfs_dirty_trace_flush2); 450 } 451 452 no_more: 453 /* We've now got a contiguous span. Some of the subspans may only need 454 * writing to the cache, whilst others need writing to both the server 455 * and the cache. 456 */ 457 _debug("span %lx-%lx", wback->first, wback->last); 458 *_first = last + 1; 459 mtree_unlock(&ctx->dirty_regions); 460 rcu_read_unlock(); 461 462 /* Load the pages into the raw-data buffer and transition them over to 463 * the writeback state. 464 */ 465 ret = netfs_flush_get_pages(wback, ctx); 466 if (ret < 0) 467 goto undo; 468 469 netfs_writeback_lock(wback); 470 netfs_writeback_start(wback); 471 trace_netfs_wback(wback); 472 473 wbc->nr_to_write -= wback->last - wback->first + 1; 474 *_first = wback->last + 1; 475 _leave(" = %lx [%lx]", wback->last - wback->first + 1, *_first); 476 return 1; 477 478 found_nothing: 479 *_first = last + 1; 480 mtree_unlock(&ctx->dirty_regions); 481 rcu_read_unlock(); 482 return 0; 483 484 undo: 485 BUG(); // TODO 486 } 487 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org