Hi xinhui, https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/xinhui-pan/drm-Optimise-for-continuous-memory-allocation/20221218-145922 base: git://anongit.freedesktop.org/drm/drm-misc drm-misc-next patch link: https://lore.kernel.org/r/20221218065708.93332-1-xinhui.pan%40amd.com patch subject: [PATCH v6] drm: Optimise for continuous memory allocation config: s390-randconfig-m041-20221218 compiler: s390-linux-gcc (GCC) 12.1.0 If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot <lkp@xxxxxxxxx> | Reported-by: Dan Carpenter <error27@xxxxxxxxx> smatch warnings: drivers/gpu/drm/drm_buddy.c:501 find_continuous_blocks() error: uninitialized symbol 'block'. vim +/block +501 drivers/gpu/drm/drm_buddy.c 8a257b57bc11a2 xinhui pan 2022-12-18 472 static struct drm_buddy_block * 8a257b57bc11a2 xinhui pan 2022-12-18 473 find_continuous_blocks(struct drm_buddy *mm, 8a257b57bc11a2 xinhui pan 2022-12-18 474 int order, 8a257b57bc11a2 xinhui pan 2022-12-18 475 unsigned long flags, 8a257b57bc11a2 xinhui pan 2022-12-18 476 struct drm_buddy_block **lb) 8a257b57bc11a2 xinhui pan 2022-12-18 477 { 8a257b57bc11a2 xinhui pan 2022-12-18 478 struct list_head *head = &mm->free_list[order - 1]; 8a257b57bc11a2 xinhui pan 2022-12-18 479 struct drm_buddy_block *free_block, *first = NULL, *last = NULL; 8a257b57bc11a2 xinhui pan 2022-12-18 480 8a257b57bc11a2 xinhui pan 2022-12-18 481 /* 8a257b57bc11a2 xinhui pan 2022-12-18 482 * Look for continuous free memory in buddy and buddy-in-law. 8a257b57bc11a2 xinhui pan 2022-12-18 483 * IOW, the most left blocks at right of free block and the most right 8a257b57bc11a2 xinhui pan 2022-12-18 484 * blocks at left of free block. 8a257b57bc11a2 xinhui pan 2022-12-18 485 */ 8a257b57bc11a2 xinhui pan 2022-12-18 486 8a257b57bc11a2 xinhui pan 2022-12-18 487 list_for_each_entry(free_block, head, link) { 8a257b57bc11a2 xinhui pan 2022-12-18 488 struct drm_buddy_block *buddy, *parent, *block; 8a257b57bc11a2 xinhui pan 2022-12-18 489 int left, min_order = 0; 8a257b57bc11a2 xinhui pan 2022-12-18 490 LIST_HEAD(fbl); 8a257b57bc11a2 xinhui pan 2022-12-18 491 8a257b57bc11a2 xinhui pan 2022-12-18 492 parent = free_block->parent; 8a257b57bc11a2 xinhui pan 2022-12-18 493 if (!parent) 8a257b57bc11a2 xinhui pan 2022-12-18 494 continue; 8a257b57bc11a2 xinhui pan 2022-12-18 495 8a257b57bc11a2 xinhui pan 2022-12-18 496 left = parent->left == free_block; 8a257b57bc11a2 xinhui pan 2022-12-18 497 list_add(&free_block->tmp_link, &fbl); 8a257b57bc11a2 xinhui pan 2022-12-18 498 buddy = __get_buddy(free_block); 8a257b57bc11a2 xinhui pan 2022-12-18 499 __continuous_block_in_tree(buddy, &fbl, left, min_order); 8a257b57bc11a2 xinhui pan 2022-12-18 500 8a257b57bc11a2 xinhui pan 2022-12-18 @501 while (parent && !((parent->left == block) ^ left)) { ^^^^^ Not initialized on first iteration. 8a257b57bc11a2 xinhui pan 2022-12-18 502 block = parent; 8a257b57bc11a2 xinhui pan 2022-12-18 503 parent = parent->parent; 8a257b57bc11a2 xinhui pan 2022-12-18 504 } 8a257b57bc11a2 xinhui pan 2022-12-18 505 8a257b57bc11a2 xinhui pan 2022-12-18 506 if (!parent) 8a257b57bc11a2 xinhui pan 2022-12-18 507 continue; 8a257b57bc11a2 xinhui pan 2022-12-18 508 8a257b57bc11a2 xinhui pan 2022-12-18 509 buddy = __get_buddy(block); 8a257b57bc11a2 xinhui pan 2022-12-18 510 __continuous_block_in_tree(buddy, &fbl, !left, min_order); 8a257b57bc11a2 xinhui pan 2022-12-18 511 8a257b57bc11a2 xinhui pan 2022-12-18 512 /* list head of fbl is invalid outside. 8a257b57bc11a2 xinhui pan 2022-12-18 513 * Walk through list from first fo last only. 8a257b57bc11a2 xinhui pan 2022-12-18 514 */ 8a257b57bc11a2 xinhui pan 2022-12-18 515 if (__free_block_in_order(&fbl, free_block, order, &first, &last)) 8a257b57bc11a2 xinhui pan 2022-12-18 516 break; 8a257b57bc11a2 xinhui pan 2022-12-18 517 } 8a257b57bc11a2 xinhui pan 2022-12-18 518 8a257b57bc11a2 xinhui pan 2022-12-18 519 *lb = last; 8a257b57bc11a2 xinhui pan 2022-12-18 520 return first; 8a257b57bc11a2 xinhui pan 2022-12-18 521 } -- 0-DAY CI Kernel Test Service https://01.org/lkp
