Hi Chao, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 9cdbf6467424045617cd6e79dcaad06bb8efa31c commit: 093749e296e29a4b0162eb925a6701a01e8c9a98 f2fs: support age threshold based garbage collection date: 7 months ago config: powerpc-randconfig-r011-20210417 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project f549176ad976caa3e19edd036df9a7e12770af7c) 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 powerpc cross compiling tool for clang build # apt-get install binutils-powerpc-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 093749e296e29a4b0162eb925a6701a01e8c9a98 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=powerpc 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 >>): arch/powerpc/include/asm/io.h:601:3: note: expanded from macro 'DEF_PCI_AC_NORET' __do_##name al; \ ^~~~~~~~~~~~~~ <scratch space>:221:1: note: expanded from here __do_insw ^ arch/powerpc/include/asm/io.h:542:56: note: expanded from macro '__do_insw' #define __do_insw(p, b, n) readsw((PCI_IO_ADDR)_IO_BASE+(p), (b), (n)) ~~~~~~~~~~~~~~~~~~~~~^ In file included from fs/f2fs/gc.c:10: In file included from include/linux/backing-dev.h:15: In file included from include/linux/blkdev.h:13: In file included from include/linux/pagemap.h:11: In file included from include/linux/highmem.h:10: In file included from include/linux/hardirq.h:10: In file included from arch/powerpc/include/asm/hardirq.h:6: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/powerpc/include/asm/io.h:604: arch/powerpc/include/asm/io-defs.h:47:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] DEF_PCI_AC_NORET(insl, (unsigned long p, void *b, unsigned long c), ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/powerpc/include/asm/io.h:601:3: note: expanded from macro 'DEF_PCI_AC_NORET' __do_##name al; \ ^~~~~~~~~~~~~~ <scratch space>:223:1: note: expanded from here __do_insl ^ arch/powerpc/include/asm/io.h:543:56: note: expanded from macro '__do_insl' #define __do_insl(p, b, n) readsl((PCI_IO_ADDR)_IO_BASE+(p), (b), (n)) ~~~~~~~~~~~~~~~~~~~~~^ In file included from fs/f2fs/gc.c:10: In file included from include/linux/backing-dev.h:15: In file included from include/linux/blkdev.h:13: In file included from include/linux/pagemap.h:11: In file included from include/linux/highmem.h:10: In file included from include/linux/hardirq.h:10: In file included from arch/powerpc/include/asm/hardirq.h:6: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/powerpc/include/asm/io.h:604: arch/powerpc/include/asm/io-defs.h:49:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] DEF_PCI_AC_NORET(outsb, (unsigned long p, const void *b, unsigned long c), ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/powerpc/include/asm/io.h:601:3: note: expanded from macro 'DEF_PCI_AC_NORET' __do_##name al; \ ^~~~~~~~~~~~~~ <scratch space>:225:1: note: expanded from here __do_outsb ^ arch/powerpc/include/asm/io.h:544:58: note: expanded from macro '__do_outsb' #define __do_outsb(p, b, n) writesb((PCI_IO_ADDR)_IO_BASE+(p),(b),(n)) ~~~~~~~~~~~~~~~~~~~~~^ In file included from fs/f2fs/gc.c:10: In file included from include/linux/backing-dev.h:15: In file included from include/linux/blkdev.h:13: In file included from include/linux/pagemap.h:11: In file included from include/linux/highmem.h:10: In file included from include/linux/hardirq.h:10: In file included from arch/powerpc/include/asm/hardirq.h:6: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/powerpc/include/asm/io.h:604: arch/powerpc/include/asm/io-defs.h:51:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] DEF_PCI_AC_NORET(outsw, (unsigned long p, const void *b, unsigned long c), ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/powerpc/include/asm/io.h:601:3: note: expanded from macro 'DEF_PCI_AC_NORET' __do_##name al; \ ^~~~~~~~~~~~~~ <scratch space>:227:1: note: expanded from here __do_outsw ^ arch/powerpc/include/asm/io.h:545:58: note: expanded from macro '__do_outsw' #define __do_outsw(p, b, n) writesw((PCI_IO_ADDR)_IO_BASE+(p),(b),(n)) ~~~~~~~~~~~~~~~~~~~~~^ In file included from fs/f2fs/gc.c:10: In file included from include/linux/backing-dev.h:15: In file included from include/linux/blkdev.h:13: In file included from include/linux/pagemap.h:11: In file included from include/linux/highmem.h:10: In file included from include/linux/hardirq.h:10: In file included from arch/powerpc/include/asm/hardirq.h:6: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/powerpc/include/asm/io.h:604: arch/powerpc/include/asm/io-defs.h:53:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] DEF_PCI_AC_NORET(outsl, (unsigned long p, const void *b, unsigned long c), ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/powerpc/include/asm/io.h:601:3: note: expanded from macro 'DEF_PCI_AC_NORET' __do_##name al; \ ^~~~~~~~~~~~~~ <scratch space>:229:1: note: expanded from here __do_outsl ^ arch/powerpc/include/asm/io.h:546:58: note: expanded from macro '__do_outsl' #define __do_outsl(p, b, n) writesl((PCI_IO_ADDR)_IO_BASE+(p),(b),(n)) ~~~~~~~~~~~~~~~~~~~~~^ fs/f2fs/gc.c:1358:12: warning: stack frame size of 2160 bytes in function 'gc_data_segment' [-Wframe-larger-than=] static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, ^ static int get_victim_by_default(struct f2fs_sb_info *sbi, ^ 14 warnings generated. vim +/get_victim_by_default +622 fs/f2fs/gc.c 093749e296e29a Chao Yu 2020-08-04 613 0a8165d7c2cf13 Jaegeuk Kim 2012-11-29 614 /* 111d2495a8a8fb Masanari Iida 2013-03-19 615 * This function is called from two paths. 7bc0900347e069 Jaegeuk Kim 2012-11-02 616 * One is garbage collection and the other is SSR segment selection. 7bc0900347e069 Jaegeuk Kim 2012-11-02 617 * When it is called during GC, it just gets a victim segment 7bc0900347e069 Jaegeuk Kim 2012-11-02 618 * and it does not remove it from dirty seglist. 7bc0900347e069 Jaegeuk Kim 2012-11-02 619 * When it is called from SSR segment selection, it finds a segment 7bc0900347e069 Jaegeuk Kim 2012-11-02 620 * which has minimum valid blocks and removes it from dirty seglist. 7bc0900347e069 Jaegeuk Kim 2012-11-02 621 */ 7bc0900347e069 Jaegeuk Kim 2012-11-02 @622 static int get_victim_by_default(struct f2fs_sb_info *sbi, 093749e296e29a Chao Yu 2020-08-04 623 unsigned int *result, int gc_type, int type, 093749e296e29a Chao Yu 2020-08-04 624 char alloc_mode, unsigned long long age) 7bc0900347e069 Jaegeuk Kim 2012-11-02 625 { 7bc0900347e069 Jaegeuk Kim 2012-11-02 626 struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); e066b83c9b40f3 Jaegeuk Kim 2017-04-13 627 struct sit_info *sm = SIT_I(sbi); 7bc0900347e069 Jaegeuk Kim 2012-11-02 628 struct victim_sel_policy p; 3fa565039e3338 Sheng Yong 2016-09-29 629 unsigned int secno, last_victim; 04f0b2eaa3b3ee Qiuyang Sun 2019-06-05 630 unsigned int last_segment; 093749e296e29a Chao Yu 2020-08-04 631 unsigned int nsearched; 093749e296e29a Chao Yu 2020-08-04 632 bool is_atgc; 97767500781fae Qilong Zhang 2020-06-28 633 int ret = 0; 7bc0900347e069 Jaegeuk Kim 2012-11-02 634 210f41bc048263 Chao Yu 2014-09-15 635 mutex_lock(&dirty_i->seglist_lock); 04f0b2eaa3b3ee Qiuyang Sun 2019-06-05 636 last_segment = MAIN_SECS(sbi) * sbi->segs_per_sec; 210f41bc048263 Chao Yu 2014-09-15 637 7bc0900347e069 Jaegeuk Kim 2012-11-02 638 p.alloc_mode = alloc_mode; 093749e296e29a Chao Yu 2020-08-04 639 p.age = age; 093749e296e29a Chao Yu 2020-08-04 640 p.age_threshold = sbi->am.age_threshold; 7bc0900347e069 Jaegeuk Kim 2012-11-02 641 093749e296e29a Chao Yu 2020-08-04 642 retry: 093749e296e29a Chao Yu 2020-08-04 643 select_policy(sbi, gc_type, type, &p); 7bc0900347e069 Jaegeuk Kim 2012-11-02 644 p.min_segno = NULL_SEGNO; 093749e296e29a Chao Yu 2020-08-04 645 p.oldest_age = 0; 3fa565039e3338 Sheng Yong 2016-09-29 646 p.min_cost = get_max_cost(sbi, &p); 7bc0900347e069 Jaegeuk Kim 2012-11-02 647 093749e296e29a Chao Yu 2020-08-04 648 is_atgc = (p.gc_mode == GC_AT || p.alloc_mode == AT_SSR); 093749e296e29a Chao Yu 2020-08-04 649 nsearched = 0; 093749e296e29a Chao Yu 2020-08-04 650 093749e296e29a Chao Yu 2020-08-04 651 if (is_atgc) 093749e296e29a Chao Yu 2020-08-04 652 SIT_I(sbi)->dirty_min_mtime = ULLONG_MAX; 093749e296e29a Chao Yu 2020-08-04 653 e066b83c9b40f3 Jaegeuk Kim 2017-04-13 654 if (*result != NULL_SEGNO) { 97767500781fae Qilong Zhang 2020-06-28 655 if (!get_valid_blocks(sbi, *result, false)) { 97767500781fae Qilong Zhang 2020-06-28 656 ret = -ENODATA; 97767500781fae Qilong Zhang 2020-06-28 657 goto out; 97767500781fae Qilong Zhang 2020-06-28 658 } 97767500781fae Qilong Zhang 2020-06-28 659 97767500781fae Qilong Zhang 2020-06-28 660 if (sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result))) 97767500781fae Qilong Zhang 2020-06-28 661 ret = -EBUSY; 97767500781fae Qilong Zhang 2020-06-28 662 else e066b83c9b40f3 Jaegeuk Kim 2017-04-13 663 p.min_segno = *result; e066b83c9b40f3 Jaegeuk Kim 2017-04-13 664 goto out; e066b83c9b40f3 Jaegeuk Kim 2017-04-13 665 } e066b83c9b40f3 Jaegeuk Kim 2017-04-13 666 97767500781fae Qilong Zhang 2020-06-28 667 ret = -ENODATA; 3342bb303bf48d Chao Yu 2015-10-05 668 if (p.max_search == 0) 3342bb303bf48d Chao Yu 2015-10-05 669 goto out; 3342bb303bf48d Chao Yu 2015-10-05 670 e3080b0120a15e Chao Yu 2018-10-24 671 if (__is_large_section(sbi) && p.alloc_mode == LFS) { e3080b0120a15e Chao Yu 2018-10-24 672 if (sbi->next_victim_seg[BG_GC] != NULL_SEGNO) { e3080b0120a15e Chao Yu 2018-10-24 673 p.min_segno = sbi->next_victim_seg[BG_GC]; e3080b0120a15e Chao Yu 2018-10-24 674 *result = p.min_segno; e3080b0120a15e Chao Yu 2018-10-24 675 sbi->next_victim_seg[BG_GC] = NULL_SEGNO; e3080b0120a15e Chao Yu 2018-10-24 676 goto got_result; e3080b0120a15e Chao Yu 2018-10-24 677 } e3080b0120a15e Chao Yu 2018-10-24 678 if (gc_type == FG_GC && e3080b0120a15e Chao Yu 2018-10-24 679 sbi->next_victim_seg[FG_GC] != NULL_SEGNO) { e3080b0120a15e Chao Yu 2018-10-24 680 p.min_segno = sbi->next_victim_seg[FG_GC]; e3080b0120a15e Chao Yu 2018-10-24 681 *result = p.min_segno; e3080b0120a15e Chao Yu 2018-10-24 682 sbi->next_victim_seg[FG_GC] = NULL_SEGNO; e3080b0120a15e Chao Yu 2018-10-24 683 goto got_result; e3080b0120a15e Chao Yu 2018-10-24 684 } e3080b0120a15e Chao Yu 2018-10-24 685 } e3080b0120a15e Chao Yu 2018-10-24 686 e066b83c9b40f3 Jaegeuk Kim 2017-04-13 687 last_victim = sm->last_victim[p.gc_mode]; 7bc0900347e069 Jaegeuk Kim 2012-11-02 688 if (p.alloc_mode == LFS && gc_type == FG_GC) { 7bc0900347e069 Jaegeuk Kim 2012-11-02 689 p.min_segno = check_bg_victims(sbi); 7bc0900347e069 Jaegeuk Kim 2012-11-02 690 if (p.min_segno != NULL_SEGNO) 7bc0900347e069 Jaegeuk Kim 2012-11-02 691 goto got_it; 7bc0900347e069 Jaegeuk Kim 2012-11-02 692 } 7bc0900347e069 Jaegeuk Kim 2012-11-02 693 7bc0900347e069 Jaegeuk Kim 2012-11-02 694 while (1) { da52f8ade40b03 Jack Qiu 2020-06-18 695 unsigned long cost, *dirty_bitmap; da52f8ade40b03 Jack Qiu 2020-06-18 696 unsigned int unit_no, segno; da52f8ade40b03 Jack Qiu 2020-06-18 697 da52f8ade40b03 Jack Qiu 2020-06-18 698 dirty_bitmap = p.dirty_bitmap; da52f8ade40b03 Jack Qiu 2020-06-18 699 unit_no = find_next_bit(dirty_bitmap, da52f8ade40b03 Jack Qiu 2020-06-18 700 last_segment / p.ofs_unit, da52f8ade40b03 Jack Qiu 2020-06-18 701 p.offset / p.ofs_unit); da52f8ade40b03 Jack Qiu 2020-06-18 702 segno = unit_no * p.ofs_unit; a43f7ec327b0d8 Chao Yu 2015-10-05 703 if (segno >= last_segment) { e066b83c9b40f3 Jaegeuk Kim 2017-04-13 704 if (sm->last_victim[p.gc_mode]) { e066b83c9b40f3 Jaegeuk Kim 2017-04-13 705 last_segment = e066b83c9b40f3 Jaegeuk Kim 2017-04-13 706 sm->last_victim[p.gc_mode]; e066b83c9b40f3 Jaegeuk Kim 2017-04-13 707 sm->last_victim[p.gc_mode] = 0; 7bc0900347e069 Jaegeuk Kim 2012-11-02 708 p.offset = 0; 7bc0900347e069 Jaegeuk Kim 2012-11-02 709 continue; 7bc0900347e069 Jaegeuk Kim 2012-11-02 710 } 7bc0900347e069 Jaegeuk Kim 2012-11-02 711 break; 7bc0900347e069 Jaegeuk Kim 2012-11-02 712 } a57e564d14d9d1 Jin Xu 2013-09-13 713 a57e564d14d9d1 Jin Xu 2013-09-13 714 p.offset = segno + p.ofs_unit; 688159b6db47a9 Fan Li 2016-02-03 715 nsearched++; 688159b6db47a9 Fan Li 2016-02-03 716 :::::: The code at line 622 was first introduced by commit :::::: 7bc0900347e069a1676d28ad6f98cafaf8cfd6e9 f2fs: add garbage collection functions :::::: TO: Jaegeuk Kim <jaegeuk.kim(a)samsung.com&gt; :::::: CC: Jaegeuk Kim <jaegeuk.kim(a)samsung.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org