Hi Chao,

FYI, the error/warning still remains.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   996e435fd401de35df62ac943ab9402cfe85c430
commit: 093749e296e29a4b0162eb925a6701a01e8c9a98 f2fs: support age threshold based garbage collection
date:   4 months ago
config: powerpc-randconfig-r033-20210109 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project bc556e5685c0f97e79fb7b3c6f15cc5062db8e36)
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/?id=093749e296e29a4b0162eb925a6701a01e8c9a98
        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 ARCH=powerpc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   arch/powerpc/include/asm/io-defs.h:45:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(insw, (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>:182:1: 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>:184:1: 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>:186:1: 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>:188:1: 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>:190:1: 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:622:12: warning: stack frame size of 3056 bytes in function 'get_victim_by_default' [-Wframe-larger-than=]
   static int get_victim_by_default(struct f2fs_sb_info *sbi,
              ^
   13 warnings generated.


vim +/get_victim_by_default +622 fs/f2fs/gc.c

093749e296e29a4 Chao Yu       2020-08-04  613  
0a8165d7c2cf139 Jaegeuk Kim   2012-11-29  614  /*
111d2495a8a8fbd Masanari Iida 2013-03-19  615   * This function is called from two paths.
7bc0900347e069a Jaegeuk Kim   2012-11-02  616   * One is garbage collection and the other is SSR segment selection.
7bc0900347e069a Jaegeuk Kim   2012-11-02  617   * When it is called during GC, it just gets a victim segment
7bc0900347e069a Jaegeuk Kim   2012-11-02  618   * and it does not remove it from dirty seglist.
7bc0900347e069a Jaegeuk Kim   2012-11-02  619   * When it is called from SSR segment selection, it finds a segment
7bc0900347e069a Jaegeuk Kim   2012-11-02  620   * which has minimum valid blocks and removes it from dirty seglist.
7bc0900347e069a Jaegeuk Kim   2012-11-02  621   */
7bc0900347e069a Jaegeuk Kim   2012-11-02 @622  static int get_victim_by_default(struct f2fs_sb_info *sbi,
093749e296e29a4 Chao Yu       2020-08-04  623  			unsigned int *result, int gc_type, int type,
093749e296e29a4 Chao Yu       2020-08-04  624  			char alloc_mode, unsigned long long age)
7bc0900347e069a Jaegeuk Kim   2012-11-02  625  {
7bc0900347e069a Jaegeuk Kim   2012-11-02  626  	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
e066b83c9b40f3a Jaegeuk Kim   2017-04-13  627  	struct sit_info *sm = SIT_I(sbi);
7bc0900347e069a Jaegeuk Kim   2012-11-02  628  	struct victim_sel_policy p;
3fa565039e3338f Sheng Yong    2016-09-29  629  	unsigned int secno, last_victim;
04f0b2eaa3b3ee2 Qiuyang Sun   2019-06-05  630  	unsigned int last_segment;
093749e296e29a4 Chao Yu       2020-08-04  631  	unsigned int nsearched;
093749e296e29a4 Chao Yu       2020-08-04  632  	bool is_atgc;
97767500781fae9 Qilong Zhang  2020-06-28  633  	int ret = 0;
7bc0900347e069a Jaegeuk Kim   2012-11-02  634  
210f41bc048263d Chao Yu       2014-09-15  635  	mutex_lock(&dirty_i->seglist_lock);
04f0b2eaa3b3ee2 Qiuyang Sun   2019-06-05  636  	last_segment = MAIN_SECS(sbi) * sbi->segs_per_sec;
210f41bc048263d Chao Yu       2014-09-15  637  
7bc0900347e069a Jaegeuk Kim   2012-11-02  638  	p.alloc_mode = alloc_mode;
093749e296e29a4 Chao Yu       2020-08-04  639  	p.age = age;
093749e296e29a4 Chao Yu       2020-08-04  640  	p.age_threshold = sbi->am.age_threshold;
7bc0900347e069a Jaegeuk Kim   2012-11-02  641  
093749e296e29a4 Chao Yu       2020-08-04  642  retry:
093749e296e29a4 Chao Yu       2020-08-04  643  	select_policy(sbi, gc_type, type, &p);
7bc0900347e069a Jaegeuk Kim   2012-11-02  644  	p.min_segno = NULL_SEGNO;
093749e296e29a4 Chao Yu       2020-08-04  645  	p.oldest_age = 0;
3fa565039e3338f Sheng Yong    2016-09-29  646  	p.min_cost = get_max_cost(sbi, &p);
7bc0900347e069a Jaegeuk Kim   2012-11-02  647  
093749e296e29a4 Chao Yu       2020-08-04  648  	is_atgc = (p.gc_mode == GC_AT || p.alloc_mode == AT_SSR);
093749e296e29a4 Chao Yu       2020-08-04  649  	nsearched = 0;
093749e296e29a4 Chao Yu       2020-08-04  650  
093749e296e29a4 Chao Yu       2020-08-04  651  	if (is_atgc)
093749e296e29a4 Chao Yu       2020-08-04  652  		SIT_I(sbi)->dirty_min_mtime = ULLONG_MAX;
093749e296e29a4 Chao Yu       2020-08-04  653  
e066b83c9b40f3a Jaegeuk Kim   2017-04-13  654  	if (*result != NULL_SEGNO) {
97767500781fae9 Qilong Zhang  2020-06-28  655  		if (!get_valid_blocks(sbi, *result, false)) {
97767500781fae9 Qilong Zhang  2020-06-28  656  			ret = -ENODATA;
97767500781fae9 Qilong Zhang  2020-06-28  657  			goto out;
97767500781fae9 Qilong Zhang  2020-06-28  658  		}
97767500781fae9 Qilong Zhang  2020-06-28  659  
97767500781fae9 Qilong Zhang  2020-06-28  660  		if (sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
97767500781fae9 Qilong Zhang  2020-06-28  661  			ret = -EBUSY;
97767500781fae9 Qilong Zhang  2020-06-28  662  		else
e066b83c9b40f3a Jaegeuk Kim   2017-04-13  663  			p.min_segno = *result;
e066b83c9b40f3a Jaegeuk Kim   2017-04-13  664  		goto out;
e066b83c9b40f3a Jaegeuk Kim   2017-04-13  665  	}
e066b83c9b40f3a Jaegeuk Kim   2017-04-13  666  
97767500781fae9 Qilong Zhang  2020-06-28  667  	ret = -ENODATA;
3342bb303bf48dd Chao Yu       2015-10-05  668  	if (p.max_search == 0)
3342bb303bf48dd Chao Yu       2015-10-05  669  		goto out;
3342bb303bf48dd Chao Yu       2015-10-05  670  
e3080b0120a15e6 Chao Yu       2018-10-24  671  	if (__is_large_section(sbi) && p.alloc_mode == LFS) {
e3080b0120a15e6 Chao Yu       2018-10-24  672  		if (sbi->next_victim_seg[BG_GC] != NULL_SEGNO) {
e3080b0120a15e6 Chao Yu       2018-10-24  673  			p.min_segno = sbi->next_victim_seg[BG_GC];
e3080b0120a15e6 Chao Yu       2018-10-24  674  			*result = p.min_segno;
e3080b0120a15e6 Chao Yu       2018-10-24  675  			sbi->next_victim_seg[BG_GC] = NULL_SEGNO;
e3080b0120a15e6 Chao Yu       2018-10-24  676  			goto got_result;
e3080b0120a15e6 Chao Yu       2018-10-24  677  		}
e3080b0120a15e6 Chao Yu       2018-10-24  678  		if (gc_type == FG_GC &&
e3080b0120a15e6 Chao Yu       2018-10-24  679  				sbi->next_victim_seg[FG_GC] != NULL_SEGNO) {
e3080b0120a15e6 Chao Yu       2018-10-24  680  			p.min_segno = sbi->next_victim_seg[FG_GC];
e3080b0120a15e6 Chao Yu       2018-10-24  681  			*result = p.min_segno;
e3080b0120a15e6 Chao Yu       2018-10-24  682  			sbi->next_victim_seg[FG_GC] = NULL_SEGNO;
e3080b0120a15e6 Chao Yu       2018-10-24  683  			goto got_result;
e3080b0120a15e6 Chao Yu       2018-10-24  684  		}
e3080b0120a15e6 Chao Yu       2018-10-24  685  	}
e3080b0120a15e6 Chao Yu       2018-10-24  686  
e066b83c9b40f3a Jaegeuk Kim   2017-04-13  687  	last_victim = sm->last_victim[p.gc_mode];
7bc0900347e069a Jaegeuk Kim   2012-11-02  688  	if (p.alloc_mode == LFS && gc_type == FG_GC) {
7bc0900347e069a Jaegeuk Kim   2012-11-02  689  		p.min_segno = check_bg_victims(sbi);
7bc0900347e069a Jaegeuk Kim   2012-11-02  690  		if (p.min_segno != NULL_SEGNO)
7bc0900347e069a Jaegeuk Kim   2012-11-02  691  			goto got_it;
7bc0900347e069a Jaegeuk Kim   2012-11-02  692  	}
7bc0900347e069a Jaegeuk Kim   2012-11-02  693  
7bc0900347e069a Jaegeuk Kim   2012-11-02  694  	while (1) {
da52f8ade40b032 Jack Qiu      2020-06-18  695  		unsigned long cost, *dirty_bitmap;
da52f8ade40b032 Jack Qiu      2020-06-18  696  		unsigned int unit_no, segno;
da52f8ade40b032 Jack Qiu      2020-06-18  697  
da52f8ade40b032 Jack Qiu      2020-06-18  698  		dirty_bitmap = p.dirty_bitmap;
da52f8ade40b032 Jack Qiu      2020-06-18  699  		unit_no = find_next_bit(dirty_bitmap,
da52f8ade40b032 Jack Qiu      2020-06-18  700  				last_segment / p.ofs_unit,
da52f8ade40b032 Jack Qiu      2020-06-18  701  				p.offset / p.ofs_unit);
da52f8ade40b032 Jack Qiu      2020-06-18  702  		segno = unit_no * p.ofs_unit;
a43f7ec327b0d86 Chao Yu       2015-10-05  703  		if (segno >= last_segment) {
e066b83c9b40f3a Jaegeuk Kim   2017-04-13  704  			if (sm->last_victim[p.gc_mode]) {
e066b83c9b40f3a Jaegeuk Kim   2017-04-13  705  				last_segment =
e066b83c9b40f3a Jaegeuk Kim   2017-04-13  706  					sm->last_victim[p.gc_mode];
e066b83c9b40f3a Jaegeuk Kim   2017-04-13  707  				sm->last_victim[p.gc_mode] = 0;
7bc0900347e069a Jaegeuk Kim   2012-11-02  708  				p.offset = 0;
7bc0900347e069a Jaegeuk Kim   2012-11-02  709  				continue;
7bc0900347e069a Jaegeuk Kim   2012-11-02  710  			}
7bc0900347e069a Jaegeuk Kim   2012-11-02  711  			break;
7bc0900347e069a Jaegeuk Kim   2012-11-02  712  		}
a57e564d14d9d12 Jin Xu        2013-09-13  713  
a57e564d14d9d12 Jin Xu        2013-09-13  714  		p.offset = segno + p.ofs_unit;
688159b6db47a9e Fan Li        2016-02-03  715  		nsearched++;
688159b6db47a9e 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@samsung.com>
:::::: CC: Jaegeuk Kim <jaegeuk.kim@samsung.com>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org