Re: [kbuild-all] Re: fs/f2fs/gc.c:622:12: warning: stack frame size of 3056 bytes in function 'get_victim_by_default'

[Rong Chen <rong.a.chen@intel.com>]

On 1/11/21 4:23 PM, Chao Yu wrote:
> Hello,
>
> Thanks for the report.
>
> I replied for your previous report [1], could you please check that?
>
> [1] 
> https://lore.kernel.org/lkml/8a8ef6b8-84c2-abfe-e758-2fa52a989c72@huawei.com/
>
> That says, in my environment, get_victim_by_default()'s frame size is 
> less than
> 512 bytes, and also after going through related code, I don't see any 
> obvious
> large stack size usage.
>
> Is that issue a powerpc specified issue?

Hi Chao,

The issue can be found on arch mips too:

fs/f2fs/gc.c:622:12: warning: stack frame size of 1672 bytes in function 'get_victim_by_default' [-Wframe-larger-than=]

    static int get_victim_by_default(struct f2fs_sb_info *sbi,
               ^
    1 warning generated.



>
> Could you help to verify powerpc compiling with 
> -Wframe-larger-than=512 after
> reverting that atgc patch? I mean whether get_victim_by_default() 
> already have
> large frame size before applying atgc patch (commit 093749e296e2)?

After reverting commit 093749e29 and set -Wframe-larger-than=512, the 
warning is

fs/f2fs/gc.c:325:12: warning: stack frame size of 912 bytes in function 
'get_victim_by_default' [-Wframe-larger-than=]
static int get_victim_by_default(struct f2fs_sb_info *sbi,

Best Regards,
Rong Chen

>
> On 2021/1/9 21:18, kernel test robot wrote:
>> 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
>>
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