Hi Wolfgang, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on linux/master] url: https://github.com/0day-ci/linux/commits/Wolfgang-Bumiller/blk-cgroup-alw... base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 136057256686de39cc3a07c2e39ef6bc43003ff6 config: um-i386_defconfig (https://download.01.org/0day-ci/archive/20220110/202201102157.vMQdZCc7-lk...) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://github.com/0day-ci/linux/commit/c3b02ad1d968fc1f962c4e9438ebcd221... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Wolfgang-Bumiller/blk-cgroup-always-terminate-io-stat-lines/20220110-183914 git checkout c3b02ad1d968fc1f962c4e9438ebcd22140c3403 # save the config file to linux build tree mkdir build_dir make W=1 O=build_dir ARCH=um SUBARCH=i386 SHELL=/bin/bash 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 >>): block/blk-cgroup.c: In function 'blkcg_print_one_stat': 891 | bool has_stats = false; | ^~~~~~~~~ vim +/has_stats +891 block/blk-cgroup.c ef45fe470e1e54 Boris Burkov 2020-06-01 886 49cb5168a7c6ab Christoph Hellwig 2021-08-10 887 static void blkcg_print_one_stat(struct blkcg_gq *blkg, struct seq_file *s) 2ee867dcfa2eae Tejun Heo 2015-08-18 888 { f73316482977ac Tejun Heo 2019-11-07 889 struct blkg_iostat_set *bis = &blkg->iostat; 636620b66d5d40 Tejun Heo 2018-07-18 890 u64 rbytes, wbytes, rios, wios, dbytes, dios; 903d23f0a354f2 Josef Bacik 2018-07-03 @891 bool has_stats = false; 49cb5168a7c6ab Christoph Hellwig 2021-08-10 892 const char *dname; f73316482977ac Tejun Heo 2019-11-07 893 unsigned seq; 49cb5168a7c6ab Christoph Hellwig 2021-08-10 894 int i; b0814361a25cba Tejun Heo 2019-11-05 895 b0814361a25cba Tejun Heo 2019-11-05 896 if (!blkg->online) 49cb5168a7c6ab Christoph Hellwig 2021-08-10 897 return; b0814361a25cba Tejun Heo 2019-11-05 898 2ee867dcfa2eae Tejun Heo 2015-08-18 899 dname = blkg_dev_name(blkg); 2ee867dcfa2eae Tejun Heo 2015-08-18 900 if (!dname) 49cb5168a7c6ab Christoph Hellwig 2021-08-10 901 return; 2ee867dcfa2eae Tejun Heo 2015-08-18 902 252c651a4c854b Christoph Hellwig 2021-08-10 903 seq_printf(s, "%s ", dname); 903d23f0a354f2 Josef Bacik 2018-07-03 904 f73316482977ac Tejun Heo 2019-11-07 905 do { f73316482977ac Tejun Heo 2019-11-07 906 seq = u64_stats_fetch_begin(&bis->sync); 2ee867dcfa2eae Tejun Heo 2015-08-18 907 f73316482977ac Tejun Heo 2019-11-07 908 rbytes = bis->cur.bytes[BLKG_IOSTAT_READ]; f73316482977ac Tejun Heo 2019-11-07 909 wbytes = bis->cur.bytes[BLKG_IOSTAT_WRITE]; f73316482977ac Tejun Heo 2019-11-07 910 dbytes = bis->cur.bytes[BLKG_IOSTAT_DISCARD]; f73316482977ac Tejun Heo 2019-11-07 911 rios = bis->cur.ios[BLKG_IOSTAT_READ]; f73316482977ac Tejun Heo 2019-11-07 912 wios = bis->cur.ios[BLKG_IOSTAT_WRITE]; f73316482977ac Tejun Heo 2019-11-07 913 dios = bis->cur.ios[BLKG_IOSTAT_DISCARD]; f73316482977ac Tejun Heo 2019-11-07 914 } while (u64_stats_fetch_retry(&bis->sync, seq)); 2ee867dcfa2eae Tejun Heo 2015-08-18 915 903d23f0a354f2 Josef Bacik 2018-07-03 916 if (rbytes || wbytes || rios || wios) { 903d23f0a354f2 Josef Bacik 2018-07-03 917 has_stats = true; 252c651a4c854b Christoph Hellwig 2021-08-10 918 seq_printf(s, "rbytes=%llu wbytes=%llu rios=%llu wios=%llu dbytes=%llu dios=%llu", 636620b66d5d40 Tejun Heo 2018-07-18 919 rbytes, wbytes, rios, wios, 636620b66d5d40 Tejun Heo 2018-07-18 920 dbytes, dios); 903d23f0a354f2 Josef Bacik 2018-07-03 921 } 903d23f0a354f2 Josef Bacik 2018-07-03 922 07b0fdecb24773 Tejun Heo 2019-07-16 923 if (blkcg_debug_stats && atomic_read(&blkg->use_delay)) { d09d8df3a29403 Josef Bacik 2018-07-03 924 has_stats = true; 252c651a4c854b Christoph Hellwig 2021-08-10 925 seq_printf(s, " use_delay=%d delay_nsec=%llu", d09d8df3a29403 Josef Bacik 2018-07-03 926 atomic_read(&blkg->use_delay), 49cb5168a7c6ab Christoph Hellwig 2021-08-10 927 atomic64_read(&blkg->delay_nsec)); d09d8df3a29403 Josef Bacik 2018-07-03 928 } d09d8df3a29403 Josef Bacik 2018-07-03 929 903d23f0a354f2 Josef Bacik 2018-07-03 930 for (i = 0; i < BLKCG_MAX_POLS; i++) { 903d23f0a354f2 Josef Bacik 2018-07-03 931 struct blkcg_policy *pol = blkcg_policy[i]; 903d23f0a354f2 Josef Bacik 2018-07-03 932 903d23f0a354f2 Josef Bacik 2018-07-03 933 if (!blkg->pd[i] || !pol->pd_stat_fn) 903d23f0a354f2 Josef Bacik 2018-07-03 934 continue; 903d23f0a354f2 Josef Bacik 2018-07-03 935 252c651a4c854b Christoph Hellwig 2021-08-10 936 if (pol->pd_stat_fn(blkg->pd[i], s)) 903d23f0a354f2 Josef Bacik 2018-07-03 937 has_stats = true; 903d23f0a354f2 Josef Bacik 2018-07-03 938 } 07b0fdecb24773 Tejun Heo 2019-07-16 939 c3b02ad1d968fc Wolfgang Bumiller 2022-01-10 940 seq_puts(s, "\n"); f539da82f21589 Tejun Heo 2019-06-13 941 } 2ee867dcfa2eae Tejun Heo 2015-08-18 942 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org