Hi Marco, I love your patch! Perhaps something to improve: [auto build test WARNING on hnaz-linux-mm/master] [also build test WARNING on arm64/for-next/core linus/master v5.9-rc5] [cannot apply to tip/x86/core next-20200915] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Marco-Elver/KFENCE-A-low-overhea... base: https://github.com/hnaz/linux-mm master config: i386-allyesconfig (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 reproduce (this is a W=1 build): # save the attached .config to linux build tree make W=1 ARCH=i386 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 >>): mm/kfence/kfence_test.c: In function 'report_matches': 150 | } | ^ # https://github.com/0day-ci/linux/commit/e52f64e8d3cbfe2423913871780cf012b... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Marco-Elver/KFENCE-A-low-overhead-sampling-based-memory-safety-error-detector/20200915-212305 git checkout e52f64e8d3cbfe2423913871780cf012b2abeb21 vim +150 mm/kfence/kfence_test.c 74 75 /* Check observed report matches information in @r. */ 76 static bool report_matches(const struct expect_report *r) 77 { 78 bool ret = false; 79 unsigned long flags; 80 typeof(observed.lines) expect; 81 const char *end; 82 char *cur; 83 84 /* Doubled-checked locking. */ 85 if (!report_available()) 86 return false; 87 88 /* Generate expected report contents. */ 89 90 /* Title */ 91 cur = expect[0]; 92 end = &expect[0][sizeof(expect[0]) - 1]; 93 switch (r->type) { 94 case KFENCE_ERROR_OOB: 95 cur += scnprintf(cur, end - cur, "BUG: KFENCE: out-of-bounds"); 96 break; 97 case KFENCE_ERROR_UAF: 98 cur += scnprintf(cur, end - cur, "BUG: KFENCE: use-after-free"); 99 break; 100 case KFENCE_ERROR_CORRUPTION: 101 cur += scnprintf(cur, end - cur, "BUG: KFENCE: memory corruption"); 102 break; 103 case KFENCE_ERROR_INVALID: 104 cur += scnprintf(cur, end - cur, "BUG: KFENCE: invalid access"); 105 break; 106 case KFENCE_ERROR_INVALID_FREE: 107 cur += scnprintf(cur, end - cur, "BUG: KFENCE: invalid free"); 108 break; 109 } 110 111 scnprintf(cur, end - cur, " in %pS", r->fn); 112 /* The exact offset won't match, remove it; also strip module name. */ 113 cur = strchr(expect[0], '+'); 114 if (cur) 115 *cur = '\0'; 116 117 /* Access information */ 118 cur = expect[1]; 119 end = &expect[1][sizeof(expect[1]) - 1]; 120 121 switch (r->type) { 122 case KFENCE_ERROR_OOB: 123 cur += scnprintf(cur, end - cur, "Out-of-bounds access at"); 124 break; 125 case KFENCE_ERROR_UAF: 126 cur += scnprintf(cur, end - cur, "Use-after-free access at"); 127 break; 128 case KFENCE_ERROR_CORRUPTION: 129 cur += scnprintf(cur, end - cur, "Corrupted memory at"); 130 break; 131 case KFENCE_ERROR_INVALID: 132 cur += scnprintf(cur, end - cur, "Invalid access at"); 133 break; 134 case KFENCE_ERROR_INVALID_FREE: 135 cur += scnprintf(cur, end - cur, "Invalid free of"); 136 break; 137 } 138 139 cur += scnprintf(cur, end - cur, " 0x" PTR_FMT, (void *)r->addr); 140 141 spin_lock_irqsave(&observed.lock, flags); 142 if (!report_available()) 143 goto out; /* A new report is being captured. */ 144 145 /* Finally match expected output to what we actually observed. */ 146 ret = strstr(observed.lines[0], expect[0]) && strstr(observed.lines[1], expect[1]); 147 out: 148 spin_unlock_irqrestore(&observed.lock, flags); 149 return ret; 151 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org