1 #include <linux/compiler.h> 2 #include <linux/rbtree.h> 3 #include <inttypes.h> 4 #include <string.h> 5 #include "map.h" 6 #include "symbol.h" 7 #include "util.h" 8 #include "tests.h" 9 #include "debug.h" 10 #include "machine.h" 11 12 #define UM(x) kallsyms_map->unmap_ip(kallsyms_map, (x)) 13 14 int test__vmlinux_matches_kallsyms(struct test *test __maybe_unused, int subtest __maybe_unused) 15 { 16 int err = -1; 17 struct rb_node *nd; 18 struct symbol *sym; 19 struct map *kallsyms_map, *vmlinux_map, *map; 20 struct machine kallsyms, vmlinux; 21 enum map_type type = MAP__FUNCTION; 22 struct maps *maps = &vmlinux.kmaps.maps[type]; 23 u64 mem_start, mem_end; 24 bool header_printed; 25 26 /* 27 * Step 1: 28 * 29 * Init the machines that will hold kernel, modules obtained from 30 * both vmlinux + .ko files and from /proc/kallsyms split by modules. 31 */ 32 machine__init(&kallsyms, "", HOST_KERNEL_ID); 33 machine__init(&vmlinux, "", HOST_KERNEL_ID); 34 35 /* 36 * Step 2: 37 * 38 * Create the kernel maps for kallsyms and the DSO where we will then 39 * load /proc/kallsyms. Also create the modules maps from /proc/modules 40 * and find the .ko files that match them in /lib/modules/`uname -r`/. 41 */ 42 if (machine__create_kernel_maps(&kallsyms) < 0) { 43 pr_debug("machine__create_kernel_maps "); 44 goto out; 45 } 46 47 /* 48 * Step 3: 49 * 50 * Load and split /proc/kallsyms into multiple maps, one per module. 51 * Do not use kcore, as this test was designed before kcore support 52 * and has parts that only make sense if using the non-kcore code. 53 * XXX: extend it to stress the kcorre code as well, hint: the list 54 * of modules extracted from /proc/kcore, in its current form, can't 55 * be compacted against the list of modules found in the "vmlinux" 56 * code and with the one got from /proc/modules from the "kallsyms" code. 57 */ 58 if (__machine__load_kallsyms(&kallsyms, "/proc/kallsyms", type, true) <= 0) { 59 pr_debug("dso__load_kallsyms "); 60 goto out; 61 } 62 63 /* 64 * Step 4: 65 * 66 * kallsyms will be internally on demand sorted by name so that we can 67 * find the reference relocation * symbol, i.e. the symbol we will use 68 * to see if the running kernel was relocated by checking if it has the 69 * same value in the vmlinux file we load. 70 */ 71 kallsyms_map = machine__kernel_map(&kallsyms); 72 73 /* 74 * Step 5: 75 * 76 * Now repeat step 2, this time for the vmlinux file we'll auto-locate. 77 */ 78 if (machine__create_kernel_maps(&vmlinux) < 0) { 79 pr_debug("machine__create_kernel_maps "); 80 goto out; 81 } 82 83 vmlinux_map = machine__kernel_map(&vmlinux); 84 85 /* 86 * Step 6: 87 * 88 * Locate a vmlinux file in the vmlinux path that has a buildid that 89 * matches the one of the running kernel. 90 * 91 * While doing that look if we find the ref reloc symbol, if we find it 92 * we'll have its ref_reloc_symbol.unrelocated_addr and then 93 * maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines 94 * to fixup the symbols. 95 */ 96 if (machine__load_vmlinux_path(&vmlinux, type) <= 0) { 97 pr_debug("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n"); 98 err = TEST_SKIP; 99 goto out; 100 } 101 102 err = 0; 103 /* 104 * Step 7: 105 * 106 * Now look at the symbols in the vmlinux DSO and check if we find all of them 107 * in the kallsyms dso. For the ones that are in both, check its names and 108 * end addresses too. 109 */ 110 for (nd = rb_first(&vmlinux_map->dso->symbols[type]); nd; nd = rb_next(nd)) { 111 struct symbol *pair, *first_pair; 112 113 sym = rb_entry(nd, struct symbol, rb_node); 114 115 if (sym->start == sym->end) 116 continue; 117 118 mem_start = vmlinux_map->unmap_ip(vmlinux_map, sym->start); 119 mem_end = vmlinux_map->unmap_ip(vmlinux_map, sym->end); 120 121 first_pair = machine__find_kernel_symbol(&kallsyms, type, 122 mem_start, NULL); 123 pair = first_pair; 124 125 if (pair && UM(pair->start) == mem_start) { 126 next_pair: 127 if (strcmp(sym->name, pair->name) == 0) { 128 /* 129 * kallsyms don't have the symbol end, so we 130 * set that by using the next symbol start - 1, 131 * in some cases we get this up to a page 132 * wrong, trace_kmalloc when I was developing 133 * this code was one such example, 2106 bytes 134 * off the real size. More than that and we 135 * _really_ have a problem. 136 */ 137 s64 skew = mem_end - UM(pair->end); 138 if (llabs(skew) >= page_size) 139 pr_debug("WARN: %#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n", 140 mem_start, sym->name, mem_end, 141 UM(pair->end)); 142 143 /* 144 * Do not count this as a failure, because we 145 * could really find a case where it's not 146 * possible to get proper function end from 147 * kallsyms. 148 */ 149 continue; 150 } else { 151 pair = machine__find_kernel_symbol_by_name(&kallsyms, type, sym->name, NULL); 152 if (pair) { 153 if (UM(pair->start) == mem_start) 154 goto next_pair; 155 156 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n", 157 mem_start, sym->name, pair->name); 158 } else { 159 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n", 160 mem_start, sym->name, first_pair->name); 161 } 162 163 continue; 164 } 165 } else 166 pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n", 167 mem_start, sym->name); 168 169 err = -1; 170 } 171 172 if (verbose <= 0) 173 goto out; 174 175 header_printed = false; 176 177 for (map = maps__first(maps); map; map = map__next(map)) { 178 struct map * 179 /* 180 * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while 181 * the kernel will have the path for the vmlinux file being used, 182 * so use the short name, less descriptive but the same ("[kernel]" in 183 * both cases. 184 */ 185 pair = map_groups__find_by_name(&kallsyms.kmaps, type, 186 (map->dso->kernel ? 187 map->dso->short_name : 188 map->dso->name)); 189 if (pair) { 190 pair->priv = 1; 191 } else { 192 if (!header_printed) { 193 pr_info("WARN: Maps only in vmlinux:\n"); 194 header_printed = true; 195 } 196 map__fprintf(map, stderr); 197 } 198 } 199 200 header_printed = false; 201 202 for (map = maps__first(maps); map; map = map__next(map)) { 203 struct map *pair; 204 205 mem_start = vmlinux_map->unmap_ip(vmlinux_map, map->start); 206 mem_end = vmlinux_map->unmap_ip(vmlinux_map, map->end); 207 208 pair = map_groups__find(&kallsyms.kmaps, type, mem_start); 209 if (pair == NULL || pair->priv) 210 continue; 211 212 if (pair->start == mem_start) { 213 if (!header_printed) { 214 pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n"); 215 header_printed = true; 216 } 217 218 pr_info("WARN: %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as", 219 map->start, map->end, map->pgoff, map->dso->name); 220 if (mem_end != pair->end) 221 pr_info(":\nWARN: *%" PRIx64 "-%" PRIx64 " %" PRIx64, 222 pair->start, pair->end, pair->pgoff); 223 pr_info(" %s\n", pair->dso->name); 224 pair->priv = 1; 225 } 226 } 227 228 header_printed = false; 229 230 maps = &kallsyms.kmaps.maps[type]; 231 232 for (map = maps__first(maps); map; map = map__next(map)) { 233 if (!map->priv) { 234 if (!header_printed) { 235 pr_info("WARN: Maps only in kallsyms:\n"); 236 header_printed = true; 237 } 238 map__fprintf(map, stderr); 239 } 240 } 241 out: 242 machine__exit(&kallsyms); 243 machine__exit(&vmlinux); 244 return err; 245 } 246