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