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