1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/compiler.h> 3 #include <linux/rbtree.h> 4 #include <inttypes.h> 5 #include <string.h> 6 #include "map.h" 7 #include "symbol.h" 8 #include "util.h" 9 #include "tests.h" 10 #include "debug.h" 11 #include "machine.h" 12 13 #define UM(x) kallsyms_map->unmap_ip(kallsyms_map, (x)) 14 15 int test__vmlinux_matches_kallsyms(struct test *test __maybe_unused, int subtest __maybe_unused) 16 { 17 int err = -1; 18 struct rb_node *nd; 19 struct symbol *sym; 20 struct map *kallsyms_map, *vmlinux_map, *map; 21 struct machine kallsyms, vmlinux; 22 enum map_type type = MAP__FUNCTION; 23 struct maps *maps = &vmlinux.kmaps.maps[type]; 24 u64 mem_start, mem_end; 25 bool header_printed; 26 27 /* 28 * Step 1: 29 * 30 * Init the machines that will hold kernel, modules obtained from 31 * both vmlinux + .ko files and from /proc/kallsyms split by modules. 32 */ 33 machine__init(&kallsyms, "", HOST_KERNEL_ID); 34 machine__init(&vmlinux, "", HOST_KERNEL_ID); 35 36 /* 37 * Step 2: 38 * 39 * Create the kernel maps for kallsyms and the DSO where we will then 40 * load /proc/kallsyms. Also create the modules maps from /proc/modules 41 * and find the .ko files that match them in /lib/modules/`uname -r`/. 42 */ 43 if (machine__create_kernel_maps(&kallsyms) < 0) { 44 pr_debug("machine__create_kernel_maps "); 45 goto out; 46 } 47 48 /* 49 * Step 3: 50 * 51 * Load and split /proc/kallsyms into multiple maps, one per module. 52 * Do not use kcore, as this test was designed before kcore support 53 * and has parts that only make sense if using the non-kcore code. 54 * XXX: extend it to stress the kcorre code as well, hint: the list 55 * of modules extracted from /proc/kcore, in its current form, can't 56 * be compacted against the list of modules found in the "vmlinux" 57 * code and with the one got from /proc/modules from the "kallsyms" code. 58 */ 59 if (machine__load_kallsyms(&kallsyms, "/proc/kallsyms", type) <= 0) { 60 pr_debug("dso__load_kallsyms "); 61 goto out; 62 } 63 64 /* 65 * Step 4: 66 * 67 * kallsyms will be internally on demand sorted by name so that we can 68 * find the reference relocation * symbol, i.e. the symbol we will use 69 * to see if the running kernel was relocated by checking if it has the 70 * same value in the vmlinux file we load. 71 */ 72 kallsyms_map = machine__kernel_map(&kallsyms); 73 74 /* 75 * Step 5: 76 * 77 * Now repeat step 2, this time for the vmlinux file we'll auto-locate. 78 */ 79 if (machine__create_kernel_maps(&vmlinux) < 0) { 80 pr_debug("machine__create_kernel_maps "); 81 goto out; 82 } 83 84 vmlinux_map = machine__kernel_map(&vmlinux); 85 86 /* 87 * Step 6: 88 * 89 * Locate a vmlinux file in the vmlinux path that has a buildid that 90 * matches the one of the running kernel. 91 * 92 * While doing that look if we find the ref reloc symbol, if we find it 93 * we'll have its ref_reloc_symbol.unrelocated_addr and then 94 * maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines 95 * to fixup the symbols. 96 */ 97 if (machine__load_vmlinux_path(&vmlinux, type) <= 0) { 98 pr_debug("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n"); 99 err = TEST_SKIP; 100 goto out; 101 } 102 103 err = 0; 104 /* 105 * Step 7: 106 * 107 * Now look at the symbols in the vmlinux DSO and check if we find all of them 108 * in the kallsyms dso. For the ones that are in both, check its names and 109 * end addresses too. 110 */ 111 for (nd = rb_first(&vmlinux_map->dso->symbols[type]); nd; nd = rb_next(nd)) { 112 struct symbol *pair, *first_pair; 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); 124 pair = first_pair; 125 126 if (pair && UM(pair->start) == mem_start) { 127 next_pair: 128 if (arch__compare_symbol_names(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("WARN: %#" 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 } else { 152 pair = machine__find_kernel_symbol_by_name(&kallsyms, type, sym->name, NULL); 153 if (pair) { 154 if (UM(pair->start) == mem_start) 155 goto next_pair; 156 157 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n", 158 mem_start, sym->name, pair->name); 159 } else { 160 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n", 161 mem_start, sym->name, first_pair->name); 162 } 163 164 continue; 165 } 166 } else 167 pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n", 168 mem_start, sym->name); 169 170 err = -1; 171 } 172 173 if (verbose <= 0) 174 goto out; 175 176 header_printed = false; 177 178 for (map = maps__first(maps); map; map = map__next(map)) { 179 struct map * 180 /* 181 * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while 182 * the kernel will have the path for the vmlinux file being used, 183 * so use the short name, less descriptive but the same ("[kernel]" in 184 * both cases. 185 */ 186 pair = map_groups__find_by_name(&kallsyms.kmaps, type, 187 (map->dso->kernel ? 188 map->dso->short_name : 189 map->dso->name)); 190 if (pair) { 191 pair->priv = 1; 192 } else { 193 if (!header_printed) { 194 pr_info("WARN: Maps only in vmlinux:\n"); 195 header_printed = true; 196 } 197 map__fprintf(map, stderr); 198 } 199 } 200 201 header_printed = false; 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 if (!header_printed) { 215 pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n"); 216 header_printed = true; 217 } 218 219 pr_info("WARN: %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as", 220 map->start, map->end, map->pgoff, map->dso->name); 221 if (mem_end != pair->end) 222 pr_info(":\nWARN: *%" 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 header_printed = false; 230 231 maps = &kallsyms.kmaps.maps[type]; 232 233 for (map = maps__first(maps); map; map = map__next(map)) { 234 if (!map->priv) { 235 if (!header_printed) { 236 pr_info("WARN: Maps only in kallsyms:\n"); 237 header_printed = true; 238 } 239 map__fprintf(map, stderr); 240 } 241 } 242 out: 243 machine__exit(&kallsyms); 244 machine__exit(&vmlinux); 245 return err; 246 } 247