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 struct maps *maps = machine__kernel_maps(&vmlinux); 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") <= 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) <= 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 map__for_each_symbol(vmlinux_map, sym, 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, mem_start, NULL); 122 pair = first_pair; 123 124 if (pair && UM(pair->start) == mem_start) { 125 next_pair: 126 if (arch__compare_symbol_names(sym->name, pair->name) == 0) { 127 /* 128 * kallsyms don't have the symbol end, so we 129 * set that by using the next symbol start - 1, 130 * in some cases we get this up to a page 131 * wrong, trace_kmalloc when I was developing 132 * this code was one such example, 2106 bytes 133 * off the real size. More than that and we 134 * _really_ have a problem. 135 */ 136 s64 skew = mem_end - UM(pair->end); 137 if (llabs(skew) >= page_size) 138 pr_debug("WARN: %#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n", 139 mem_start, sym->name, mem_end, 140 UM(pair->end)); 141 142 /* 143 * Do not count this as a failure, because we 144 * could really find a case where it's not 145 * possible to get proper function end from 146 * kallsyms. 147 */ 148 continue; 149 } else { 150 pair = machine__find_kernel_symbol_by_name(&kallsyms, sym->name, NULL); 151 if (pair) { 152 if (UM(pair->start) == mem_start) 153 goto next_pair; 154 155 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n", 156 mem_start, sym->name, pair->name); 157 } else { 158 pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n", 159 mem_start, sym->name, first_pair->name); 160 } 161 162 continue; 163 } 164 } else 165 pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n", 166 mem_start, sym->name); 167 168 err = -1; 169 } 170 171 if (verbose <= 0) 172 goto out; 173 174 header_printed = false; 175 176 for (map = maps__first(maps); map; map = map__next(map)) { 177 struct map * 178 /* 179 * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while 180 * the kernel will have the path for the vmlinux file being used, 181 * so use the short name, less descriptive but the same ("[kernel]" in 182 * both cases. 183 */ 184 pair = map_groups__find_by_name(&kallsyms.kmaps, 185 (map->dso->kernel ? 186 map->dso->short_name : 187 map->dso->name)); 188 if (pair) { 189 pair->priv = 1; 190 } else { 191 if (!header_printed) { 192 pr_info("WARN: Maps only in vmlinux:\n"); 193 header_printed = true; 194 } 195 map__fprintf(map, stderr); 196 } 197 } 198 199 header_printed = false; 200 201 for (map = maps__first(maps); map; map = map__next(map)) { 202 struct map *pair; 203 204 mem_start = vmlinux_map->unmap_ip(vmlinux_map, map->start); 205 mem_end = vmlinux_map->unmap_ip(vmlinux_map, map->end); 206 207 pair = map_groups__find(&kallsyms.kmaps, mem_start); 208 if (pair == NULL || pair->priv) 209 continue; 210 211 if (pair->start == mem_start) { 212 if (!header_printed) { 213 pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n"); 214 header_printed = true; 215 } 216 217 pr_info("WARN: %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as", 218 map->start, map->end, map->pgoff, map->dso->name); 219 if (mem_end != pair->end) 220 pr_info(":\nWARN: *%" PRIx64 "-%" PRIx64 " %" PRIx64, 221 pair->start, pair->end, pair->pgoff); 222 pr_info(" %s\n", pair->dso->name); 223 pair->priv = 1; 224 } 225 } 226 227 header_printed = false; 228 229 maps = machine__kernel_maps(&kallsyms); 230 231 for (map = maps__first(maps); map; map = map__next(map)) { 232 if (!map->priv) { 233 if (!header_printed) { 234 pr_info("WARN: Maps only in kallsyms:\n"); 235 header_printed = true; 236 } 237 map__fprintf(map, stderr); 238 } 239 } 240 out: 241 machine__exit(&kallsyms); 242 machine__exit(&vmlinux); 243 return err; 244 } 245