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 <stdlib.h> 7 #include "map.h" 8 #include "symbol.h" 9 #include "util.h" 10 #include "tests.h" 11 #include "debug.h" 12 #include "machine.h" 13 14 #define UM(x) kallsyms_map->unmap_ip(kallsyms_map, (x)) 15 16 int test__vmlinux_matches_kallsyms(struct test *test __maybe_unused, int subtest __maybe_unused) 17 { 18 int err = -1; 19 struct rb_node *nd; 20 struct symbol *sym; 21 struct map *kallsyms_map, *vmlinux_map, *map; 22 struct machine kallsyms, vmlinux; 23 struct maps *maps = machine__kernel_maps(&vmlinux); 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") <= 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) <= 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 map__for_each_symbol(vmlinux_map, sym, 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, mem_start, NULL); 123 pair = first_pair; 124 125 if (pair && UM(pair->start) == mem_start) { 126 next_pair: 127 if (arch__compare_symbol_names(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, 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 if (mem_start == kallsyms.vmlinux_map->end) { 166 /* 167 * Ignore aliases to _etext, i.e. to the end of the kernel text area, 168 * such as __indirect_thunk_end. 169 */ 170 continue; 171 } else { 172 pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n", 173 mem_start, sym->name); 174 } 175 176 err = -1; 177 } 178 179 if (verbose <= 0) 180 goto out; 181 182 header_printed = false; 183 184 for (map = maps__first(maps); map; map = map__next(map)) { 185 struct map * 186 /* 187 * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while 188 * the kernel will have the path for the vmlinux file being used, 189 * so use the short name, less descriptive but the same ("[kernel]" in 190 * both cases. 191 */ 192 pair = map_groups__find_by_name(&kallsyms.kmaps, 193 (map->dso->kernel ? 194 map->dso->short_name : 195 map->dso->name)); 196 if (pair) { 197 pair->priv = 1; 198 } else { 199 if (!header_printed) { 200 pr_info("WARN: Maps only in vmlinux:\n"); 201 header_printed = true; 202 } 203 map__fprintf(map, stderr); 204 } 205 } 206 207 header_printed = false; 208 209 for (map = maps__first(maps); map; map = map__next(map)) { 210 struct map *pair; 211 212 mem_start = vmlinux_map->unmap_ip(vmlinux_map, map->start); 213 mem_end = vmlinux_map->unmap_ip(vmlinux_map, map->end); 214 215 pair = map_groups__find(&kallsyms.kmaps, mem_start); 216 if (pair == NULL || pair->priv) 217 continue; 218 219 if (pair->start == mem_start) { 220 if (!header_printed) { 221 pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n"); 222 header_printed = true; 223 } 224 225 pr_info("WARN: %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as", 226 map->start, map->end, map->pgoff, map->dso->name); 227 if (mem_end != pair->end) 228 pr_info(":\nWARN: *%" PRIx64 "-%" PRIx64 " %" PRIx64, 229 pair->start, pair->end, pair->pgoff); 230 pr_info(" %s\n", pair->dso->name); 231 pair->priv = 1; 232 } 233 } 234 235 header_printed = false; 236 237 maps = machine__kernel_maps(&kallsyms); 238 239 for (map = maps__first(maps); map; map = map__next(map)) { 240 if (!map->priv) { 241 if (!header_printed) { 242 pr_info("WARN: Maps only in kallsyms:\n"); 243 header_printed = true; 244 } 245 map__fprintf(map, stderr); 246 } 247 } 248 out: 249 machine__exit(&kallsyms); 250 machine__exit(&vmlinux); 251 return err; 252 } 253