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 "dso.h" 8 #include "map.h" 9 #include "symbol.h" 10 #include <internal/lib.h> // page_size 11 #include "tests.h" 12 #include "debug.h" 13 #include "machine.h" 14 15 #define UM(x) kallsyms_map->unmap_ip(kallsyms_map, (x)) 16 17 int test__vmlinux_matches_kallsyms(struct test *test __maybe_unused, int subtest __maybe_unused) 18 { 19 int err = -1; 20 struct rb_node *nd; 21 struct symbol *sym; 22 struct map *kallsyms_map, *vmlinux_map, *map; 23 struct machine kallsyms, vmlinux; 24 struct maps *maps = machine__kernel_maps(&vmlinux); 25 u64 mem_start, mem_end; 26 bool header_printed; 27 28 /* 29 * Step 1: 30 * 31 * Init the machines that will hold kernel, modules obtained from 32 * both vmlinux + .ko files and from /proc/kallsyms split by modules. 33 */ 34 machine__init(&kallsyms, "", HOST_KERNEL_ID); 35 machine__init(&vmlinux, "", HOST_KERNEL_ID); 36 37 /* 38 * Step 2: 39 * 40 * Create the kernel maps for kallsyms and the DSO where we will then 41 * load /proc/kallsyms. Also create the modules maps from /proc/modules 42 * and find the .ko files that match them in /lib/modules/`uname -r`/. 43 */ 44 if (machine__create_kernel_maps(&kallsyms) < 0) { 45 pr_debug("machine__create_kernel_maps "); 46 goto out; 47 } 48 49 /* 50 * Step 3: 51 * 52 * Load and split /proc/kallsyms into multiple maps, one per module. 53 * Do not use kcore, as this test was designed before kcore support 54 * and has parts that only make sense if using the non-kcore code. 55 * XXX: extend it to stress the kcorre code as well, hint: the list 56 * of modules extracted from /proc/kcore, in its current form, can't 57 * be compacted against the list of modules found in the "vmlinux" 58 * code and with the one got from /proc/modules from the "kallsyms" code. 59 */ 60 if (machine__load_kallsyms(&kallsyms, "/proc/kallsyms") <= 0) { 61 pr_debug("dso__load_kallsyms "); 62 goto out; 63 } 64 65 /* 66 * Step 4: 67 * 68 * kallsyms will be internally on demand sorted by name so that we can 69 * find the reference relocation * symbol, i.e. the symbol we will use 70 * to see if the running kernel was relocated by checking if it has the 71 * same value in the vmlinux file we load. 72 */ 73 kallsyms_map = machine__kernel_map(&kallsyms); 74 75 /* 76 * Step 5: 77 * 78 * Now repeat step 2, this time for the vmlinux file we'll auto-locate. 79 */ 80 if (machine__create_kernel_maps(&vmlinux) < 0) { 81 pr_debug("machine__create_kernel_maps "); 82 goto out; 83 } 84 85 vmlinux_map = machine__kernel_map(&vmlinux); 86 87 /* 88 * Step 6: 89 * 90 * Locate a vmlinux file in the vmlinux path that has a buildid that 91 * matches the one of the running kernel. 92 * 93 * While doing that look if we find the ref reloc symbol, if we find it 94 * we'll have its ref_reloc_symbol.unrelocated_addr and then 95 * maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines 96 * to fixup the symbols. 97 */ 98 if (machine__load_vmlinux_path(&vmlinux) <= 0) { 99 pr_debug("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n"); 100 err = TEST_SKIP; 101 goto out; 102 } 103 104 err = 0; 105 /* 106 * Step 7: 107 * 108 * Now look at the symbols in the vmlinux DSO and check if we find all of them 109 * in the kallsyms dso. For the ones that are in both, check its names and 110 * end addresses too. 111 */ 112 map__for_each_symbol(vmlinux_map, sym, nd) { 113 struct symbol *pair, *first_pair; 114 115 sym = rb_entry(nd, struct symbol, rb_node); 116 117 if (sym->start == sym->end) 118 continue; 119 120 mem_start = vmlinux_map->unmap_ip(vmlinux_map, sym->start); 121 mem_end = vmlinux_map->unmap_ip(vmlinux_map, sym->end); 122 123 first_pair = machine__find_kernel_symbol(&kallsyms, 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, 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 if (mem_start == kallsyms.vmlinux_map->end) { 167 /* 168 * Ignore aliases to _etext, i.e. to the end of the kernel text area, 169 * such as __indirect_thunk_end. 170 */ 171 continue; 172 } else { 173 pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n", 174 mem_start, sym->name); 175 } 176 177 err = -1; 178 } 179 180 if (verbose <= 0) 181 goto out; 182 183 header_printed = false; 184 185 maps__for_each_entry(maps, map) { 186 struct map * 187 /* 188 * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while 189 * the kernel will have the path for the vmlinux file being used, 190 * so use the short name, less descriptive but the same ("[kernel]" in 191 * both cases. 192 */ 193 pair = maps__find_by_name(&kallsyms.kmaps, (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 maps__for_each_entry(maps, 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 = maps__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 maps__for_each_entry(maps, 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