#include <linux/compiler.h> #include <linux/rbtree.h> #include <string.h> #include "map.h" #include "symbol.h" #include "util.h" #include "tests.h" #include "debug.h" #include "machine.h" #define UM(x) kallsyms_map->unmap_ip(kallsyms_map, (x)) int test__vmlinux_matches_kallsyms(int subtest __maybe_unused) { int err = -1; struct rb_node *nd; struct symbol *sym; struct map *kallsyms_map, *vmlinux_map, *map; struct machine kallsyms, vmlinux; enum map_type type = MAP__FUNCTION; struct maps *maps = &vmlinux.kmaps.maps[type]; u64 mem_start, mem_end; bool header_printed; /* * Step 1: * * Init the machines that will hold kernel, modules obtained from * both vmlinux + .ko files and from /proc/kallsyms split by modules. */ machine__init(&kallsyms, "", HOST_KERNEL_ID); machine__init(&vmlinux, "", HOST_KERNEL_ID); /* * Step 2: * * Create the kernel maps for kallsyms and the DSO where we will then * load /proc/kallsyms. Also create the modules maps from /proc/modules * and find the .ko files that match them in /lib/modules/`uname -r`/. */ if (machine__create_kernel_maps(&kallsyms) < 0) { pr_debug("machine__create_kernel_maps "); goto out; } /* * Step 3: * * Load and split /proc/kallsyms into multiple maps, one per module. * Do not use kcore, as this test was designed before kcore support * and has parts that only make sense if using the non-kcore code. * XXX: extend it to stress the kcorre code as well, hint: the list * of modules extracted from /proc/kcore, in its current form, can't * be compacted against the list of modules found in the "vmlinux" * code and with the one got from /proc/modules from the "kallsyms" code. */ if (__machine__load_kallsyms(&kallsyms, "/proc/kallsyms", type, true) <= 0) { pr_debug("dso__load_kallsyms "); goto out; } /* * Step 4: * * kallsyms will be internally on demand sorted by name so that we can * find the reference relocation * symbol, i.e. the symbol we will use * to see if the running kernel was relocated by checking if it has the * same value in the vmlinux file we load. */ kallsyms_map = machine__kernel_map(&kallsyms); /* * Step 5: * * Now repeat step 2, this time for the vmlinux file we'll auto-locate. */ if (machine__create_kernel_maps(&vmlinux) < 0) { pr_debug("machine__create_kernel_maps "); goto out; } vmlinux_map = machine__kernel_map(&vmlinux); /* * Step 6: * * Locate a vmlinux file in the vmlinux path that has a buildid that * matches the one of the running kernel. * * While doing that look if we find the ref reloc symbol, if we find it * we'll have its ref_reloc_symbol.unrelocated_addr and then * maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines * to fixup the symbols. */ if (machine__load_vmlinux_path(&vmlinux, type) <= 0) { pr_debug("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n"); err = TEST_SKIP; goto out; } err = 0; /* * Step 7: * * Now look at the symbols in the vmlinux DSO and check if we find all of them * in the kallsyms dso. For the ones that are in both, check its names and * end addresses too. */ for (nd = rb_first(&vmlinux_map->dso->symbols[type]); nd; nd = rb_next(nd)) { struct symbol *pair, *first_pair; sym = rb_entry(nd, struct symbol, rb_node); if (sym->start == sym->end) continue; mem_start = vmlinux_map->unmap_ip(vmlinux_map, sym->start); mem_end = vmlinux_map->unmap_ip(vmlinux_map, sym->end); first_pair = machine__find_kernel_symbol(&kallsyms, type, mem_start, NULL); pair = first_pair; if (pair && UM(pair->start) == mem_start) { next_pair: if (strcmp(sym->name, pair->name) == 0) { /* * kallsyms don't have the symbol end, so we * set that by using the next symbol start - 1, * in some cases we get this up to a page * wrong, trace_kmalloc when I was developing * this code was one such example, 2106 bytes * off the real size. More than that and we * _really_ have a problem. */ s64 skew = mem_end - UM(pair->end); if (llabs(skew) >= page_size) pr_debug("WARN: %#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n", mem_start, sym->name, mem_end, UM(pair->end)); /* * Do not count this as a failure, because we * could really find a case where it's not * possible to get proper function end from * kallsyms. */ continue; } else { pair = machine__find_kernel_symbol_by_name(&kallsyms, type, sym->name, NULL); if (pair) { if (UM(pair->start) == mem_start) goto next_pair; pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n", mem_start, sym->name, pair->name); } else { pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n", mem_start, sym->name, first_pair->name); } continue; } } else pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n", mem_start, sym->name); err = -1; } if (!verbose) goto out; header_printed = false; for (map = maps__first(maps); map; map = map__next(map)) { struct map * /* * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while * the kernel will have the path for the vmlinux file being used, * so use the short name, less descriptive but the same ("[kernel]" in * both cases. */ pair = map_groups__find_by_name(&kallsyms.kmaps, type, (map->dso->kernel ? map->dso->short_name : map->dso->name)); if (pair) { pair->priv = 1; } else { if (!header_printed) { pr_info("WARN: Maps only in vmlinux:\n"); header_printed = true; } map__fprintf(map, stderr); } } header_printed = false; for (map = maps__first(maps); map; map = map__next(map)) { struct map *pair; mem_start = vmlinux_map->unmap_ip(vmlinux_map, map->start); mem_end = vmlinux_map->unmap_ip(vmlinux_map, map->end); pair = map_groups__find(&kallsyms.kmaps, type, mem_start); if (pair == NULL || pair->priv) continue; if (pair->start == mem_start) { if (!header_printed) { pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n"); header_printed = true; } pr_info("WARN: %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as", map->start, map->end, map->pgoff, map->dso->name); if (mem_end != pair->end) pr_info(":\nWARN: *%" PRIx64 "-%" PRIx64 " %" PRIx64, pair->start, pair->end, pair->pgoff); pr_info(" %s\n", pair->dso->name); pair->priv = 1; } } header_printed = false; maps = &kallsyms.kmaps.maps[type]; for (map = maps__first(maps); map; map = map__next(map)) { if (!map->priv) { if (!header_printed) { pr_info("WARN: Maps only in kallsyms:\n"); header_printed = true; } map__fprintf(map, stderr); } } out: machine__exit(&kallsyms); machine__exit(&vmlinux); return err; }