253 lines
7.0 KiB
C
253 lines
7.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/compiler.h>
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#include <linux/rbtree.h>
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#include <inttypes.h>
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#include <string.h>
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#include <stdlib.h>
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#include "map.h"
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#include "symbol.h"
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#include "util.h"
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#include "tests.h"
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#include "debug.h"
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#include "machine.h"
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#define UM(x) kallsyms_map->unmap_ip(kallsyms_map, (x))
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int test__vmlinux_matches_kallsyms(struct test *test __maybe_unused, int subtest __maybe_unused)
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{
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int err = -1;
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struct rb_node *nd;
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struct symbol *sym;
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struct map *kallsyms_map, *vmlinux_map, *map;
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struct machine kallsyms, vmlinux;
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struct maps *maps = machine__kernel_maps(&vmlinux);
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u64 mem_start, mem_end;
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bool header_printed;
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/*
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* Step 1:
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*
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* Init the machines that will hold kernel, modules obtained from
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* both vmlinux + .ko files and from /proc/kallsyms split by modules.
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*/
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machine__init(&kallsyms, "", HOST_KERNEL_ID);
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machine__init(&vmlinux, "", HOST_KERNEL_ID);
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/*
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* Step 2:
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*
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* Create the kernel maps for kallsyms and the DSO where we will then
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* load /proc/kallsyms. Also create the modules maps from /proc/modules
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* and find the .ko files that match them in /lib/modules/`uname -r`/.
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*/
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if (machine__create_kernel_maps(&kallsyms) < 0) {
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pr_debug("machine__create_kernel_maps ");
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goto out;
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}
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/*
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* Step 3:
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*
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* Load and split /proc/kallsyms into multiple maps, one per module.
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* Do not use kcore, as this test was designed before kcore support
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* and has parts that only make sense if using the non-kcore code.
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* XXX: extend it to stress the kcorre code as well, hint: the list
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* of modules extracted from /proc/kcore, in its current form, can't
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* be compacted against the list of modules found in the "vmlinux"
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* code and with the one got from /proc/modules from the "kallsyms" code.
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*/
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if (machine__load_kallsyms(&kallsyms, "/proc/kallsyms") <= 0) {
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pr_debug("dso__load_kallsyms ");
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goto out;
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}
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/*
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* Step 4:
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*
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* kallsyms will be internally on demand sorted by name so that we can
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* find the reference relocation * symbol, i.e. the symbol we will use
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* to see if the running kernel was relocated by checking if it has the
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* same value in the vmlinux file we load.
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*/
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kallsyms_map = machine__kernel_map(&kallsyms);
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/*
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* Step 5:
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*
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* Now repeat step 2, this time for the vmlinux file we'll auto-locate.
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*/
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if (machine__create_kernel_maps(&vmlinux) < 0) {
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pr_debug("machine__create_kernel_maps ");
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goto out;
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}
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vmlinux_map = machine__kernel_map(&vmlinux);
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/*
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* Step 6:
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*
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* Locate a vmlinux file in the vmlinux path that has a buildid that
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* matches the one of the running kernel.
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*
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* While doing that look if we find the ref reloc symbol, if we find it
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* we'll have its ref_reloc_symbol.unrelocated_addr and then
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* maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines
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* to fixup the symbols.
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*/
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if (machine__load_vmlinux_path(&vmlinux) <= 0) {
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pr_debug("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n");
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err = TEST_SKIP;
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goto out;
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}
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err = 0;
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/*
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* Step 7:
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*
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* Now look at the symbols in the vmlinux DSO and check if we find all of them
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* in the kallsyms dso. For the ones that are in both, check its names and
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* end addresses too.
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*/
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map__for_each_symbol(vmlinux_map, sym, nd) {
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struct symbol *pair, *first_pair;
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sym = rb_entry(nd, struct symbol, rb_node);
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if (sym->start == sym->end)
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continue;
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mem_start = vmlinux_map->unmap_ip(vmlinux_map, sym->start);
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mem_end = vmlinux_map->unmap_ip(vmlinux_map, sym->end);
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first_pair = machine__find_kernel_symbol(&kallsyms, mem_start, NULL);
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pair = first_pair;
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if (pair && UM(pair->start) == mem_start) {
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next_pair:
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if (arch__compare_symbol_names(sym->name, pair->name) == 0) {
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/*
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* kallsyms don't have the symbol end, so we
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* set that by using the next symbol start - 1,
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* in some cases we get this up to a page
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* wrong, trace_kmalloc when I was developing
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* this code was one such example, 2106 bytes
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* off the real size. More than that and we
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* _really_ have a problem.
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*/
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s64 skew = mem_end - UM(pair->end);
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if (llabs(skew) >= page_size)
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pr_debug("WARN: %#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n",
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mem_start, sym->name, mem_end,
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UM(pair->end));
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/*
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* Do not count this as a failure, because we
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* could really find a case where it's not
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* possible to get proper function end from
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* kallsyms.
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*/
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continue;
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} else {
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pair = machine__find_kernel_symbol_by_name(&kallsyms, sym->name, NULL);
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if (pair) {
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if (UM(pair->start) == mem_start)
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goto next_pair;
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pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
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mem_start, sym->name, pair->name);
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} else {
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pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
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mem_start, sym->name, first_pair->name);
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}
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continue;
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}
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} else if (mem_start == kallsyms.vmlinux_map->end) {
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/*
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* Ignore aliases to _etext, i.e. to the end of the kernel text area,
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* such as __indirect_thunk_end.
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*/
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continue;
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} else {
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pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n",
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mem_start, sym->name);
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}
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err = -1;
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}
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if (verbose <= 0)
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goto out;
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header_printed = false;
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for (map = maps__first(maps); map; map = map__next(map)) {
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struct map *
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/*
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* If it is the kernel, kallsyms is always "[kernel.kallsyms]", while
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* the kernel will have the path for the vmlinux file being used,
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* so use the short name, less descriptive but the same ("[kernel]" in
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* both cases.
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*/
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pair = map_groups__find_by_name(&kallsyms.kmaps,
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(map->dso->kernel ?
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map->dso->short_name :
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map->dso->name));
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if (pair) {
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pair->priv = 1;
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} else {
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if (!header_printed) {
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pr_info("WARN: Maps only in vmlinux:\n");
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header_printed = true;
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}
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map__fprintf(map, stderr);
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}
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}
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header_printed = false;
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for (map = maps__first(maps); map; map = map__next(map)) {
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struct map *pair;
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mem_start = vmlinux_map->unmap_ip(vmlinux_map, map->start);
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mem_end = vmlinux_map->unmap_ip(vmlinux_map, map->end);
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pair = map_groups__find(&kallsyms.kmaps, mem_start);
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if (pair == NULL || pair->priv)
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continue;
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if (pair->start == mem_start) {
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if (!header_printed) {
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pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n");
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header_printed = true;
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}
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pr_info("WARN: %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as",
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map->start, map->end, map->pgoff, map->dso->name);
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if (mem_end != pair->end)
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pr_info(":\nWARN: *%" PRIx64 "-%" PRIx64 " %" PRIx64,
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pair->start, pair->end, pair->pgoff);
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pr_info(" %s\n", pair->dso->name);
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pair->priv = 1;
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}
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}
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header_printed = false;
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maps = machine__kernel_maps(&kallsyms);
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for (map = maps__first(maps); map; map = map__next(map)) {
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if (!map->priv) {
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if (!header_printed) {
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pr_info("WARN: Maps only in kallsyms:\n");
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header_printed = true;
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}
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map__fprintf(map, stderr);
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}
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}
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out:
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machine__exit(&kallsyms);
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machine__exit(&vmlinux);
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return err;
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}
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