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#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"
static int vmlinux_matches_kallsyms_filter(struct map *map __maybe_unused,
struct symbol *sym)
{
bool *visited = symbol__priv(sym);
*visited = true;
return 0;
}
int test__vmlinux_matches_kallsyms(void)
{
int err = -1;
struct rb_node *nd;
struct symbol *sym;
struct map *kallsyms_map, *vmlinux_map;
struct machine kallsyms, vmlinux;
enum map_type type = MAP__FUNCTION;
struct ref_reloc_sym ref_reloc_sym = { .name = "_stext", };
/*
* 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 ");
return -1;
}
/*
* Step 3:
*
* Load and split /proc/kallsyms into multiple maps, one per module.
*/
if (machine__load_kallsyms(&kallsyms, "/proc/kallsyms", type, NULL) <= 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, type);
sym = map__find_symbol_by_name(kallsyms_map, ref_reloc_sym.name, NULL);
if (sym == NULL) {
pr_debug("dso__find_symbol_by_name ");
goto out;
}
ref_reloc_sym.addr = sym->start;
/*
* 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, type);
map__kmap(vmlinux_map)->ref_reloc_sym = &ref_reloc_sym;
/*
* 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,
vmlinux_matches_kallsyms_filter) <= 0) {
pr_debug("machine__load_vmlinux_path ");
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;
bool backwards = true;
sym = rb_entry(nd, struct symbol, rb_node);
if (sym->start == sym->end)
continue;
first_pair = machine__find_kernel_symbol(&kallsyms, type, sym->start, NULL, NULL);
pair = first_pair;
if (pair && pair->start == sym->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 = sym->end - pair->end;
if (llabs(skew) < page_size)
continue;
pr_debug("%#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n",
sym->start, sym->name, sym->end, pair->end);
} else {
struct rb_node *nnd;
detour:
nnd = backwards ? rb_prev(&pair->rb_node) :
rb_next(&pair->rb_node);
if (nnd) {
struct symbol *next = rb_entry(nnd, struct symbol, rb_node);
if (next->start == sym->start) {
pair = next;
goto next_pair;
}
}
if (backwards) {
backwards = false;
pair = first_pair;
goto detour;
}
pr_debug("%#" PRIx64 ": diff name v: %s k: %s\n",
sym->start, sym->name, pair->name);
}
} else
pr_debug("%#" PRIx64 ": %s not on kallsyms\n", sym->start, sym->name);
err = -1;
}
if (!verbose)
goto out;
pr_info("Maps only in vmlinux:\n");
for (nd = rb_first(&vmlinux.kmaps.maps[type]); nd; nd = rb_next(nd)) {
struct map *pos = rb_entry(nd, struct map, rb_node), *pair;
/*
* 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,
(pos->dso->kernel ?
pos->dso->short_name :
pos->dso->name));
if (pair)
pair->priv = 1;
else
map__fprintf(pos, stderr);
}
pr_info("Maps in vmlinux with a different name in kallsyms:\n");
for (nd = rb_first(&vmlinux.kmaps.maps[type]); nd; nd = rb_next(nd)) {
struct map *pos = rb_entry(nd, struct map, rb_node), *pair;
pair = map_groups__find(&kallsyms.kmaps, type, pos->start);
if (pair == NULL || pair->priv)
continue;
if (pair->start == pos->start) {
pair->priv = 1;
pr_info(" %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as",
pos->start, pos->end, pos->pgoff, pos->dso->name);
if (pos->pgoff != pair->pgoff || pos->end != pair->end)
pr_info(": \n*%" PRIx64 "-%" PRIx64 " %" PRIx64 "",
pair->start, pair->end, pair->pgoff);
pr_info(" %s\n", pair->dso->name);
pair->priv = 1;
}
}
pr_info("Maps only in kallsyms:\n");
for (nd = rb_first(&kallsyms.kmaps.maps[type]);
nd; nd = rb_next(nd)) {
struct map *pos = rb_entry(nd, struct map, rb_node);
if (!pos->priv)
map__fprintf(pos, stderr);
}
out:
return err;
}
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