253 lines
6.7 KiB
C
253 lines
6.7 KiB
C
#include <linux/compiler.h>
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#include <linux/rbtree.h>
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#include <string.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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static int vmlinux_matches_kallsyms_filter(struct map *map __maybe_unused,
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struct symbol *sym)
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{
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bool *visited = symbol__priv(sym);
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*visited = true;
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return 0;
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}
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#define UM(x) kallsyms_map->unmap_ip(kallsyms_map, (x))
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int test__vmlinux_matches_kallsyms(void)
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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;
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struct machine kallsyms, vmlinux;
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enum map_type type = MAP__FUNCTION;
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struct ref_reloc_sym ref_reloc_sym = { .name = "_stext", };
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u64 mem_start, mem_end;
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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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*/
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if (machine__load_kallsyms(&kallsyms, "/proc/kallsyms", type, NULL) <= 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, type);
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sym = map__find_symbol_by_name(kallsyms_map, ref_reloc_sym.name, NULL);
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if (sym == NULL) {
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pr_debug("dso__find_symbol_by_name ");
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goto out;
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}
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ref_reloc_sym.addr = UM(sym->start);
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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, type);
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map__kmap(vmlinux_map)->ref_reloc_sym = &ref_reloc_sym;
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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, type,
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vmlinux_matches_kallsyms_filter) <= 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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for (nd = rb_first(&vmlinux_map->dso->symbols[type]); nd; nd = rb_next(nd)) {
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struct symbol *pair, *first_pair;
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bool backwards = true;
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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, type,
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mem_start, NULL, 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 (strcmp(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("%#" 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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struct rb_node *nnd;
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detour:
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nnd = backwards ? rb_prev(&pair->rb_node) :
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rb_next(&pair->rb_node);
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if (nnd) {
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struct symbol *next = rb_entry(nnd, struct symbol, rb_node);
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if (UM(next->start) == mem_start) {
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pair = next;
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goto next_pair;
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}
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}
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if (backwards) {
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backwards = false;
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pair = first_pair;
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goto detour;
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}
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pr_debug("%#" PRIx64 ": diff name v: %s k: %s\n",
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mem_start, sym->name, pair->name);
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}
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} else
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pr_debug("%#" PRIx64 ": %s not on kallsyms\n",
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mem_start, sym->name);
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err = -1;
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}
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if (!verbose)
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goto out;
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pr_info("Maps only in vmlinux:\n");
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for (nd = rb_first(&vmlinux.kmaps.maps[type]); nd; nd = rb_next(nd)) {
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struct map *pos = rb_entry(nd, struct map, rb_node), *pair;
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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, type,
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(pos->dso->kernel ?
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pos->dso->short_name :
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pos->dso->name));
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if (pair)
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pair->priv = 1;
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else
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map__fprintf(pos, stderr);
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}
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pr_info("Maps in vmlinux with a different name in kallsyms:\n");
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for (nd = rb_first(&vmlinux.kmaps.maps[type]); nd; nd = rb_next(nd)) {
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struct map *pos = rb_entry(nd, struct map, rb_node), *pair;
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mem_start = vmlinux_map->unmap_ip(vmlinux_map, pos->start);
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mem_end = vmlinux_map->unmap_ip(vmlinux_map, pos->end);
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pair = map_groups__find(&kallsyms.kmaps, type, 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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pair->priv = 1;
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pr_info(" %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as",
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pos->start, pos->end, pos->pgoff, pos->dso->name);
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if (mem_end != pair->end)
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pr_info(":\n*%" 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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pr_info("Maps only in kallsyms:\n");
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for (nd = rb_first(&kallsyms.kmaps.maps[type]);
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nd; nd = rb_next(nd)) {
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struct map *pos = rb_entry(nd, struct map, rb_node);
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if (!pos->priv)
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map__fprintf(pos, stderr);
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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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