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1// DFSAN_OPTIONS=no_huge_pages_for_shadow=false RUN: %clang_dfsan %s -o %t && %run %t2// DFSAN_OPTIONS=no_huge_pages_for_shadow=true RUN: %clang_dfsan %s -o %t && %run %t3// DFSAN_OPTIONS=no_huge_pages_for_shadow=false RUN: %clang_dfsan %s -DORIGIN_TRACKING -mllvm -dfsan-track-origins=1 -o %t && %run %t4// DFSAN_OPTIONS=no_huge_pages_for_shadow=true RUN: %clang_dfsan %s -DORIGIN_TRACKING -mllvm -dfsan-track-origins=1 -o %t && %run %t5 6#include <assert.h>7#include <sanitizer/dfsan_interface.h>8#include <stdbool.h>9#include <stdio.h>10#include <string.h>11#include <sys/mman.h>12#include <unistd.h>13 14size_t get_rss_kb() {15 size_t ret = 0;16 pid_t pid = getpid();17 18 char fname[256];19 sprintf(fname, "/proc/%ld/task/%ld/smaps", (long)pid, (long)pid);20 FILE *f = fopen(fname, "r");21 assert(f);22 23 char buf[256];24 while (fgets(buf, sizeof(buf), f) != NULL) {25 int64_t rss;26 // DFSan's sscanf is broken and doesn't check for ordinary characters in27 // the format string, hence we use strstr as a secondary check28 // (https://github.com/llvm/llvm-project/issues/94769).29 if ((sscanf(buf, "Rss: %ld kB", &rss) == 1) &&30 (strstr(buf, "Rss: ") != NULL))31 ret += rss;32 }33 assert(feof(f));34 fclose(f);35 36 return ret;37}38 39int main(int argc, char **argv) {40 const size_t map_size = 100 << 20;41 size_t before = get_rss_kb();42 43 // mmap and touch all addresses. The overhead is 1x.44 char *p = mmap(NULL, map_size, PROT_READ | PROT_WRITE,45 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);46 memset(p, 0xff, map_size);47 size_t after_mmap = get_rss_kb();48 49 // store labels to all addresses. The overhead is 2x.50 const dfsan_label label = 8;51 char val = 0xff;52 dfsan_set_label(label, &val, sizeof(val));53 memset(p, val, map_size);54 size_t after_mmap_and_set_label = get_rss_kb();55 56 // fixed-mmap the same address. OS recyles pages and reinitializes data at the57 // address. This should be the same to calling munmap.58 p = mmap(p, map_size, PROT_READ | PROT_WRITE,59 MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);60 size_t after_fixed_mmap = get_rss_kb();61 62 // store labels to all addresses.63 memset(p, val, map_size);64 size_t after_mmap_and_set_label2 = get_rss_kb();65 66 // munmap the addresses.67 munmap(p, map_size);68 size_t after_munmap = get_rss_kb();69 70 fprintf(71 stderr,72 "RSS at start: %zu, after mmap: %zu, after mmap+set label: %zu, after "73 "fixed map: %zu, after another mmap+set label: %zu, after munmap: %zu\n",74 before, after_mmap, after_mmap_and_set_label, after_fixed_mmap,75 after_mmap_and_set_label2, after_munmap);76 77 // This is orders of magnitude larger than we expect (typically < 10,000KB).78 // It is a quick check to ensure that the RSS calculation function isn't79 // egregriously wrong.80 assert(before < 1000000);81 82 const size_t mmap_cost_kb = map_size >> 10;83 // Shadow space (1:1 with application memory)84 const size_t mmap_shadow_cost_kb = sizeof(dfsan_label) * mmap_cost_kb;85#ifdef ORIGIN_TRACKING86 // Origin space (1:1 with application memory)87 const size_t mmap_origin_cost_kb = mmap_cost_kb;88#else89 const size_t mmap_origin_cost_kb = 0;90#endif91 assert(after_mmap >= before + mmap_cost_kb);92 assert(after_mmap_and_set_label >=93 after_mmap + mmap_shadow_cost_kb + mmap_origin_cost_kb);94 assert(after_mmap_and_set_label2 >=95 before + mmap_cost_kb + mmap_shadow_cost_kb + mmap_origin_cost_kb);96 97#ifdef ORIGIN_TRACKING98 // This value is chosen based on observed difference.99 const size_t mmap_origin_chain_kb = 4000;100#else101 const size_t mmap_origin_chain_kb = 0;102#endif103 104 // RSS may not change memory amount after munmap to the same level as the105 // start of the program. The assert checks the memory up to a delta.106 const size_t delta = 5000;107 // Origin chains are not freed, even when the origin space which refers to108 // them is freed, so mmap_origin_chain_kb is added to account for this.109 assert(after_fixed_mmap <= before + delta + mmap_origin_chain_kb);110 assert(after_munmap <= before + delta + mmap_origin_chain_kb);111 112 return 0;113}114