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85 lines
2.7 KiB
85 lines
2.7 KiB
// DFSAN_OPTIONS=no_huge_pages_for_shadow=false RUN: %clang_dfsan %s -o %t && setarch `uname -m` -R %run %t
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// DFSAN_OPTIONS=no_huge_pages_for_shadow=true RUN: %clang_dfsan %s -o %t && setarch `uname -m` -R %run %t
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#include <assert.h>
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#include <sanitizer/dfsan_interface.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <unistd.h>
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size_t get_rss_kb() {
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size_t ret = 0;
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pid_t pid = getpid();
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char fname[256];
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sprintf(fname, "/proc/%ld/task/%ld/smaps", (long)pid, (long)pid);
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FILE *f = fopen(fname, "r");
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assert(f);
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char buf[256];
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while (fgets(buf, sizeof(buf), f) != NULL) {
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int64_t rss;
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if (sscanf(buf, "Rss: %ld kB", &rss) == 1)
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ret += rss;
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}
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assert(feof(f));
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fclose(f);
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return ret;
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}
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int main(int argc, char **argv) {
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const size_t map_size = 100 << 20;
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size_t before = get_rss_kb();
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// mmap and touch all addresses. The overhead is 1x.
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char *p = mmap(NULL, map_size, PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
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memset(p, 0xff, map_size);
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size_t after_mmap = get_rss_kb();
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// store labels to all addresses. The overhead is 2x.
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const dfsan_label label = dfsan_create_label("l", 0);
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char val = 0xff;
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dfsan_set_label(label, &val, sizeof(val));
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memset(p, val, map_size);
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size_t after_mmap_and_set_label = get_rss_kb();
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// fixed-mmap the same address. OS recyles pages and reinitializes data at the
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// address. This should be the same to calling munmap.
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p = mmap(p, map_size, PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
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size_t after_fixed_mmap = get_rss_kb();
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// store labels to all addresses.
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memset(p, val, map_size);
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size_t after_mmap_and_set_label2 = get_rss_kb();
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// munmap the addresses.
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munmap(p, map_size);
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size_t after_munmap = get_rss_kb();
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fprintf(
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stderr,
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"RSS at start: %zu, after mmap: %zu, after mmap+set label: %zu, after "
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"fixed map: %zu, after another mmap+set label: %zu, after munmap: %zu\n",
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before, after_mmap, after_mmap_and_set_label, after_fixed_mmap,
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after_mmap_and_set_label2, after_munmap);
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const size_t mmap_cost_kb = map_size >> 10;
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const size_t mmap_shadow_cost_kb = 2 * mmap_cost_kb;
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assert(after_mmap >= before + mmap_cost_kb);
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assert(after_mmap_and_set_label >= after_mmap + mmap_shadow_cost_kb);
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assert(after_mmap_and_set_label2 >= before + mmap_cost_kb + mmap_shadow_cost_kb);
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// RSS may not change memory amount after munmap to the same level as the
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// start of the program. The assert checks the memory up to a delta.
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const size_t delta = 5000;
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assert(after_fixed_mmap <= before + delta);
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assert(after_munmap <= before + delta);
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return 0;
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}
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