f1a47181f5
Now that page aliasing for x64 has landed, we don't need to worry about passing tagged pointers to libc, and thus D98875 removed it. Unfortunately, we still test on aarch64 devices that don't have the kernel tagged address ABI (https://reviews.llvm.org/D98875#2649269). All the memory that we pass to the kernel in these tests is from global variables. Instead of having architecture-specific untagging mechanisms for this memory, let's just not tag the globals. Reviewed By: eugenis, morehouse Differential Revision: https://reviews.llvm.org/D101121
71 lines
2.0 KiB
C
71 lines
2.0 KiB
C
// Test that tagging a large region to 0 reduces RSS.
|
|
// RUN: %clang_hwasan -mllvm -hwasan-globals=0 -mllvm -hwasan-instrument-stack=0 %s -o %t && %run %t 2>&1
|
|
|
|
#include <assert.h>
|
|
#include <fcntl.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <sys/mman.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/types.h>
|
|
#include <unistd.h>
|
|
|
|
#include <sanitizer/hwasan_interface.h>
|
|
|
|
const unsigned char kTag = 42;
|
|
const size_t kNumShadowPages = 256;
|
|
const size_t kNumPages = 16 * kNumShadowPages;
|
|
const size_t kPageSize = 4096;
|
|
const size_t kMapSize = kNumPages * kPageSize;
|
|
|
|
void sync_rss() {
|
|
char *page = (char *)mmap(0, kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
|
|
// Linux kernel updates RSS counters after a set number of page faults.
|
|
for (int i = 0; i < 1000; ++i) {
|
|
page[0] = 42;
|
|
madvise(page, kPageSize, MADV_DONTNEED);
|
|
}
|
|
munmap(page, kPageSize);
|
|
}
|
|
|
|
size_t current_rss() {
|
|
sync_rss();
|
|
int statm_fd = open("/proc/self/statm", O_RDONLY);
|
|
assert(statm_fd >= 0);
|
|
|
|
char buf[100];
|
|
assert(read(statm_fd, &buf, sizeof(buf)) > 0);
|
|
size_t size, rss;
|
|
assert(sscanf(buf, "%zu %zu", &size, &rss) == 2);
|
|
|
|
close(statm_fd);
|
|
return rss;
|
|
}
|
|
|
|
void test_rss_difference(void *p) {
|
|
__hwasan_tag_memory(p, kTag, kMapSize);
|
|
size_t rss_before = current_rss();
|
|
__hwasan_tag_memory(p, 0, kMapSize);
|
|
size_t rss_after = current_rss();
|
|
fprintf(stderr, "%zu -> %zu\n", rss_before, rss_after);
|
|
assert(rss_before > rss_after);
|
|
size_t diff = rss_before - rss_after;
|
|
fprintf(stderr, "diff %zu\n", diff);
|
|
// Check that the difference is at least close to kNumShadowPages.
|
|
assert(diff > kNumShadowPages / 4 * 3);
|
|
}
|
|
|
|
int main() {
|
|
fprintf(stderr, "starting rss %zu\n", current_rss());
|
|
fprintf(stderr, "shadow pages: %zu\n", kNumShadowPages);
|
|
|
|
void *p = mmap(0, kMapSize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
|
|
fprintf(stderr, "p = %p\n", p);
|
|
|
|
test_rss_difference(p);
|
|
test_rss_difference(p);
|
|
test_rss_difference(p);
|
|
|
|
return 0;
|
|
}
|