diff --git a/compiler-rt/lib/dfsan/dfsan_interceptors.cpp b/compiler-rt/lib/dfsan/dfsan_interceptors.cpp --- a/compiler-rt/lib/dfsan/dfsan_interceptors.cpp +++ b/compiler-rt/lib/dfsan/dfsan_interceptors.cpp @@ -20,7 +20,19 @@ using namespace __sanitizer; -static bool interceptors_initialized; +namespace { + +bool interceptors_initialized; + +void ReleaseShadowMemoryPagesToOS(void *addr, SIZE_T length) { + uptr beg_shadow_addr = (uptr)__dfsan::shadow_for(addr); + void *end_addr = + (void *)((uptr)addr + RoundUpTo(length, GetPageSizeCached())); + uptr end_shadow_addr = (uptr)__dfsan::shadow_for(end_addr); + ReleaseMemoryPagesToOS(beg_shadow_addr, end_shadow_addr); +} + +} // namespace INTERCEPTOR(void *, mmap, void *addr, SIZE_T length, int prot, int flags, int fd, OFF_T offset) { @@ -34,7 +46,7 @@ res = REAL(mmap)(addr, length, prot, flags, fd, offset); if (res != (void *)-1) - dfsan_set_label(0, res, RoundUpTo(length, GetPageSize())); + ReleaseShadowMemoryPagesToOS(res, length); return res; } @@ -42,18 +54,14 @@ int fd, OFF64_T offset) { void *res = REAL(mmap64)(addr, length, prot, flags, fd, offset); if (res != (void *)-1) - dfsan_set_label(0, res, RoundUpTo(length, GetPageSize())); + ReleaseShadowMemoryPagesToOS(res, length); return res; } INTERCEPTOR(int, munmap, void *addr, SIZE_T length) { int res = REAL(munmap)(addr, length); if (res != -1) { - uptr beg_shadow_addr = (uptr)__dfsan::shadow_for(addr); - void *end_addr = - (void *)((uptr)addr + RoundUpTo(length, GetPageSizeCached())); - uptr end_shadow_addr = (uptr)__dfsan::shadow_for(end_addr); - ReleaseMemoryPagesToOS(beg_shadow_addr, end_shadow_addr); + ReleaseShadowMemoryPagesToOS(addr, length); } return res; } diff --git a/compiler-rt/test/dfsan/munmap_release_shadow.c b/compiler-rt/test/dfsan/munmap_release_shadow.c deleted file mode 100644 --- a/compiler-rt/test/dfsan/munmap_release_shadow.c +++ /dev/null @@ -1,54 +0,0 @@ -// RUN: %clang_dfsan %s -o %t && %run %t - -#include -#include -#include -#include -#include -#include -#include - -size_t get_rss_kb() { - long rss = 0L; - FILE *f = NULL; - assert((f = fopen("/proc/self/statm", "r"))); - assert(fscanf(f, "%*s%ld", &rss) == 1); - fclose(f); - return ((size_t)rss * (size_t)sysconf(_SC_PAGESIZE)) >> 10; -} - -int main(int argc, char **argv) { - const size_t map_size = 100 << 20; - size_t before = get_rss_kb(); - - char *p = mmap(NULL, map_size, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - const dfsan_label label = dfsan_create_label("l", 0); - char val = 0xff; - dfsan_set_label(label, &val, sizeof(val)); - memset(p, val, map_size); - size_t after_mmap = get_rss_kb(); - - munmap(p, map_size); - size_t after_munmap = get_rss_kb(); - - p = mmap(NULL, map_size, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - dfsan_set_label(label, &val, sizeof(val)); - memset(p, val, map_size); - size_t after_mmap2 = get_rss_kb(); - - fprintf(stderr, "RSS at start: %td, after mmap: %td, after mumap: %td, after mmap2: %td\n", - before, after_mmap, after_munmap, after_mmap2); - - // The memory after mmap increases 3 times of map_size because the overhead of - // shadow memory is 2x. - const size_t mmap_cost_kb = 3 * (map_size >> 10); - assert(after_mmap >= before + mmap_cost_kb); - // OS does not release memory to the same level as the start of the program. - // The assert checks the memory after munmap up to a delta. - const size_t delta = 50000; - assert(after_mmap2 <= after_mmap + delta); - - return 0; -} diff --git a/compiler-rt/test/dfsan/release_shadow_space.c b/compiler-rt/test/dfsan/release_shadow_space.c new file mode 100644 --- /dev/null +++ b/compiler-rt/test/dfsan/release_shadow_space.c @@ -0,0 +1,83 @@ +// RUN: %clang_dfsan %s -o %t && %run %t + +#include +#include +#include +#include +#include +#include +#include + +size_t get_rss_kb() { + size_t ret = 0; + pid_t pid = getpid(); + + char fname[256]; + sprintf(fname, "/proc/%ld/task/%ld/smaps", (long)pid, (long)pid); + FILE *f = fopen(fname, "r"); + assert(f); + + char buf[256]; + while (fgets(buf, sizeof(buf), f) != NULL) { + int64_t rss; + if (sscanf(buf, "Rss: %ld kB", &rss) == 1) + ret += rss; + } + assert(feof(f)); + fclose(f); + + return ret; +} + +int main(int argc, char **argv) { + const size_t map_size = 100 << 20; + size_t before = get_rss_kb(); + + // mmap and touch all addresses. The overhead is 1x. + char *p = mmap(NULL, map_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + memset(p, 0xff, map_size); + size_t after_mmap = get_rss_kb(); + + // store labels to all addresses. The overhead is 2x. + const dfsan_label label = dfsan_create_label("l", 0); + char val = 0xff; + dfsan_set_label(label, &val, sizeof(val)); + memset(p, val, map_size); + size_t after_mmap_and_set_label = get_rss_kb(); + + // fixed-mmap the same address. OS recyles pages and reinitializes data at the + // address. This should be the same to calling munmap. + p = mmap(p, map_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0); + size_t after_fixed_mmap = get_rss_kb(); + + // store labels to all addresses. + memset(p, val, map_size); + size_t after_mmap_and_set_label2 = get_rss_kb(); + + // munmap the addresses. + munmap(p, map_size); + size_t after_munmap = get_rss_kb(); + + fprintf( + stderr, + "RSS at start: %zu, after mmap: %zu, after mmap+set label: %zu, after " + "fixed map: %zu, after another mmap+set label: %zu, after munmap: %zu\n", + before, after_mmap, after_mmap_and_set_label, after_fixed_mmap, + after_mmap_and_set_label2, after_munmap); + + const size_t mmap_cost_kb = map_size >> 10; + const size_t mmap_shadow_cost_kb = 2 * mmap_cost_kb; + assert(after_mmap >= before + mmap_cost_kb); + assert(after_mmap_and_set_label >= after_mmap + mmap_shadow_cost_kb); + assert(after_mmap_and_set_label2 >= before + mmap_cost_kb + mmap_shadow_cost_kb); + + // RSS may not change memory amount after munmap to the same level as the + // start of the program. The assert checks the memory up to a delta. + const size_t delta = 5000; + assert(after_fixed_mmap <= before + delta); + assert(after_munmap <= before + delta); + + return 0; +}