From 77ff614fa0319f7b4e99df29822d0590128bf00c Mon Sep 17 00:00:00 2001 From: Alexander Potapenko Date: Fri, 1 Aug 2025 12:12:42 +0200 Subject: executor: decouple kcov memory allocation from the trace On different platforms and in different coverage collection modes the pointer to the beginning of kcov buffer may or may not differ from the pointer to the region that mmap() returned. Decouple these two pointers, so that the memory is always allocated and deallocated with cov->mmap_alloc_ptr and cov->mmap_alloc_size, and the buffer is accessed via cov->data and cov->data_size. I tried my best to not break Darwin and BSD, but I did not test them. --- executor/executor_bsd.h | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) (limited to 'executor/executor_bsd.h') diff --git a/executor/executor_bsd.h b/executor/executor_bsd.h index b7cbdd4f5..88e1f46cb 100644 --- a/executor/executor_bsd.h +++ b/executor/executor_bsd.h @@ -71,7 +71,7 @@ static void cover_open(cover_t* cov, bool extra) #if GOOS_freebsd if (ioctl(cov->fd, KIOSETBUFSIZE, kCoverSize)) fail("ioctl init trace write failed"); - cov->mmap_alloc_size = kCoverSize * KCOV_ENTRY_SIZE; + cov->data_size = kCoverSize * KCOV_ENTRY_SIZE; #elif GOOS_openbsd unsigned long cover_size = kCoverSize; if (ioctl(cov->fd, KIOSETBUFSIZE, &cover_size)) @@ -83,7 +83,7 @@ static void cover_open(cover_t* cov, bool extra) if (ioctl(cov->fd, KIOREMOTEATTACH, &args)) fail("ioctl remote attach failed"); } - cov->mmap_alloc_size = kCoverSize * (is_kernel_64_bit ? 8 : 4); + cov->data_size = kCoverSize * (is_kernel_64_bit ? 8 : 4); #elif GOOS_netbsd uint64_t cover_size; if (extra) { @@ -100,18 +100,20 @@ static void cover_open(cover_t* cov, bool extra) if (ioctl(cov->fd, KCOV_IOC_SETBUFSIZE, &cover_size)) fail("ioctl init trace write failed"); } - cov->mmap_alloc_size = cover_size * KCOV_ENTRY_SIZE; + cov->data_size = cover_size * KCOV_ENTRY_SIZE; #endif } static void cover_mmap(cover_t* cov) { - if (cov->data != NULL) + if (cov->mmap_alloc_ptr != NULL) fail("cover_mmap invoked on an already mmapped cover_t object"); + cov->mmap_alloc_size = cov->data_size; void* mmap_ptr = mmap(NULL, cov->mmap_alloc_size, PROT_READ | PROT_WRITE, MAP_SHARED, cov->fd, 0); if (mmap_ptr == MAP_FAILED) fail("cover mmap failed"); + cov->mmap_alloc_ptr = (char*)mmap_ptr; cov->data = (char*)mmap_ptr; cov->data_end = cov->data + cov->mmap_alloc_size; cov->data_offset = is_kernel_64_bit ? sizeof(uint64_t) : sizeof(uint32_t); @@ -120,13 +122,13 @@ static void cover_mmap(cover_t* cov) static void cover_protect(cover_t* cov) { - if (cov->data == NULL) + if (cov->mmap_alloc_ptr == NULL) fail("cover_protect invoked on an unmapped cover_t object"); #if GOOS_freebsd size_t mmap_alloc_size = kCoverSize * KCOV_ENTRY_SIZE; long page_size = sysconf(_SC_PAGESIZE); if (page_size > 0) - mprotect(cov->data + page_size, mmap_alloc_size - page_size, + mprotect(cov->mmap_alloc_ptr + page_size, mmap_alloc_size - page_size, PROT_READ); #elif GOOS_openbsd int mib[2], page_size; @@ -135,20 +137,20 @@ static void cover_protect(cover_t* cov) mib[1] = HW_PAGESIZE; size_t len = sizeof(page_size); if (sysctl(mib, ARRAY_SIZE(mib), &page_size, &len, NULL, 0) != -1) - mprotect(cov->data + page_size, mmap_alloc_size - page_size, PROT_READ); + mprotect(cov->mmap_alloc_ptr + page_size, mmap_alloc_size - page_size, PROT_READ); #endif } static void cover_unprotect(cover_t* cov) { - if (cov->data == NULL) + if (cov->mmap_alloc_ptr == NULL) fail("cover_unprotect invoked on an unmapped cover_t object"); #if GOOS_freebsd size_t mmap_alloc_size = kCoverSize * KCOV_ENTRY_SIZE; - mprotect(cov->data, mmap_alloc_size, PROT_READ | PROT_WRITE); + mprotect(cov->mmap_alloc_ptr, mmap_alloc_size, PROT_READ | PROT_WRITE); #elif GOOS_openbsd size_t mmap_alloc_size = kCoverSize * sizeof(uintptr_t); - mprotect(cov->data, mmap_alloc_size, PROT_READ | PROT_WRITE); + mprotect(cov->mmap_alloc_ptr, mmap_alloc_size, PROT_READ | PROT_WRITE); #endif } -- cgit mrf-deployment