From 1afd6f137b3e3265c24fed6e8097ffaffc24c477 Mon Sep 17 00:00:00 2001 From: Jameson Nash Date: Wed, 21 Aug 2024 11:29:04 -0400 Subject: [PATCH] Revert "Don't expose guard pages to malloc_stack API consumers (#54591)" This reverts commit 5dfd57d25c189f6d5558dac9499b45f8bb9b271d. --- src/gc-stacks.c | 30 +----------------------------- 1 file changed, 1 insertion(+), 29 deletions(-) diff --git a/src/gc-stacks.c b/src/gc-stacks.c index 65173d3a8df37..28b24a1a29225 100644 --- a/src/gc-stacks.c +++ b/src/gc-stacks.c @@ -23,22 +23,13 @@ // number of stacks to always keep available per pool #define MIN_STACK_MAPPINGS_PER_POOL 5 -#if defined(_OS_WINDOWS_) || (!defined(_OS_OPENBSD_) && !defined(JL_HAVE_UCONTEXT) && !defined(JL_HAVE_SIGALTSTACK)) -#define JL_USE_GUARD_PAGE 1 const size_t jl_guard_size = (4096 * 8); -#else -const size_t jl_guard_size = 0; -#endif - static _Atomic(uint32_t) num_stack_mappings = 0; #ifdef _OS_WINDOWS_ #define MAP_FAILED NULL static void *malloc_stack(size_t bufsz) JL_NOTSAFEPOINT { - size_t guard_size = LLT_ALIGN(jl_guard_size, jl_page_size); - bufsz += guard_size; - void *stk = VirtualAlloc(NULL, bufsz, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE); if (stk == NULL) return MAP_FAILED; @@ -49,7 +40,6 @@ static void *malloc_stack(size_t bufsz) JL_NOTSAFEPOINT VirtualFree(stk, 0, MEM_RELEASE); return MAP_FAILED; } - stk = (char *)stk + guard_size; jl_atomic_fetch_add_relaxed(&num_stack_mappings, 1); return stk; @@ -58,12 +48,6 @@ static void *malloc_stack(size_t bufsz) JL_NOTSAFEPOINT static void free_stack(void *stkbuf, size_t bufsz) JL_NOTSAFEPOINT { -#ifdef JL_USE_GUARD_PAGE - size_t guard_size = LLT_ALIGN(jl_guard_size, jl_page_size); - bufsz += guard_size; - stkbuf = (char *)stkbuf - guard_size; -#endif - VirtualFree(stkbuf, 0, MEM_RELEASE); jl_atomic_fetch_add_relaxed(&num_stack_mappings, -1); } @@ -89,22 +73,16 @@ static void *malloc_stack(size_t bufsz) JL_NOTSAFEPOINT # else static void *malloc_stack(size_t bufsz) JL_NOTSAFEPOINT { -#ifdef JL_USE_GUARD_PAGE - size_t guard_size = LLT_ALIGN(jl_guard_size, jl_page_size); - bufsz += guard_size; -#endif - void* stk = mmap(0, bufsz, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (stk == MAP_FAILED) return MAP_FAILED; -#ifdef JL_USE_GUARD_PAGE +#if !defined(JL_HAVE_UCONTEXT) && !defined(JL_HAVE_SIGALTSTACK) // set up a guard page to detect stack overflow if (mprotect(stk, jl_guard_size, PROT_NONE) == -1) { munmap(stk, bufsz); return MAP_FAILED; } - stk = (char *)stk + guard_size; #endif jl_atomic_fetch_add_relaxed(&num_stack_mappings, 1); @@ -114,12 +92,6 @@ static void *malloc_stack(size_t bufsz) JL_NOTSAFEPOINT static void free_stack(void *stkbuf, size_t bufsz) JL_NOTSAFEPOINT { -#ifdef JL_USE_GUARD_PAGE - size_t guard_size = LLT_ALIGN(jl_guard_size, jl_page_size); - bufsz += guard_size; - stkbuf = (char *)stkbuf - guard_size; -#endif - munmap(stkbuf, bufsz); jl_atomic_fetch_add_relaxed(&num_stack_mappings, -1); }