From a82be01198c1f3714f29f0a0e3ce3ed6d6bce0a6 Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Fri, 16 Sep 2016 19:39:24 +0200 Subject: erts: Fill freed EXEC memory with illegal instructions on DEBUG to get a nice SIGILL crash. For x86 and x86_64 only. --- erts/emulator/beam/erl_alloc.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'erts/emulator/beam') diff --git a/erts/emulator/beam/erl_alloc.c b/erts/emulator/beam/erl_alloc.c index 3c2c9def3b..d96b90fd55 100644 --- a/erts/emulator/beam/erl_alloc.c +++ b/erts/emulator/beam/erl_alloc.c @@ -4129,12 +4129,20 @@ debug_free(ErtsAlcType_t n, void *extra, void *ptr) ErtsAllocatorFunctions_t *real_af = (ErtsAllocatorFunctions_t *) extra; void *dptr; Uint size; + int free_pattern = n; ASSERT(ERTS_ALC_N_MIN <= n && n <= ERTS_ALC_N_MAX); dptr = check_memory_fence(ptr, &size, n, ERTS_ALC_O_FREE); - sys_memset((void *) dptr, n, size + FENCE_SZ); +#ifdef ERTS_ALC_A_EXEC +# if defined(__i386__) || defined(__x86_64__) + if (ERTS_ALC_T2A(ERTS_ALC_N2T(n)) == ERTS_ALC_A_EXEC) { + free_pattern = 0x0f; /* Illegal instruction */ + } +# endif +#endif + sys_memset((void *) dptr, free_pattern, size + FENCE_SZ); (*real_af->free)(n, real_af->extra, dptr); -- cgit v1.2.3