From 8452130aa48a4ecfce975c1fcf002c3b20fb6480 Mon Sep 17 00:00:00 2001 From: Gabriel Corona Date: Thu, 22 May 2014 14:09:16 +0200 Subject: [PATCH] Revert "[mmalloc] Use mremap to expand heaps (heap collision prevention)" This is really how is should be handled. However, this does not work if someone has split the VMA in parts: this is done when creating stacks on the heap without MC, mprotect() is used to create a guard page for the stack. This reverts commit ba3185d8a4f0a56804d3b1ff24e596096f06a37c. --- src/xbt/mmalloc/mmorecore.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/src/xbt/mmalloc/mmorecore.c b/src/xbt/mmalloc/mmorecore.c index f47c53995d..9fbf7a9704 100644 --- a/src/xbt/mmalloc/mmorecore.c +++ b/src/xbt/mmalloc/mmorecore.c @@ -109,14 +109,9 @@ void *mmorecore(struct mdesc *mdp, ssize_t size) /* Let's call mmap. Note that it is possible that mdp->top is 0. In this case mmap will choose the address for us */ - if(mdp->base==mdp->top) - mapto = mmap(mdp->top, mapbytes, PROT_READ | PROT_WRITE, + mapto = mmap(mdp->top, mapbytes, PROT_READ | PROT_WRITE, MAP_PRIVATE_OR_SHARED(mdp) | MAP_IS_ANONYMOUS(mdp) | MAP_FIXED, MAP_ANON_OR_FD(mdp), foffset); - else { - size_t old_size = (char*)mdp->top - (char*)mdp->base; - mapto = mremap(mdp->base, old_size, old_size+size, 0); - } if (mapto == (void *) -1/* That's MAP_FAILED */) { char buff[1024]; @@ -129,6 +124,9 @@ void *mmorecore(struct mdesc *mdp, ssize_t size) abort(); } + if (mdp->top == 0) + mdp->base = mdp->breakval = mapto; + mdp->top = PAGE_ALIGN((char *) mdp->breakval + size); result = (void *) mdp->breakval; mdp->breakval = (char *) mdp->breakval + size; -- 2.20.1