From 76d6efef547a23ba6e4e1ed0f1f198b36ae9c7ff Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Sat, 3 Mar 2012 23:14:31 +0100 Subject: [PATCH] linux-user: map at TARGET_UNMAPPED_BASE with reserved_va When mmap()'ing memory somewhere where it's not allowed, we should not default to the "next free page" which could be right after brk()'ed memory, but rather at TARGET_UNMAPPED_BASE, which ensures that brk() can extend its space later on. Reported-by: Bernhard M. Wiedemann Signed-off-by: Alexander Graf --- v1 -> v2: - use consistent constant naming --- linux-user/mmap.c | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-) diff --git a/linux-user/mmap.c b/linux-user/mmap.c index e4db455..2245f40 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -244,7 +244,13 @@ static abi_ulong mmap_find_vma_reserved(abi_ulong start, abi_ulong size) } prot = page_get_flags(addr); if (prot) { - last_addr = addr + qemu_host_page_size; + if (addr < TASK_UNMAPPED_BASE) { + /* Someone randomly shot into potential brk space, + better remap higher up when already remapping */ + last_addr = TASK_UNMAPPED_BASE; + } else { + last_addr = addr + qemu_host_page_size; + } } } mmap_next_start = addr;