From 95e6d4305affbbf5258c6a533be9bfd24599da90 Mon Sep 17 00:00:00 2001 From: Maximilian Riemensberger Date: Sun, 7 Jan 2018 01:01:44 +0000 Subject: linux-user/mmap.c: Avoid choosing NULL as start address mmap() is required by the linux kernel ABI and POSIX to return a non-NULL address when the implementation chooses a start address for the mapping. The current implementation of mmap_find_vma_reserved() can return NULL as start address of a mapping which leads to subsequent crashes inside the guests glibc, e.g. output of qemu-arm-static --strace executing a test binary stx_test: 1879 mmap2(NULL,8388608,PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANONYMOUS|0x20000,-1,0) = 0x00000000 1879 write(2,0xf6fd39d0,79) stx_test: allocatestack.c:514: allocate_stack: Assertion `mem != NULL' failed. This patch fixes mmap_find_vma_reserved() by skipping NULL as start address while searching for a suitable mapping start address. CC: Riku Voipio CC: Laurent Vivier CC: Peter Maydell Signed-off-by: Maximilian Riemensberger Reviewed-by: Laurent Vivier Reviewed-by: Richard Henderson Message-Id: <1515286904-86418-1-git-send-email-riemensberger@cadami.net> Signed-off-by: Laurent Vivier --- linux-user/mmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'linux-user/mmap.c') diff --git a/linux-user/mmap.c b/linux-user/mmap.c index 4888f53..0fbfd6d 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -234,7 +234,7 @@ static abi_ulong mmap_find_vma_reserved(abi_ulong start, abi_ulong size) if (prot) { end_addr = addr; } - if (addr + size == end_addr) { + if (addr && addr + size == end_addr) { break; } addr -= qemu_host_page_size; -- cgit v1.1