From: Maximilian Riemensberger <riemensber...@cadami.net>
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 <riku.voi...@iki.fi>
CC: Laurent Vivier <laur...@vivier.eu>
CC: Peter Maydell <peter.mayd...@linaro.org>
Signed-off-by: Maximilian Riemensberger <riemensber...@cadami.net>
Reviewed-by: Laurent Vivier <laur...@vivier.eu>
Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
Message-Id: <1515286904-86418-1-git-send-email-riemensber...@cadami.net>
Signed-off-by: Laurent Vivier <laur...@vivier.eu>
---
linux-user/mmap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 4888f53139..0fbfd6dff2 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;
--
2.14.3
