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>
---
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 4888f53..20cc5a7 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -221,7 +221,7 @@ static abi_ulong mmap_find_vma_reserved(abi_ulong start,
abi_ulong size)
addr = end_addr - qemu_host_page_size;
while (1) {
- if (addr > end_addr) {
+ if (!addr || addr > end_addr) {
if (looped) {
return (abi_ulong)-1;
}
--
2.7.4
