From: Vincent Fazio <vfa...@gmail.com>
Previously, pgd_find_hole_fallback assumed that if the build host's libc
had MAP_FIXED_NOREPLACE defined that the address returned by mmap would
match the requested address. This is not a safe assumption for Linux
kernels prior to 4.17
Now, we always compare mmap's resultant address with the requested
address and no longer short-circuit based on MAP_FIXED_NOREPLACE.
Fixes: 2667e069e7b5 ("linux-user: don't use MAP_FIXED in
pgd_find_hole_fallback")
Signed-off-by: Vincent Fazio <vfa...@gmail.com>
Reviewed-by: Laurent Vivier <laur...@vivier.eu>
Reviewed-by: Alex Bennée <alex.ben...@linaro.org>
Message-Id: <20210131061930.14554-1-vfa...@xes-inc.com>
Signed-off-by: Laurent Vivier <laur...@vivier.eu>
---
linux-user/elfload.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 174ee7bad677..e525901659d4 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -2210,8 +2210,7 @@ static uintptr_t pgd_find_hole_fallback(uintptr_t
guest_size, uintptr_t brk,
PROT_NONE, flags, -1, 0);
if (mmap_start != MAP_FAILED) {
munmap(mmap_start, guest_size);
- if (MAP_FIXED_NOREPLACE != 0 ||
- mmap_start == (void *) align_start) {
+ if (mmap_start == (void *) align_start) {
return (uintptr_t) mmap_start + offset;
}
}
--
2.29.2
