It looks safe to release mmap_sem in the middle for vm_munmap and brk,
so passing "false" to do_munmap() call.
However it sounds not safe to mmap_region() which is called by
SyS_mmap().
Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index ad6ae7a..374e4ec 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -225,7 +225,7 @@ static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
/* Always allow shrinking brk. */
if (brk <= mm->brk) {
- if (!do_munmap(mm, newbrk, oldbrk-newbrk, &uf))
+ if (!do_munmap(mm, newbrk, oldbrk-newbrk, &uf, false))
goto set_brk;
goto out;
}
@@ -1643,7 +1643,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
/* Clear old maps */
while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
&rb_parent)) {
- if (do_munmap(mm, addr, len, uf))
+ if (do_munmap(mm, addr, len, uf, true))
return -ENOMEM;
}
@@ -2778,7 +2778,7 @@ int vm_munmap(unsigned long start, size_t len)
if (down_write_killable(&mm->mmap_sem))
return -EINTR;
- ret = do_munmap(mm, start, len, &uf);
+ ret = do_munmap(mm, start, len, &uf, false);
up_write(&mm->mmap_sem);
userfaultfd_unmap_complete(mm, &uf);
return ret;
@@ -2945,7 +2945,7 @@ static int do_brk_flags(unsigned long addr, unsigned long request, unsigned long
*/
while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
&rb_parent)) {
- if (do_munmap(mm, addr, len, uf))
+ if (do_munmap(mm, addr, len, uf, false))
return -ENOMEM;
}
--
1.8.3.1
