mm/fremap.c: fix oops on error path
If find_vma() fails, sys_remap_file_pages() will dereference `vma', which
contains NULL. Fix it by checking the pointer.
(We could alternatively check for err==0, but this seems more direct)
(The vm_flags change is to squish a bogus used-uninitialised warning
without adding extra code).
Reported-by: Tommi Rantala <tt.rantala@gmail.com>
Cc: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/fremap.c b/mm/fremap.c
index 0cd4c1148..6a8da7e 100644
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -163,7 +163,8 @@
* and that the remapped range is valid and fully within
* the single existing vma.
*/
- if (!vma || !(vma->vm_flags & VM_SHARED))
+ vm_flags = vma->vm_flags;
+ if (!vma || !(vm_flags & VM_SHARED))
goto out;
if (!vma->vm_ops || !vma->vm_ops->remap_pages)
@@ -254,7 +255,8 @@
*/
out:
- vm_flags = vma->vm_flags;
+ if (vma)
+ vm_flags = vma->vm_flags;
if (likely(!has_write_lock))
up_read(&mm->mmap_sem);
else