[PATCH] uclinux: fix mmap() of directory for nommu case
I was playing with blackfin when i hit a neat bug ... doing an open() on a
directory and then passing that fd to mmap() would cause the kernel to hang
after poking into the code a bit more, i found that
mm/nommu.c:validate_mmap_request() checks the length and if it is 0, just
returns the address ... this is in stark contrast to mmu's
mm/mmap.c:do_mmap_pgoff() where it returns -EINVAL for 0 length requests ...
i then noticed that some other parts of the logic is out of date between the
two funcs, so perhaps that's the easy fix ?
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/nommu.c b/mm/nommu.c
index 8bdde95..6a2a8aa 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -497,15 +497,17 @@
(flags & MAP_TYPE) != MAP_SHARED)
return -EINVAL;
- if (PAGE_ALIGN(len) == 0)
- return addr;
-
- if (len > TASK_SIZE)
+ if (!len)
return -EINVAL;
+ /* Careful about overflows.. */
+ len = PAGE_ALIGN(len);
+ if (!len || len > TASK_SIZE)
+ return -ENOMEM;
+
/* offset overflow? */
if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
- return -EINVAL;
+ return -EOVERFLOW;
if (file) {
/* validate file mapping requests */