During reviewing the source code, I found a comment which mention that
after f_op->mmap(), vma's start address can be changed.
I didn't verify that it is really possible, because there are so many
f_op->mmap() implementation. But if there are some mmap() which change
vma's start address, it is possible error situation, because we already
prepare prev vma, rb_link and rb_parent and these are related to original
address.
So add WARN_ON_ONCE for finding that this situtation really happens.
Signed-off-by: Joonsoo Kim <js1...@gmail.com>
diff --git a/mm/mmap.c b/mm/mmap.c
index 2d94235..36567b7 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1333,7 +1333,11 @@ munmap_back:
*
* Answer: Yes, several device drivers can do it in their
* f_op->mmap method. -DaveM
+ * Bug: If addr is changed, prev, rb_link, rb_parent should
+ * be updated for vma_link()
*/
+ WARN_ON_ONCE(addr != vma->vm_start);
+
addr = vma->vm_start;
pgoff = vma->vm_pgoff;
vm_flags = vma->vm_flags;
--
1.7.9.5
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
