[PATCH 1/3] procfs: fix unintended truncation of returned mapped address

[d.hatayama@xxxxxxxxxxxxxx (HATAYAMA Daisuke)]

Currently, proc_reg_get_unmapped_area truncates upper 32-bit of the
mapped virtual address returned from get_unmapped_area method in
pde->proc_fops due to the variable rv of signed integer on
x86_64. This is too small to have vitual address of unsigned long on
x86_64 since on x86_64, signed integer is of 4 bytes while unsigned
long is of 8 bytes. To fix this issue, use unsigned long instead.

Signed-off-by: HATAYAMA Daisuke <d.hatayama at jp.fujitsu.com>
---
 fs/proc/inode.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 9f8ef9b..6c501c4 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -288,7 +288,7 @@ static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
 static unsigned long proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr, unsigned long len, unsigned long pgoff, unsigned long flags)
 {
 	struct proc_dir_entry *pde = PDE(file_inode(file));
-	int rv = -EIO;
+	unsigned long rv = -EIO;
 	unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
 	if (use_pde(pde)) {
 		get_unmapped_area = pde->proc_fops->get_unmapped_area;