From: Lorne Li <lorneli.cs@xxxxxxxxx>
If previous check (pos and overflow check) fails, there's no
chance to use local variable inode, initialized by file_inode()
in the beginning of rw_verify_area().
So delay getting inode until actually needing it for check.
Signed-off-by: Lorne Li <lorneli.cs@xxxxxxxxx>
---
fs/read_write.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/read_write.c b/fs/read_write.c
index 153f8f6..ab63e87 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -368,7 +368,6 @@ int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t
loff_t pos;
int retval = -EINVAL;
- inode = file_inode(file);
if (unlikely((ssize_t) count < 0))
return retval;
pos = *ppos;
@@ -382,6 +381,7 @@ int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t
return retval;
}
+ inode = file_inode(file);
if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
retval = locks_mandatory_area(inode, file, pos, pos + count - 1,
read_write == READ ? F_RDLCK : F_WRLCK);
--
1.8.3.1
