On Sat, 30 Jul 2016 11:51:09 +0800 zhongjiang <zhongjiang@xxxxxxxxxx> wrote:
> From: zhong jiang <zhongjiang@xxxxxxxxxx>
>
> when compile the kenrel code, I happens to the following warn.
> fs/reiserfs/ibalance.c:1156:2: warning: ___new_insert_key___ may be used
> uninitialized in this function.
> memcpy(new_insert_key_addr, &new_insert_key, KEY_SIZE);
>
> The patch fix it by check the new_insert_ptr. if new_insert_ptr is not
> NULL, we ensure that new_insert_key is assigned. therefore, memcpy will
> saftly exec the operatetion.
>
> --- a/fs/reiserfs/ibalance.c
> +++ b/fs/reiserfs/ibalance.c
> @@ -1153,8 +1153,10 @@ int balance_internal(struct tree_balance *tb,
> insert_ptr);
> }
>
> - memcpy(new_insert_key_addr, &new_insert_key, KEY_SIZE);
> - insert_ptr[0] = new_insert_ptr;
> + if (new_insert_ptr) {
> + memcpy(new_insert_key_addr, &new_insert_key, KEY_SIZE);
> + insert_ptr[0] = new_insert_ptr;
> + }
>
> return order;
Jeff has aleady fixed this with an equivalent patch. It's in -mm at
present.
From: Jeff Mahoney <jeffm@xxxxxxxx>
Subject: reiserfs: fix "new_insert_key may be used uninitialized ..."
new_insert_key only makes any sense when it's associated with a
new_insert_ptr, which is initialized to NULL and changed to a buffer_head
when we also initialize new_insert_key. We can key off of that to avoid
the uninitialized warning.
Link: http://lkml.kernel.org/r/5eca5ffb-2155-8df2-b4a2-f162f105efed@xxxxxxxx
Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/reiserfs/ibalance.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff -puN fs/reiserfs/ibalance.c~reiserfs-fix-new_insert_key-may-be-used-uninitialized fs/reiserfs/ibalance.c
--- a/fs/reiserfs/ibalance.c~reiserfs-fix-new_insert_key-may-be-used-uninitialized
+++ a/fs/reiserfs/ibalance.c
@@ -1153,8 +1153,9 @@ int balance_internal(struct tree_balance
insert_ptr);
}
- memcpy(new_insert_key_addr, &new_insert_key, KEY_SIZE);
insert_ptr[0] = new_insert_ptr;
+ if (new_insert_ptr)
+ memcpy(new_insert_key_addr, &new_insert_key, KEY_SIZE);
return order;
}
_
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