[PATCH] fs: fix a bug when new_insert_key is not initialization

[PATCH] fs: fix a bug when new_insert_key is not initialization

[zhongjiang]

From: zhong jiang <zhongjiang@huawei.com>

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.

Signed-off-by: zhong jiang <zhongjiang@huawei.com>
---
 fs/reiserfs/ibalance.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/reiserfs/ibalance.c b/fs/reiserfs/ibalance.c
index b751eea..2c46829 100644
--- 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;
 }
-- 
1.8.3.1

Re: [PATCH] fs: fix a bug when new_insert_key is not initialization

[Andrew Morton]

On Sat, 30 Jul 2016 11:51:09 +0800 zhongjiang <zhongjiang@huawei.com> wrote:

> From: zhong jiang <zhongjiang@huawei.com>
> 
> 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@suse.com>
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@suse.com
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jan Kara <jack@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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;
 }
_

Re: [PATCH] fs: fix a bug when new_insert_key is not initialization

[zhong jiang]

On 2016/8/2 7:05, Andrew Morton wrote:
> On Sat, 30 Jul 2016 11:51:09 +0800 zhongjiang <zhongjiang@huawei.com> wrote:
>
>> From: zhong jiang <zhongjiang@huawei.com>
>>
>> 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@suse.com>
> 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@suse.com
> Signed-off-by: Jeff Mahoney <jeffm@suse.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
>  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;
>  }
> _
>
>
> .
>
 ok ,  I did not notice.  thanks.