Re: [PATCH] xfs: fix possible NULL dereference

Eric Sandeen
2013-10-21T23:12:24Z

On 10/21/13 5:44 PM, Dave Chinner wrote:
> On Mon, Oct 21, 2013 at 03:58:23PM -0500, Eric Sandeen wrote:
>> On 10/21/13 1:32 PM, Geyslan G. Bem wrote:
>>> This patch puts a 'break' in the true branch, avoiding the 'icptr->ic_next'
>>> dereferencing.
>>
>> Reviewed-by: Eric Sandeen <sandeen@redhat.com>
>
> Actually, NACK.

I felt that one coming ;)

>> Hm, yeah - cmn_err(CE_PANIC, " " ); used to BUG_ON, but the newer
>> xfs_emerg() doesn't.
>>
>> Dave, was that intentional?
>
> Of course it was. ;) xfs_emerg() is only called from the debug code
> in xlog_verify_iclog(), xlog_verify_tail_lsn and assfail().
>
> In the case of assfail(), it has it's own BUG() call, so it does
> everything just fine.
>
> In the case of xlog_verify_iclog() when icptr is NULL, it will
> panic immediately after the message is printed, just like the old
> code. i.e. this patch isn't fixing anything we need fixed.

A BUG() is probably warranted, then.

-Eric