[Ocfs2-devel] [PATCH] ocfs2: dlm: fix lock migration crash

[Junxiao Bi]

Hi Andrew,

On 02/27/2014 08:48 AM, Andrew Morton wrote:
> On Wed, 26 Feb 2014 15:47:37 +0800 Junxiao Bi <junxiao.bi at oracle.com> wrote:
>
>> This issue was introduced by commit 800deef3 where it replaced list_for_each
>> with list_for_each_entry. The variable "lock" will point to invalid data if
>> "tmpq" list is empty and a panic will be triggered due to this.
>> Sunil advised reverting it back, but the old version was also not right. At
>> the end of the outer for loop, that list_for_each_entry will also set "lock"
>> to an invalid data, then in the next loop, if the "tmpq" list is empty, "lock"
>> will be an stale invalid data and cause the panic. So reverting the list_for_each
>> back and reset "lock" to NULL to fix this issue.
>>
>> ...
>>
>> Cc: <stable at vger.kernel.org>
> 800deef3 was back in 2007, so this doesn't seem a terribly urgent bugfix!
>
> I think what I'll do is to target 3.15-rc1 to give people time to
> review and test this.  But I'll retain the cc:stable so the fix gets
> backported into 3.14.x and earlier kernels.
>
> OK?
OK.  Thanks for merging it.

Thanks,
Junxiao.