Re: [PATCH] bcache: fix uninitialized closure object

["Coly Li" <colyli@fnnas.com>]

> 2026年4月7日 21:24，Jens Axboe <axboe@kernel.dk> 写道：
> 
> On 4/7/26 7:19 AM, Coly Li wrote:
>>> 2026?4?7? 20:44?Jens Axboe <axboe@kernel.dk> ???
>>> 
>>> On 4/7/26 3:28 AM, Coly Li wrote:
>>>>> 2026?4?3? 19:11?Jens Axboe <axboe@kernel.dk> ???
>>>>> 
>>>>> On 4/2/26 10:21 PM, colyli@fnnas.com wrote:
>>>>>> From: Mingzhe Zou <mingzhe.zou@easystack.cn>
>>>>>> 
>>>>>> In the previous patch ("bcache: fix cached_dev.sb_bio use-after-free and
>>>>>> crash"), we adopted a simple modification suggestion from AI to fix the
>>>>>> use-after-free.
>>>>>> 
>>>>>> But in actual testing, we found an extreme case where the device is
>>>>>> stopped before calling bch_write_bdev_super().
>>>>>> 
>>>>>> At this point, struct closure sb_write has not been initialized yet.
>>>>>> For this patch, we ensure that sb_bio has been completed via
>>>>>> sb_write_mutex.
>>>>> 
>>>>> Presumably this should have a:
>>>>> 
>>>>> Fixes: fec114a98b87 ("bcache: fix cached_dev.sb_bio use-after-free and crash")
>>>>> 
>>>>> but for some reason it does not. I'll add it.
>>>> 
>>>> I did it on purpose. Because this patch is in Linux-stable and not in mainline,
>>>> I am not sure whether it is proper to reference the linux-block tree commit id.
>>>> 
>>>> This is why the patch title is mentioned in commit log, but commit id skipped.
>>> 
>>> Why is the patch in stable and not in mainline?! That should generally
>>> never happen.
>> 
>> Oops, My fingers movement diverged from my brain. I thought
>> linux-block, but typed linux-stable?.
>> 
>> I meant, when the patch merged from linux-block to Linus tree, maybe
>> the commit id changes for some unexpected reason. So I didn?t
>> reference the Fixes tag with linux-block tree commit id.
> 
> It'll never change going into Linus's tree, that's how git works. If I
> have a rare rebase for whatever reason, I fixup the Fixes shas. So
> always put them in there, there's never a reason NOT to do so.

This is a clear hint. Thanks.

Coly Li