Re: [PATCH 6.12.y 11/15] io_uring/msg_ring: ensure io_kiocb freeing is deferred for RCU

[Jens Axboe <axboe@kernel.dk>]

On 9/6/25 12:36 PM, Greg KH wrote:
> On Fri, Sep 05, 2025 at 07:23:00PM -0600, Jens Axboe wrote:
>> On 9/5/25 1:58 PM, Jens Axboe wrote:
>>> On 9/5/25 5:04 AM, Harshit Mogalapalli wrote:
>>>> diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
>>>> index 5ce332fc6ff5..3b27d9bcf298 100644
>>>> --- a/include/linux/io_uring_types.h
>>>> +++ b/include/linux/io_uring_types.h
>>>> @@ -648,6 +648,8 @@ struct io_kiocb {
>>>>  	struct io_task_work		io_task_work;
>>>>  	/* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */
>>>>  	struct hlist_node		hash_node;
>>>> +	/* for private io_kiocb freeing */
>>>> +	struct rcu_head		rcu_head;
>>>>  	/* internal polling, see IORING_FEAT_FAST_POLL */
>>>>  	struct async_poll		*apoll;
>>>>  	/* opcode allocated if it needs to store data for async defer */
>>>
>>> This should go into a union with hash_node, rather than bloat the
>>> struct. That's how it was done upstream, not sure why this one is
>>> different?
>>
>> Here's a test variant with that sorted. Greg, I never got a FAILED email
>> on this one, as far as I can tell. When a patch is marked with CC:
>> stable@vger.kernel.org and the origin of the bug clearly marked with
>> Fixes, I'm expecting to have a 100% reliable notification if it fails to
>> apply. If not, I just kind of assume patches flow into stable.
>>
>> Was this missed on my side, or was it on the stable side? If the latter,
>> how did that happen? I always ensure that stable has what it needs and
>> play nice on my side, but if misses like this can happen with the
>> tooling, that makes me a bit nervous.
>>
> 
> This looks like a failure on my side, sorry.  I don't see any FAILED
> email that went out for this anywhere, so I messed up.
> 
> sorry about that, and Harshit, thanks for noticing it.

Thanks for confirming, because I was worried it was on my side. But I
thought these things were fully automated? I'm going to add something on
my side to catch these in the future, just in case.

-- 
Jens Axboe