Re: [PATCH AUTOSEL 6.6 054/139] net: tls: wait for async completion on last message

Sasha Levin
2024-10-06T00:31:17Z

On Wed, Oct 02, 2024 at 05:50:25AM -0700, Jakub Kicinski wrote:
>On Wed, 25 Sep 2024 08:07:54 -0400 Sasha Levin wrote:
>> From: Sascha Hauer <s.hauer@pengutronix.de>
>>
>> [ Upstream commit 54001d0f2fdbc7852136a00f3e6fc395a9547ae5 ]
>>
>> When asynchronous encryption is used KTLS sends out the final data at
>> proto->close time. This becomes problematic when the task calling
>> close() receives a signal. In this case it can happen that
>> tcp_sendmsg_locked() called at close time returns -ERESTARTSYS and the
>> final data is not sent.
>>
>> The described situation happens when KTLS is used in conjunction with
>> io_uring, as io_uring uses task_work_add() to add work to the current
>> userspace task. A discussion of the problem along with a reproducer can
>> be found in [1] and [2]
>>
>> Fix this by waiting for the asynchronous encryption to be completed on
>> the final message. With this there is no data left to be sent at close
>> time.
>
>I wouldn't backport this, it may cause perf regressions.

Dropped, thanks!

--
Thanks,
Sasha