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.