This is a note to let you know that I've just added the patch titled nvme-tcp: can't set sk_user_data without write_lock to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: nvme-tcp-can-t-set-sk_user_data-without-write_lock.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 2122006e2a6527d752ab675c36bf9f5cf9db6551 Author: Maurizio Lombardi <mlombard@xxxxxxxxxx> Date: Fri Jul 2 10:11:21 2021 +0200 nvme-tcp: can't set sk_user_data without write_lock [ Upstream commit 0755d3be2d9bb6ea38598ccd30d6bbaa1a5c3a50 ] The sk_user_data pointer is supposed to be modified only while holding the write_lock "sk_callback_lock", otherwise we could race with other threads and crash the kernel. we can't take the write_lock in nvmet_tcp_state_change() because it would cause a deadlock, but the release_work queue will set the pointer to NULL later so we can simply remove the assignment. Fixes: b5332a9f3f3d ("nvmet-tcp: fix incorrect locking in state_change sk callback") Signed-off-by: Maurizio Lombardi <mlombard@xxxxxxxxxx> Reviewed-by: Sagi Grimberg <sagi@xxxxxxxxxxx> Signed-off-by: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c index 9bfd92b6677b..2ae846297d7c 100644 --- a/drivers/nvme/target/tcp.c +++ b/drivers/nvme/target/tcp.c @@ -1412,7 +1412,6 @@ static void nvmet_tcp_state_change(struct sock *sk) case TCP_CLOSE_WAIT: case TCP_CLOSE: /* FALLTHRU */ - sk->sk_user_data = NULL; nvmet_tcp_schedule_release_queue(queue); break; default: