[PATCH 5.4 111/149] nvme-tcp: cant set sk_user_data without write_lock

Greg Kroah-Hartman
2021-07-19T16:58:11Z

From: Maurizio Lombardi <mlombard@redhat.com>

[ 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@redhat.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvme/target/tcp.c | 1 -
1 file changed, 1 deletion(-)

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:
--
2.30.2