[PATCH net] nvme-tcp: Fix comma-related oops

David Howells
2023-06-29T21:48:10Z

Fix a comma that should be a semicolon. The comma is at the end of an
if-body and thus makes the statement after (a bvec_set_page()) conditional
too, resulting in an oops because we didn't fill out the bio_vec[]:

BUG: kernel NULL pointer dereference, address: 0000000000000008
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
...
Workqueue: nvme_tcp_wq nvme_tcp_io_work [nvme_tcp]
RIP: 0010:skb_splice_from_iter+0xf1/0x370
...
Call Trace:
tcp_sendmsg_locked+0x3a6/0xdd0
tcp_sendmsg+0x31/0x50
inet_sendmsg+0x47/0x80
sock_sendmsg+0x99/0xb0
nvme_tcp_try_send_data+0x149/0x490 [nvme_tcp]
nvme_tcp_try_send+0x1b7/0x300 [nvme_tcp]
nvme_tcp_io_work+0x40/0xc0 [nvme_tcp]
process_one_work+0x21c/0x430
worker_thread+0x54/0x3e0
kthread+0xf8/0x130

Fixes: 7769887817c3 ("nvme-tcp: Use sendmsg(MSG_SPLICE_PAGES) rather then sendpage")
Reported-by: Aurelien Aptel <aaptel@nvidia.com>
Link: https://lore.kernel.org/r/253mt0il43o.fsf@mtr-vdi-124.i-did-not-set--mail-host-address--so-tickle-me/
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Sagi Grimberg <sagi@grimberg.me>
cc: Willem de Bruijn <willemb@google.com>
cc: Keith Busch <kbusch@kernel.org>
cc: Jens Axboe <axboe@fb.com>
cc: Christoph Hellwig <hch@lst.de>
cc: Chaitanya Kulkarni <kch@nvidia.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-nvme@lists.infradead.org
cc: netdev@vger.kernel.org
---
drivers/nvme/host/tcp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 3e7dd6f91832..9ce417cd32a7 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -1014,7 +1014,7 @@ static int nvme_tcp_try_send_data(struct nvme_tcp_request *req)
msg.msg_flags |= MSG_MORE;

if (!sendpage_ok(page))
- msg.msg_flags &= ~MSG_SPLICE_PAGES,
+ msg.msg_flags &= ~MSG_SPLICE_PAGES;

bvec_set_page(&bvec, page, len, offset);
iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, len);