From: Sagi Grimberg <sagi@grimberg.me>

Date: Wed, 10 Feb 2021 14:04:00 -0800

Subject: [PATCH] nvme-tcp: fix crash triggered with a dataless request

 submission

Git-commit: e11e5116171dedeaf63735931e72ad5de0f30ed5

Patch-mainline: v5.12-rc1

References: git-fixes

write-zeros has a bio, but does not have any data buffers associated

with it. Hence should not initialize the request iter for it (which

attempts to reference the bi_io_vec (and crash).

--

 run blktests nvme/012 at 2021-02-05 21:53:34

 BUG: kernel NULL pointer dereference, address: 0000000000000008

 #PF: supervisor read access in kernel mode

 #PF: error_code(0x0000) - not-present page

 PGD 0 P4D 0

 Oops: 0000 [#1] SMP NOPTI

 CPU: 15 PID: 12069 Comm: kworker/15:2H Tainted: G S        I       5.11.0-rc6+ #1

 Hardware name: Dell Inc. PowerEdge R640/06NR82, BIOS 2.10.0 11/12/2020

 Workqueue: kblockd blk_mq_run_work_fn

 RIP: 0010:nvme_tcp_init_iter+0x7d/0xd0 [nvme_tcp]

 RSP: 0018:ffffbd084447bd18 EFLAGS: 00010246

 RAX: 0000000000000000 RBX: ffffa0bba9f3ce80 RCX: 0000000000000000

 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000002000000

 RBP: ffffa0ba8ac6fec0 R08: 0000000002000000 R09: 0000000000000000

 R10: 0000000002800809 R11: 0000000000000000 R12: 0000000000000000

 R13: ffffa0bba9f3cf90 R14: 0000000000000000 R15: 0000000000000000

 FS:  0000000000000000(0000) GS:ffffa0c9ff9c0000(0000) knlGS:0000000000000000

 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033

 CR2: 0000000000000008 CR3: 00000001c9c6c005 CR4: 00000000007706e0

 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000

 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

 PKRU: 55555554

 Call Trace:

  nvme_tcp_queue_rq+0xef/0x330 [nvme_tcp]

  blk_mq_dispatch_rq_list+0x11c/0x7c0

  ? blk_mq_flush_busy_ctxs+0xf6/0x110

  __blk_mq_sched_dispatch_requests+0x12b/0x170

  blk_mq_sched_dispatch_requests+0x30/0x60

  __blk_mq_run_hw_queue+0x2b/0x60

  process_one_work+0x1cb/0x360

  ? process_one_work+0x360/0x360

  worker_thread+0x30/0x370

  ? process_one_work+0x360/0x360

  kthread+0x116/0x130

  ? kthread_park+0x80/0x80

  ret_from_fork+0x1f/0x30

--

Fixes: cb9b870fba3e ("nvme-tcp: fix wrong setting of request iov_iter")

Reported-by: Yi Zhang <yi.zhang@redhat.com>

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

Reviewed-by: Keith Busch <kbusch@kernel.org>

Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>

Tested-by: Yi Zhang <yi.zhang@redhat.com>

Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Hannes Reinecke <hare@suse.com>

---

 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 619b0d8f6e38..69f59d2c5799 100644

--- a/drivers/nvme/host/tcp.c

+++ b/drivers/nvme/host/tcp.c

@@ -2271,7 +2271,7 @@ static blk_status_t nvme_tcp_setup_cmd_pdu(struct nvme_ns *ns,

 	req->data_len = blk_rq_nr_phys_segments(rq) ?

 				blk_rq_payload_bytes(rq) : 0;

 	req->curr_bio = rq->bio;

-	if (req->curr_bio)

+	if (req->curr_bio && req->data_len)

 		nvme_tcp_init_iter(req, rq_data_dir(rq));

 	if (rq_data_dir(rq) == WRITE &&

-- 

2.29.2