[PATCH 5.9 632/757] nvmet: fix uninitialized work for zero kato

Greg Kroah-Hartman
2020-10-27T16:37:55Z

From: zhenwei pi <pizhenwei@bytedance.com>

[ Upstream commit 85bd23f3dc09a2ae9e56885420e52c54bf983713 ]

When connecting a controller with a zero kato value using the following
command line

nvme connect -t tcp -n NQN -a ADDR -s PORT --keep-alive-tmo=0

the warning below can be reproduced:

WARNING: CPU: 1 PID: 241 at kernel/workqueue.c:1627 __queue_delayed_work+0x6d/0x90
with trace:
mod_delayed_work_on+0x59/0x90
nvmet_update_cc+0xee/0x100 [nvmet]
nvmet_execute_prop_set+0x72/0x80 [nvmet]
nvmet_tcp_try_recv_pdu+0x2f7/0x770 [nvmet_tcp]
nvmet_tcp_io_work+0x63f/0xb2d [nvmet_tcp]
...

This is caused by queuing up an uninitialized work. Althrough the
keep-alive timer is disabled during allocating the controller (fixed in
0d3b6a8d213a), ka_work still has a chance to run (called by
nvmet_start_ctrl).

Fixes: 0d3b6a8d213a ("nvmet: Disable keep-alive timer when kato is cleared to 0h")
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvme/target/core.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index b7b63330b5efd..90e0c84df2af9 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -1126,7 +1126,8 @@ static void nvmet_start_ctrl(struct nvmet_ctrl *ctrl)
* in case a host died before it enabled the controller. Hence, simply
* reset the keep alive timer when the controller is enabled.
*/
- mod_delayed_work(system_wq, &ctrl->ka_work, ctrl->kato * HZ);
+ if (ctrl->kato)
+ mod_delayed_work(system_wq, &ctrl->ka_work, ctrl->kato * HZ);
}

static void nvmet_clear_ctrl(struct nvmet_ctrl *ctrl)
--
2.25.1